Haier 1630167 FlexFit Series Dual Zone Mini Split System User Manual

Ductless Multi-Split Heat Pump

Service Manual

Design may vary by model number.

• Please read this manual before using the heat pump.

• Keep this user manual for future reference.

Table of Contents

Introduction ............................................................................................................... A- 1

Outdoor Technical Overview ...................................................................................... B-1

Wall Mount Technical Overview ..................................................................................C-1

Compact Cassette Technical Overview ......................................................................D-1

Large Cassette Technical Overview ............................................................................ E-1

Slim Duct Technical Overview .................................................................................... F-1

Mid-Static Ducted Technical Overview .......................................................................G-1

Medium Static Ducted (Pro Series) Technical Overview ..............................................H-1

Console Technical Overview ........................................................................................ I-1

Troubleshooting & Reference ..................................................................................... J-1

Outdoor

2U20EH2VHA

3U24EH2VHA

4U36EH2VHA

Indoor

Wall Mount - Highwall

AW07EH2VHA

AW09EH2VHA

AW12EH2VHA

AW18EH2VHA

AW07LC2VHB

AW09LC2VHB

AW12LC2VHB

AW18LC2VHB

AW24LP2VHA

2’x2’ Compact Cassette

AB09SC2VHA

AB12SC2VHA

AB18SC2VHA

3’x3’ Large Cassette

AL24LP2VHA

Slim Duct

AD07SL2VHB

AD09SL2VHB

AD12SL2VHB

AD18SL2VHB

Mid-Static Ducted

USYM09UCDSA

USYM12UCDSA

USYM18UCDSA

USYM24UCDSA

Medium Static Ducted

AM24LP2VHA

Console

USYF09UCDWA

USYF12UCDWA

USYF18UCDWA

• Before troubleshooting or servicing equipment, review equipment installation guides

and conrm ALL installation requirements & specications have been met. Including,

but not limited to: wiring, clearance, ducting (where applicable), power, and line set

requirements. Correct any installation issues before continuing.

Aug. 2020 - Manual release.

Revision History

INTRODUCTION

A-1

ENGLISH

INTRODUCTION

Table of Contents

Safety & Precautions............................................................................................................................................................. A-2

Specications ....................................................................................................................................................................... A-3

Outdoor Units ..................................................................................................................................................................... A-3

Highwall Indoor ................................................................................................................................................................... A-4

Ducted Indoor ..................................................................................................................................................................... A-4

Cassette Indoor .................................................................................................................................................................. A-5

Console Indoor .................................................................................................................................................................... A-5

Mid-Static Ducted Indoor ................................................................................................................................................... A-5

Functions and Control ........................................................................................................................................................... A-6

Auto Mode ............................................................................................................................................................................ A-6

Cooling Operation Mode ..................................................................................................................................................... A-6

Dry Mode (Dehumidifying Mode) ........................................................................................................................................ A- 6

Heat Mode ............................................................................................................................................................................ A-7

Indoor Fan Control ............................................................................................................................................................... A-7

Cold Air-Proof Operation .................................................................................................................................................... A-7

Timing .................................................................................................................................................................................. A-7

Indoor System Mode Conict ............................................................................................................................................. A-7

Abnormality Conrmation Approaches ............................................................................................................................. A-8

Low Load Protection Control .............................................................................................................................................. A- 8

High Load Protection Control ............................................................................................................................................. A-8

When the Compressor First Starts ..................................................................................................................................... A-8

The Outdoor Fan Control (Exchange Fan) .......................................................................................................................... A-8

The Outdoor Fan Control When In Cooling or Dehumidifying Mode ................................................................................ A- 8

The Control of the Outdoor Unit Expansion Valve ............................................................................................................ A-8

Four-Way Valve Control ...................................................................................................................................................... A-8

Antifreezing Protection ....................................................................................................................................................... A-8

Over-Temperature Heat Mode Indoor Coil......................................................................................................................... A-9

Topic Title

INTRODUCTION

A-2

ENGLISH

Safety & Precautions

• Read these Safety Precautions carefully to ensure correct installation.

• This manual classies the precautions by WARNING and CAUTION.

• Follow all precautions below. They are all important for ensuring safety and preventing property/equipment damage.

WARNING: Failure to follow any of WARNING is likely to result in grave consequences such as death or serious injury.

CAUTION: Failure to follow any of CAUTION may, in some cases, result in grave consequences.

• The following safety symbols are used throughout this manual:

Observe this instruction

Establish an earth connection

Never attempt

• After completing installation, test the unit to check for installation errors. Give the user adequate instructions concerning the

use and cleaning of the unit according to the Operation Manual.

WARNING

• Installation should be performed by the dealer or another professional.

Improper installation may cause water leakage, electrical shock, or re.

• Install the heat pump according to the instructions given in this manual.

Incomplete installation may cause water leakage, electrical shock, or re.

• Use only the supplied or specied installation parts.

Use of other parts may cause the unit to come lose, water leakage, electrical shock, or re.

• Install the heat pump on a solid base that can support the unit’s weight.

An inadequate base or incomplete installation may cause injury in the event the unit falls o the base.

• Electrical work should be carried out in accordance with the installation manual and national/local electrical wiring codes and

rules of practice.

Insucient capacity or incomplete electrical work may cause electrical shock or re.

• Use a dedicated power circuit. Never use a power supply shared by another appliance.

• For wiring, use a cable long enough to cover the entire distance with no splices.

Do not use an extension cord. Do not put other loads on the power supply, use a dedicated power circuit.

(Failure to do so may cause abnormal heat, electric shock or re.)

• Use only the specied wire types for electrical connections between the indoor and outdoor units.

Firmly clamp the interconnecting wires so they receive no external stresses. Incomplete connections or clamping may cause terminal over-

heating or re.

• After completing interconnecting and supply wiring connections, shape the cables so that they do not put undue force on the

electrical covers or panels.

Install covers over the wires. Incomplete cover installation may cause terminal overheating, electrical shock, or re.

• If any refrigerant has leaked out during the installation work, ventilate the room.

(The refrigerant produces a toxic gas if exposed to ame.)

• After all installation is complete, check for and repair any system refrigerant leaks.

(The refrigerant produces a toxic gas if exposed to ames.)

•When installing or relocating the system, keep the refrigerant circuit free from substances other than the specied

refrigerant (R410A), such as air.

(The presence of air or other foreign substance in the refrigerant circuit causes an abnormal pressure rise or rupture, resulting in injury.)

• During pump-down, stop the compressor before removing the refrigerant piping.

If the compressor is still running, and the stop valve is open during pump-down, air will be sucked into the system while the compressor is

running. This will cause abnormal pressure and noncondensables added to the system.

• Be sure to establish a ground. Do not ground the unit to a utility pipe, arrester, or telephone earth.

An complete earth may cause electrical shock, or re. A high surge current from lightning or other sources may

cause damage to the heat pump.

CAUTION

• Do not install the heat pump in a place where there is danger of exposure to ammable gas.

If the gas builds up around the unit, it may catch re.

• Install drain piping according to the instructions of this manual.

Inadequate piping may cause ooding.

•Tighten the are nut according to the specied torque using a torque wrench.

If the are nut is overtightened, the are nut may eventually crack and cause refrigerant leakage.

• Provide adequate measures to prevent the outdoor unit from being used as a shelter by rodents.

Rodents making contact with electrical parts can cause malfunctions, smoke or re. Please instruct the customer to keep the area around

the unit clean.

Topic Title

INTRODUCTION

A-3

ENGLISH

Specications

2U20EH2VHA 3U24EH2VHA 4U36EH2VHA

Cooling

Non-Ducted

Rated Capacity Btu/hr 18,100 22,000 34,000

Capacity Range Btu/hr 7000-20000 6000-23600 6000-38000

Rated Power Input W 1448 1760 2,740

SEER/ EER 17/12.5 18.5/12.5 20 /12.5

Cooling Ducted

Rated Capacity Btu/hr 18,100 21,000 34,400

Capacity Range Btu/hr 6000-19000 6000-22300 6000-37000

Rated Power Input W 1724 2000 2,740

SEER/EER 15/10.5 15/10.5 17.00 /10.00

Heating

Non-Ducted

Rated Heating Capacity 47°F Btu/hr 20,000 24,000 36,000

Heating Capacity Range Btu/hr 8000-23000 8000-30600 8000-39000

Rated Power Input W 1504 1572 2,710

HSPF 10.5 10.5 10.5

COP @ 5°F 2.0 2.0 2.0

Max. Heating Capacity 5°F Btu/hr 23000 24000 36,000

Max. Heating Capacity -15°F Btu/hr 17000 18000 25,000

Heating Ducted

Rated Heating Capacity 47°F Btu/hr 20,000 22,000 35,000

Heating Capacity Range Btu/hr 8000-21000 8000-28600 8000-39000

Rated Power Input W 2255 2230 2710

COP/ COP @ 5°F 2.94/1.9 3/1.9 2.64/1.9

HSPF 9.6 9.3 10.5

Max. Heating Capacity 5°F Btu/hr 19000 20000 35,000

Max. Heating Capacity -15°F Btu/hr 15000 16000 25,200

Power Supply

Voltage, Cycle, Phase V/Hz/- 208-230/60/1 208-230/60/1 208-230/60/1

Wire Size between ID and OD 14/4 AWG Stranded 14/4 AWG Stranded 14/4 AWG Stranded

Compressor Type DC Inverter Driven Rotary DC Inverter Driven Rotary DC Inverter Driven Rotary

Maximum Fuse Size A 25 25 40

Minimum Circuit Amp A 15 16 30

Outdoor Unit

Outdoor Fan Speed RPM 300~900 300~900 300~900

Outdoor Noise Level dB 56 56 55

Dimension: Height in (mm) 33.1(840) 33.1(840) 38.0 (965)

Dimension: Width in (mm) 37.3(948) 37.3(948) 37.4(950)

Dimension: Depth in (mm) 13.4(340) 13.4(340) 14.6(370)

Weight (Ship/Net)- lbs (kg) 202.3/185.6 (91.7/84.2) 205.9/189.5 (93.4/85.9) 241/221 (109.7/100.6)

Connectable Indoor unit quantity 2 2 or 3 2 3 or 4

Refrigerant Lines

Connections Flare Flare Flare

Liquid O.D. in 1/4 1/4 1/4 1/4 1/4 1/4 1/4 1/4

Suction O.D. in 3/8 3/8 3/8 3/8 1/2 3/8 3/8 3/8 1/2

Factory Charge Oz 99 99 113

Maximum Line Length Ft / m 164/50 196/60 230/70

Maximum Height Ft / m 50/15 50/15 50/15

Maximum Line Length for each individual

indoor unit Ft / m

82/25 82/25 82/25

2 Zones 3 Zones 4 Zones

Compressor Type:

DC Inverter Driven Rotary

Voltage/Cycle/Phase:

208-230/60/1

Operating Range (

F):

-22 1151450-4

-15

Cooling

Heating

Outdoor Units

Topic Title

INTRODUCTION

A-4

ENGLISH

Specications

AW07EH2VHA AW09EH2VHA AW12EH2VHA AW18EH2VHA

Rated Cooling Capacity Btu/hr 7,000 9,000 12,000 19,000

Rated Heating Capacity Btu/hr 10,000 12,000 16,500 20,400

Voltage, Cycle, Phase V/Hz/- 208-230/60/1 208-230/60/1 208-230/60/1 208-230/60/1

Airow CFM

(Turbo/H/M/L/Quiet)

420/360/300/240/180 470/410/350/290/230 440/410/380/311/260 710/650/560/440/410

Indoor Sound dB

(Turbo/H/M/L/Quiet)

42/39/37/28/23 42/39/37/28/23 42/39/37/28/23 49/47/42/36/34

Dimension: H x W x D in (mm)

12 1/4 x 35 3/8 x 8 1/4

(310 x 900 x 210)

12 1/4 x 35 3/8 x 8 1/4

(310 x 900 x 210)

12 1/4 x 35 3/8 x 8 1/4

(310 x 900 x 210)

14 3/8 x 43 7/8 x 9 5/8

(336 x 1115 x 243)

Weight (Ship/Net)- lbs (kg) 30.9/25.3 (14/11.5) 30.9/25.3 (14/11.5) 30.9/25.3 (14/11.5) 45.4/37.5 (20.6/17)

Liquid /Suction O.D. in 1/4 3/8 1/4 3/8 1/4 3/8 1/4 1/2

AD07SL2VH(-) AD09SL2VH(-) AD12SL2VH(-) AD18SL2VH(-) AM24LP2VH(-)

Rated Cooling Capacity Btu/hr 7,000 9,000 12,000 18,000 24000

Rated Heating Capacity Btu/hr 8,000 10,000 13,000 19,000 27000

Voltage, Cycle, Phase V/Hz/- 208-230/60/1 208-230/60/1 208-230/60/1 208-230/60/1 208-230/60/1

Airow CFM (Turbo/H/M/L/Quiet) 353/312/270/230/188 353/312/270/230/188 400/353/282/247/218 540/500/447/365/306 845/670/530/470

Max. Ext. Static Pressure

in.W.G (Pa)

0.16 (40) 0.16 (40) 0.16 (40) 0.16 (40) 0.6 (150)

Indoor Sound dB

(Turbo/H/M/L/Quiet)

35/33/29/26/21 35/33/29/26/22 38/35/29/26/23 31/29/23/29/25 38/35/32/29

Dimension: HxWxD in (mm)

7 5/16 x 33 7/16 x16 9/16

(185x850x420)

7 5/16 x 33 7/16 x16 9/16

(185x850x420)

7 5/16 x 33 7/16 x16 9/16

(185x850x420)

7 5/16 x 46 1/16 x16 9/16

(185x1170x420)

9 7/8 x 37 5/8 x 25 3/4

(250x957x655)

Weight (Ship/Net)- lbs (kg) 47.2/36.8 (21.4/16.7) 47.2/36.8 (21.4/16.7) 47.2/36.8 (21.4/16.7) 61.8/48.5 (28/22) 68.8/81.1 (31.2/36.8)

Liquid / Suction O.D. in 1/4 3/8 1/4 3/8 1/4 3/8 1/4 1/2 3/8 5/8

Drainpipe Size O.D. in 1 1/4 1 1/4 1 1/4 1 1/4 1 1/4

Condensate Pump Standard Standard Standard Standard Standard

Max. Drain-Lift height in(mm) 27 9/16 (700) 27 9/16 (700) 27 9/16 (700) 27 9/16 (700) 27 9/16 (700)

AW07LC2VH(-) AW09LC2VH(-) AW12LC2VH(-) AW18LC2VH(-) AW24LP2VH(-)

Rated Cooling Capacity Btu/hr 7,000 9,000 12,000 18,000 22,000

Rated Heating Capacity Btu/hr 8,000 10,000 13,000 19,000 24,000

Voltage, Cycle, Phase V/Hz/- 208-230/60/1 208-230/60/1 208-230/60/1 208-230/60/1 208-230/60/1

Airow CFM

(Turbo/H/M/L/Quiet)

410/350/295/235/205 410/350/295/235/205 440/380/320/265/215 636/530/483/430/383 710/650/560/440/410

Indoor Sound dB

(Turbo/H/M/L/Quiet)

43/38/33/26/22 43/38/33/26/22 44/39/34/27/23 48/45/40/35/30 49/47/42/36/34

Dimension: H x W x D in (mm)

11 x 33 5/8 x 8 1/16

(280 x 855 x 204)

11 x 33 5/8 x 8 1/16

(280 x 855 x 204)

11 x 33 5/8 x 8 1/16

(280 x 855 x 204)

12 3/4 x 39 1/4 x 9 1/4

(332 x 997 x 235)

13 1/4 x 43 7/8 x 9 9/16

(336 x 1115 x 243)

Weight (Ship/Net)- lbs (kg) 26.8/22 (12.2/10) 26.8/22 (12.2/10) 26.8/22 (12.2/10) 35.3/28.6 (16/13) 45.4/37.5 (20.6/17)

Liquid /Suction O.D. in 1/4 3/8 1/4 3/8 1/4 3/8 1/4 1/2 3/8 5/8

Highwall Indoor

Ducted Indoor

Topic Title

INTRODUCTION

A-5

ENGLISH

Specications

AB09SC2VH(-) AB12SC2VH(-) AB18SC2VH(-) AL24LP2VH(-)

Rated Cooling Capacity Btu/hr 9,000 12,000 18,000 24200

Rated Heating Capacity Btu/hr 10,000 13,000 19,000 27300

Voltage, Cycle, Phase V/Hz/- 208-230/60/1 208-230/60/1 208-230/60/1 208-230/60/1

Airow CFM

(Turbo/H/M/L/Quiet)

410/365/305/265/205 410/365/305/265/205 470/410/365/295/252 740/630/480/400

Indoor Sound dB

(Turbo/H/M/L/Quiet)

42/40/36/32/25 42/40/36/32/25 45/42/40/36/32 38/35/32/29

Grille Model PB-700KB PB-700KB PB-700KB PB-950KB

Chassis Dimension:

HxWxD in (mm)

10 1/4 x 22 7/16 x 2 3/8

(260 x 570 x 570)

10 1/4 x 22 7/16 x 2 3/8

(260 x 570 x 570)

10 1/4 x 22 7/16 x 2 3/8

(260 x 570 x 570)

9 5/8 x 33 1/8 x 33 1/8 (246 x 840

x840)

Grille Dimension: HxWxDin (mm)

2 3/8 x 27 9/16 x 27 9/16

(60 x 700 x 700)

2 3/8 x 27 9/16 x 27 9/16

(60 x 700 x 700)

2 3/8 x 27 9/16 x 27 9/16

(60 x 700 x 700)

2 x 3 1/8 x 3 1/8

(50 x 950 x 950)

Weight (Ship/Net)- lbs (kg) 46.3/37.5 (21/17) 46.3/37.5 (21/17) 46.3/37.5 (21/17) 68.4/79.4 (31/36)

Liquid / Suction O.D. in 1/4 3/8 1/4 3/8 1/4 1/2 3/8 5/8

Drainpipe Size O.D. in 1 1/4 1 1/4 1 1/4 1

Condensate Pump Standard Standard Standard Standard

Max. Drain-Lift height in(mm) 27 9/16 (700) 27 9/16 (700) 27 9/16 (700) 47 1/4(1200)

Cassette Indoor

USYF09UCDWA USYF12UCDWA USYF18UCDWA

Rated Cooling Capacity Btu/hr 9,000 12,000 15,000

Rated Heating Capacity Btu/hr 10,000 13,000 18,000

Voltage, Cycle, Phase V/Hz/- 208-230/60/1 208-230/60/1 208-230/60/1

Airow (Turbo/High/Med/Low/Quiet) CFM 264/235/205/176/147 294/264//205/176/147 341/311/282/252/223

Indoor Sound Level dB (Turbo/High/Med/Low/Quiet) 40/32/25/20 42/34/26/21 46/37/33/28

Chassis Dimension: HxWxD in (mm) 23.6/27.5/8.3 (600/700/210)

Weight (Ship/Net)- lbs (kg) 36/40 (16.5/18.5)

Liquid / Suction O.D. in 1/4 3/8 1/4 3/8 1/4 1/2

Drainpipe Size O.D. in 1 1/4 1 1/4 1 1/4

Built-in WiFi

Console Indoor

Mid-Static Ducted Indoor

USYM09UCDSA USYM12UCDSA USYM18UCDSA USYM24UCDSA

Rated Cooling Capacity Btu/hr 9,000 12,000 18,000 24000

Rated Heating Capacity Btu/hr 10,000 13,000 19,000 25000

Voltage, Cycle, Phase V/Hz/- 208-230/60/1 208-230/60/1 208-230/60/1 208-230/60/1

Airow (Turbo/High/Med/Low/Quiet) CFM 494/423/352/264 494/423/352/264 635/529/458/388 845/670/530/470

Max. External Static Pressure in.W.G (Pa) 0.6 (150) 0.6 (150) 0.6 (150) 0.6 (150)

Indoor Sound Level dB

(Turbo/High/Med/Low/Quiet)

35/32/29/26 35/32/29/26 37/34/32/29 39/36/33/30

Chassis Dimension: HxWxD in (mm) 27.5/27.5/9.7(700/700/248) 27.5/27.5/9.7(700/700/248) 43.3/27.5/9.7(1100/700/248) 43.3/27.5/9.7(1100/700/248)

Weight (Ship/Net)- lbs (kg) 57/66(26/30) 57/66(26/30) 70/77 (32/35) 70/77 (32/35)

Liquid / Suction O.D. in 1/4 3/8 1/4 3/8 1/4 1/2 3/8 5/8

Drainpipe Size O.D. in 1 1/4 1 1/4 1 1/4 1 1/4

Condensate Pump Standard Standard Standard Standard

Max. Drain-Lift height in(mm) 39(1000) 39(1000) 39(1000) 39(1000)

Built-in WiFi

INTRODUCTION

A-6

ENGLISH

Functions and Control

Auto Mode

When the running mode is turned to auto after starting the

system, the system will rst determine the running mode

according to the current room temperature and then will

run according to the determined mode: Tr means room

temperature; Ts means temperature setting; Tp means

temperature of indoor coil pipe

Tr≥73°F Choose Cooling Mode

Tr<73°F Choose Heating Mode

After turning to the auto mode, the running mode will be

switched between cooling mode, fan mode, and heating mode

according to the change of the indoor ambient temperature.

There is a 15 minute delay between mode changes.

Cooling Operation Mode

Temperature control range: 60°F---86°F

Temperature dierence: ±2°F

• Control features: When Tr (input airow)>Ts (set

temperature) °F, the indoor fan will operate at the set speed,

the mode signal will be sent to the outdoor system, and

the compressor will start. When Tr (input airow)< Ts (set

temperature)°F, the indoor fan will operate at the set speed,

and the mode signal will be sent to the outdoor system, and

the compressor will stop. The system will keep the original

status if Tr= Ts.

Airow speed control: (temperature dierence ±2°F)

Automatic:

When Tr≤Ts +4°F high speed.

When Ts+2°F≤Tr<Ts+5°F, medium speed

When Tr<Ts+2°F, low speed

When the sensor is o, low speed

When the airow speed has no delay from the high to low

switching, the speed should be delayed for 3 minutes (remain

at high speed for 3 minutes.) before the next switch.

When the system is operating, you can set the high, medium

or low speed manually. (When the sensor is on or o, the

system will change the speed 2 seconds after receiving the

signal.)

• Louver control: the location for the louver can be set

according to your needs.

• Defrosting function: preventing the frosting on the indoor

heat exchanger (when cooling or dehumidifying). When

the compressor works continuously for 1 to 6 minutes

(adaptable in EEPROM) and the temperature of the indoor

coils has been below 32°F for 10 seconds, the compressor

will be stopped and the malfunction will be recorded in the

malfunction list. The indoor system will continue to run.

When the temperature of the indoor coil is raised to 45°F,

the compressor will be restarted again (the requirement of 3

minutes’ delay should be satised.)

Dry Mode (Dehumidifying Mode)

• Temperature control range: 60-86°F

• Temperature dierence: ±2°F

Control feature: Send the dehumidifying signal to the outdoor

system.

When Tr>Ts+4°F, the compressor will be turned on, the indoor

fan will operate at the set speed. When Tr is between the

Ts and Ts+4°F, the outdoor system will operate at the high

dehumidifying frequency for 10 minutes and then at the low

dehumidifying mode for six minutes. The indoor fan will

operate at low speed.

When Tr< Ts, the outdoor system will be stopped, the indoor

fan will be stopped for 3 minutes and then turned to the low

speed option.

All the frequency conversions have a ±2°F dierence.

• Wind speed control: Automatic:

When Tr≥ Ts+ 9°F, high speed.

When Ts+5°F≤Tr< Ts+9°F, medium speed.

When Ts+4°F≤Tr< Ts+5°F, low speed.

When Tr<Ts+4°F, light speed.

If the outdoor fan is stopped, the indoor fan will be paused for

3 minutes.

If the outdoor fan is stopped for more than 3 minutes and the

outdoor system still operates, the system will be changed into

light speed mode.

When the airow speed has no delay from the high to low

switching, the speed should be delayed for 3 minutes (remain

at high speed for 3 minutes) before the next switch.

When the sensor is o or Tr< Ts+5°F, the manual operation can

not be made (obligatory automatic operation).

• Louver location control: the location for the louver can be

set according to your needs.

• Defrosting function: preventing the frosting on the

indoor heat exchanger (when cooling or dehumidifying).

When the compressor works continuously for 16 minutes

(adaptable in EEPROM) and the temperature of the indoor

coils has been below 32°F for 10 second, the compressor

will be stopped and the malfunction will be recorded in the

malfunction list. The indoor system will continue to run.

When the temperature of the indoor coil is raised to 45°F,

the compressor will be restarted again (the requirement of 3

minutes’ delay should be satised.)

INTRODUCTION

A-7

ENGLISH

Functions and Control

Heat Mode

• Temperature control range: 60-86°F

• Temperature dierence: ±2°F

Control feature: the temperature compensation is

automatically added and the system will send the heating

signals to the outdoor system.

If Tr≤Ts, the outdoor compressor is turned on, the indoor fan

will be at the cold air proof mode.

If Tr>Ts+, the outdoor system is turned o, the indoor fan will

be at the heat residue sending mode.

If Tr<Ts+, the outdoor system will be turned on again, the

indoor fan will be in the cold air proof mode.

Indoor Fan Control

Manual Control: You can choose high, medium, low and

automatic speed control. Automatic:

When Tr<Ts, high speed.

When Ts≤Tr≤Ts+4°F, medium speed.

When Tr> Ts+4°F, low speed.

When the airow speed has no delay from the high to low

switching, the speed should be delayed for 3 minutes (remain

at high speed for 3 minutes.) before the next switch.

• Louver location control: the location for the louver can be

set according to your needs.

Cold Air-Proof Operation

1. The indoor operation within 4 minutes after the start up is

as the following diagram, the air speed can be raised only

after the speed has reached a certain level.

• Residue heat sending. The indoor fan will send the residue

heat at a low speed for 12 seconds.

• If other conditions are satised, when the compressor stops,

the indoor system will operate at a light speed. The indoor

fan will stop when the coil temperature is below the heat

start temp 4’.

• Defrosting. When the system receives the defrosting signal

from outdoors, the indoor fan will stop and the indoor

temperature display won’t change. At this time, any indoor

coil malfunctions will be neglected. When the outdoor

defrosting nishes, the coil malfunction will still be neglected

until the compressor has been started up for 30 seconds.

The indoor temperature display will not change and the

system operates at the cold air proof mode.

• Automatic heating temperature compensation: when

the system enters the heating mode, the temperature

compensation (4) will be added. When the status is switched

o, the compensation will be erased.

Timing

You can set 24 hours on/o timing. After setting, the timing

indicator will be displayed. Also, the light will turn o after the

timing is set. The followings are several timing methods:

1. System ON timing: The timing indicator will be displayed

and the indoor system is under the waiting mode. The light

will be turned o when the timing is nished and the rest

of the system will operate under a normal condition. The

timing starts since the last reception of the timing signal.

2. System /OFF timing: When the system is turned on, the

timing indicator will be displayed; the rest of the system

will operate under normal conditions. When the set time

expires, the indicator display will turn o and the system

will turn o. If you have set the dormant functions, the

order of your settings will be operated according to the

timing settings.

3. System ON/OFF timing: The settings will be completed

according to the settings.

2. 4 minutes after the start up of the indoor fan, the light

airow and the low airow will be turned to the set speed

airow.

3. In the cold air proof operation, the fan won’t stop after the

start up.

4. During the cold air proof operation, the indoor system

will continuously send ‘indoor high speed’ signals to the

outdoor system.

Indoor System Mode Conict

The indoor unit is trying to operate in a mode that is opposite

of the mode the outdoor unit is currently operating in. Change

the operating mode to either heat or cool, or the indoor unit

will shut o.

INTRODUCTION

A-8

ENGLISH

Functions and Control

Abnormality Conrmation Approaches

1. Indoor temperature sensor abnormality:

Under the operation, the normal temperature ranges from

120°F to -30°F. When the temperature goes beyond this

range, the abnormality can be conrmed. If the temperature

goes back into the range, the system will automatically

resume.

2. Indoor heat interaction sensor abnormality:

Under the operation, the normal temperature ranges from

120°F to -30°F. When the temperature goes beyond this

range, the abnormality can be conrmed. If the temperature

goes back into the range, the system will automatically

resume.

3. Indoor/Out door malfunction:

When the indoor system receives the outdoor malfunction

codes, it will store the code into E2 for the malfunction list

resume. The indoor system will continue to operate according

to the original status, the malfunction code will not be

revealed or processed.

4. Transmission abnormality:

If the indoor system can’t receive the outdoor system for 8

minutes, the communication abnormality can be conrmed

and reported and the outdoor system will be stopped.

Low Load Protection Control

In order to prevent the frosting of the indoor heat interaction

device, the outdoor system will be stopped if the indoor heat

interaction temperature is 32°F for 5 minutes, but the fan will

continue to operate. The outdoor system will be started again

when the heat interaction temperature is above 108°F, and the

system has been stopped for 3 minutes. The malfunction will

be stored in the malfunction resume and will not be revealed.

High Load Protection Control

The outdoor system will be stopped if the coil temperature is

above 149°F for 2 minutes. The indoor fan will be controlled by

the thermostat. The outdoor system can be restarted when

the coil temperature is below 108°F and the system has been

stopped for 3 minutes. The malfunction will be stored in the

malfunction resume and will not be revealed.

When the Compressor First Starts

The compressor will start in low frequency. After a brief time

delay, the compressor will come up to operating speed to

meet the demand requirement for capacity.

The Outdoor Fan Control (Exchange Fan)

When adjusting the fan speed, the unit should remain at each

speed for 30+ seconds to avoid speed-change malfunctions.

In Cooling Mode, the wait time between speed levels should

be 15 seconds.

The Outdoor Fan Control When In Cooling or

Dehumidifying Mode

Five seconds after compressor starts, the outdoor fan will

start running at medium speed. After 30 seconds, it begins to

control the fans peed according to the temperature conditions

of the outdoor environment.

The Control of the Outdoor Unit Expansion Valve

When unit starts, the EEV valves will energize and change to a

standard opening. When operation starts, the EEV will change

position to keep the suction vapor superheat level at around

10°F.

When the unit is shut o the opening size of the expansion

valve of the indoor unit is 5 steps;

Four-Way Valve Control

For the details of defrosting four-way valve control, see the

defrosting process.

Under heating mode, the four-way valve opens. If the

compressor does not start or changes to a non-heating

mode, the compressor will be stopped for 2 minutes, and then

the four-way valve will shift.

Antifreezing Protection (Highwall Only)

Prevents freeze-up of the indoor coil

The indoor unit coil temperature sensor will shut o the

outdoor unit and begin a defrosting routine if the indoor coil

is below 32°F for more than 2 minutes. The indoor unit will

not report this operation. Once the indoor coil warms up, the

system will re-enter cooling mode and operate normally, This

protection cycle prevents the indoor coil from developing ice

coating during low heat load operation.

INTRODUCTION

A-9

ENGLISH

Functions and Control

Over-Temperature Heat Mode Indoor Coil

The over-temperature routine will protect the system from excessive high indoor coil temperature during heat mode operation.

The routine will initiate if the indoor coil temperature sensor reads temperatures in excess of 131F. Conditions that cause high

indoor coil temperature include indoor fan failure, dirty indoor coil and operating the system in heat mode when outdoor air

temperatures exceed operating limit. (Too warm outside)

Should this routine be initiated, the system will reduce compressor frequency until the indoor coil temperature reaches 117F.

Once this is achieved, the system will return to normal operation.

149°F

131°F

138°F

117°F

124°F

[This page intentionally left blank.]

OUTDOOR TECHNICAL OVERVIEW

B-1

ENGLISH

OUTDOOR TECHNICAL OVERVIEW

Components ......................................................................................................................................................................... B-2

Component Overview ......................................................................................................................................................... B-2

Service Monitor Board (SMB) .............................................................................................................................................. B-3

Inverter Power Module (IPM) ............................................................................................................................................... B-3

PCB ....................................................................................................................................................................................... B-4

Power Filter Board (PFB) ...................................................................................................................................................... B-5

Operations............................................................................................................................................................................ B-6

Cooling Mode Sequence of Operation ............................................................................................................................... B-6

Heating Mode Sequence of Operation ............................................................................................................................... B-8

Defrost Cycle Sequence of Operation ............................................................................................................................. B-10

Electronic Expansion Valve (EEV) Control ........................................................................................................................ B-11

4-Way Valve Heating Control ............................................................................................................................................ B-11

Compressor Sump Heater ................................................................................................................................................ B-11

Defrost Control .................................................................................................................................................................. B-12

Base Pan Heater Control Logic ......................................................................................................................................... B-12

Troubleshooting the Base Pan Heater Error .................................................................................................................... B-12

Discharge Sensor Protection ............................................................................................................................................ B-12

High Current Protection .................................................................................................................................................... B-13

High Pressure Protection in Cooling ................................................................................................................................. B-13

High Pressure Protection In Heating ................................................................................................................................ B-13

Low Pressure Protection ................................................................................................................................................... B-14

Oil Return Cycle ................................................................................................................................................................. B-15

Testing ................................................................................................................................................................................ B-16

Outdoor Fan Motor ............................................................................................................................................................ B-16

Temperature Sensor .......................................................................................................................................................... B-16

4-Way Valve ....................................................................................................................................................................... B-17

Electronic Expansion Valve (EEV) ..................................................................................................................................... B-17

Variable Speed Compressor ............................................................................................................................................. B-18

Wiring Error Check ............................................................................................................................................................. B-18

Wiring Diagrams ................................................................................................................................................................. B-19

DIP Switch Settings ............................................................................................................................................................ B-22

Error Codes ......................................................................................................................................................................... B-24

Table of Contents

2U20EH2VHA

3U24EH2VHA

4U36EH2VHA

OUTDOOR TECHNICAL OVERVIEW

B-2

ENGLISH

Topic TitleComponents

The outdoor unit features a variable speed, rotary type compressor that delivers refrigerant ow to up to 4 individual indoor

units. The system uses R-410A refrigerant mixed with PVE oil, and is 208/230 VAC, 60 Hz, single phase.

Compatible indoor units are High wall, Cassette, Ducted, and Console with remote control, cassette with either remote or wired

control, and ducted with wired control only.

The indoor units will maintain individualized room temperatures as set on each controller, provided all units are in the same

mode. If the rst unit to be turned on is set to the heating mode, all units will heat. If the rst unit to be turned on is set to the

cooling mode, all units will cool.

4-Way Valve

Accumulator

Compressor

Defrost Temperature Sensor

Discharge Temperature Sensor

Electronic Expansion Valves

Outdoor Ambient Temperature

Sensor

Outdoor Fan Motor

Power Factor Reactor

Suction Line Temperature Sensors

Terminal Block

Main Control Board

Module Control Board

Fan Blade

Base Pan Heater

Component Overview

OUTDOOR TECHNICAL OVERVIEW

B-3

ENGLISH

Topic TitleComponents

The SMB is connected to the PCB via connections CN-2 and CN-3.

The SW1 DIP switches are OFF (default position for normal operation).

The digital display will indicate operating frequency of the compressor when no

error code is present, or will ash an error code if present.

A solid green LED indicates that the A, B, C, D or E unit is successfully

communicating with the outdoor unit.

The SMB has important features including operational DIP switches, error code display, compressor speed, and diagnostic

capabilities.

The Inverter Power Module generates 3-phase VDC

power to operate the variable speed compressor. The

compressor is connected to the IPM via terminals U, V

and W.

A Reactor Coil is connected to the IPM at terminals

RI and RO. The Reactor Coil will lter electrical noise

generated at high frequency operation that could

cause damage to the compressor windings.

IPM generates a large amount of heat during operation.

This heat is transfered to a heat sink behind the board,

then mixed with the outdoor air. The Tm temperature

sensor protects the IPM from excessive temperatures.

Service Monitor Board (SMB)

Inverter Power Module (IPM)

2U & 3U

The Inverter Power Module generates 3-phase

variable VDC power(60V-230V) to operate the

variable speed compressor. The compressor is

connected to the IPM via terminals U, Vand W.

A Reactor Coil is connected to the IPM at terminals

LI and LO.The Reactor (spec is 5mH,25A/5mH);

the reactor is one part of the PFC(power factor

chopper circuit). Its main function is to boost

the DC bus voltage with the PFC switches IGBT.

The PFC circuit will improve the power factor

and reduce electromagnetic noise caused by

harmonics.

IPM generates a large amount of heat during

operation. This heat is transferred to a heat sink

behind the board, then mixed with the outdoor air.

The Tn temperature sensor is used to protects

the IPM from excessive temperatures.

OUTDOOR TECHNICAL OVERVIEW

B-4

ENGLISH

Components

Voltage to operate the PCB is provided by

the Power Filter Board on terminals ACN

and ACL.

When power is present, the Green LED

will light.

The communication cables to the PCB

from the Power Filter Board connect to

CN6 and CN34.

The Service Monitor Board connects

to plugs CN-23 and CN-8. When these

cables are connected to the Service

Monitor Board, the SMB digital display

should be illuminated.

Plug CN-21 connects the data path

between each indoor unit and the PCB .

The connections from this plug terminate

at the Number 3/C terminal at the indoor

unit voltage connection terminal strips.

The Outdoor Fan Motor is a DC voltage, variable speed type that connects to the PCB at terminal Plug CN-11.

The 4-Way Valve is energized by line voltage from a connection via Plug CN-5. This valve is energized in HEAT MODE.

The Crankcase Heater is energized via a connection at terminals CON-9 and CON-8 on the PCB.

The EEV coils for the outdoor unit and each indoor unit are connected at terminals CN-15 through CN-18. These EEV coils

include the connection for the HEAT MODE EEV coil.

There are a set of temperature sensors that monitor the temperature of the refrigerant entering and leaving each circuit.

These sensors are mounted in a group near the center of the circuit board.

There are system temperature sensors that monitor refrigerant line temperature and outdoor air temperatures. These

sensors plug into the PCB via Plugs CN-14, CN-1, CN-7, and CN-24.

The system has two refrigerant pressure switches, a Low Pressure Switch and a High Pressure Switch. These switches are

connected to the PCB via Plugs CN-12(HP) and CN-13(LP).

There are three sets of DIP switches. SW5 and SW7 aect the operational parameters of the unit. Refer to the wiring

diagram for the correct settings. SW6 positions are changed only when a Central Controller is used.

There are 4 surface mounted buttons located next to SW-5 and SW-6. These buttons are for factory use only.

The PCB has a Green LED and a Red LED. When power is present, the Red LED is on. When two or three indoor units are

connected, the Green LED is on.

T5A 250V rated ceramic fuse is located on the PCB. This fuse will open if excessive current occurs or if a power surge is

present. This fuse is eld replaceable.

Base pan heater connection (150W).

The PCB is connected via communication cables to the Inverter Power Module, Filter Board, and the Service Monitor Board.

14 3 8 17 7

912

PCB

OUTDOOR TECHNICAL OVERVIEW

B-5

ENGLISH

Components

A replaceable, 30A, 250V rated

ceramic fuse protects the outdoor

unit electronics. The fuse will open if

a power surge or internal short in the

outdoor unit has occurred.

The PFB receives line voltage at

terminals P1 and P2 from the outdoor

unit high voltage terminal block 1/N

and 2/L.

The voltage that powers the indoor

units connects to terminals P3 and P4.

The PCB receives power to operate

via connections at terminals P5 and

P6.

The IPM receives power via connections at terminals P7 and terminal 3.

There is a communication plug labeled CN-1 on the PFB. This plug connects from the PFB to the PCB. If this cable is

disconnected or loose, the system will generate a Code 6 module low or high voltage error. This error will not be displayed

in memory on the indoor unit wired controller. CN-1 and CN-2 connect to the PCB at terminals CN-6 and CN-34. CN-6 is

the low stand-by power connection. When power has been turned o at the controller for 5 minutes, CN-6 will remove the

12 VDC signal and open relay RL-1 on the PFB. This saves energy by shutting o power to the IPM. The capacitors must

have current ow before the compressor can start. CN-34 is the capacitor charging circuit. When the capacitors are fully

charged, the circuit opens to stop the charging process via the RL-2 relay. The voltage between the two pins of CN-1 and

the two pins of CN-2 is 12 VDC.

The purpose of the PFB is to lter out potential electrical noise before it reaches the outdoor unit electronic circuits. All voltage

to operate the outdoor unit circuits must pass through the PFB.

Power Filter Board (PFB)

2U & 3U

L1 & L2 is the input port of Filter Board,

they will provide 208/230Vac, 60Hz power

to the whole unit group(outdoor unit

&indoor unit ),as is shown in the wiring

diagram, these two terminal connect to the

OUD main power supply terminal block.

P1 & P3 is the one of the rst stage ltered

output of the Filter Board, they will provide

208/230Vac, 60Hz power to all the indoor

units which connect to the outdoor unit. As

is shown in the wiring diagram, these two terminals connect to one of the IDU & OUD connection terminal block.

P2 & P4 is the other one of the rst stage ltered output of the Filter Board, they will provide 208/230Vac, 60Hz power to

the main control board. As is shown in the wiring diagram, these two terminals connect to the ODU main control board CN2

L1 & L2 is the 2nd stage ltered output of the Filter Board, they will provide 208/230Vac, 60Hz power to the compressor

drive module (inverter board). As is shown in the wiring diagram, these two terminals compressor drive module’s power

input L1 & L2.

OUTDOOR TECHNICAL OVERVIEW

B-6

ENGLISH

Operations

On a call for cooling, the indoor unit will send the room temperature and set-point requirement to the outdoor unit PCB via the

data signal wire path. The data travels from the indoor unit to the outdoor unit via the wire located on terminal 3/C. The indoor

louvers will open and the indoor fan motor will start.

The outdoor unit will energize the EEVs that are controlling refrigerant ow to the calling indoor units. The position of the EEVs

will be set to an initial position based upon the outdoor air temperature.

The 4-way valve is de-energized. After a 3-minute time delay, the outdoor fan motor will be energized. Shortly after the outdoor

fan motor turns on, the compressor will start in low frequency. The operating frequency of the compressor will be displayed on

the Service Monitor Board .

The refrigerant in the system will begin to ow, and the compressor will discharge hot gas into the oil separator. Oil will be

trapped in the separator and returned to the suction inlet of the compressor via the capillary tube assembly low pressure path.

Comp-

ressor

ischarge temp.

●

sensor

Oil

separator

Capillary tube

Ø2.7*Ø1.0*1400

High pressure

switch

4-way valve

Pipe sensor

Toci

Suction temp.

sensor Ts

Low pressure

switch

Accumulator

Gas service valve

Outdoor

heat

exchanger

temp.

sensor

FAN-OUT

Outdoor

ambient

temperature

sensor Ta

Defrost

sensor Td

Distributor

Strainer

EEV O

Receiver

Liquid service valve

5/8

3/8

Unit A liquid pipe temp. sensor Tc2

Strainer

EEV A

Indoor unit A

Unit B liquid pipe temp. sensorTc2

Strainer

EEV B

Indoor unit B

Unit C liquid pipe temp. sensor Tc2

Strainer

EEV C

Indoor unit C

Unit A gas pipe temp. sensor Tc1

Unit

B gas pipe temp.

sensor Tc1

Unit C gas pipe temp. sensor Tc1

Indoor unit A

Indoor unit B

Indoor unit C

4-way valve coil:

OFF

Refrigerant flow in cooling

Refrigerant flow in heating

FAN-IN

Indoor

ambient

temperature

sensor

Indoor

heat

exchanger

temp.

sensor

Cooling Mode Sequence of Operation

OUTDOOR TECHNICAL OVERVIEW

B-7

ENGLISH

Operations

Temperature Sensor Td

The temperature of the compressor discharge hot gas will be

monitored by the Discharge Temperature Sensor. If the sensor

reads too hot or cool, the frequency/status of the operation

will be adjusted accordingly.

The hot gas will leave the oil separator and enter the 4-way

valve, which directs the hot gas to the outdoor coil. The

refrigerant will condense in the outdoor coil and be subcooled.

The refrigerant is now in a liquid state.

Temperature Sensor Toci

The temperature of the hot gas leaving the 4-way valve will be

monitored by the Toci Temperature Sensor. This temperature

should be near the temperature of the compressor discharge

gas temperature. If it is not, there is a problem with the 4-way

valve. The PCB will detect the temperature dierence and

generate an Error Code.

Temperature Sensor Tc

This sensor monitors the temperature of the outdoor

coil during condensing operation. If abnormal condensing

temperature is detected, the outdoor fan motor speed or

compressor frequency may be adjusted.

Temperature Sensor Ta

The outdoor air temperature will be monitored by the PCB.

If the outdoor air temperature rises or falls, the speed of the

outdoor fan may be changed.

Temperature Sensor Tc2

The Liquid Pipe Sensor will monitor the temperature of the

refrigerant leaving the EEV.

The low pressure low temperature refrigerant will enter the

mixed phase liquid line and travel to the indoor unit. Heat from

the indoor air passing across the evaporator coil will transfer

to the cold refrigerant, sending cool air into the space and

changing the liquid refrigerant into a cool vapor.

The cold vapor will travel down the vapor line and return to the

outdoor unit via a path through the gas stop valve.

Temperature Sensor Tc1

The Gas Pipe Sensor will monitor the temperature of the

gas pipe to calculate the dierence between Liquid Pipe

Temperature and Gas Pipe Temperature. If a change in

EEV port opening size is needed, the EEV will make a small

adjustment.

The vaporized refrigerant enters the 4-way valve and travels

to the vapor line accumulator. The accumulator will trap any

liquid refrigerant if present to prevent it from entering the

compressor.

The vapor will exit the accumulator and enter the compressor.

This cycle will repeat until the demand for cooling ends.

Temperature Sensor Ts

The temperature of the suction gas entering the compressor

is monitored by the Suction Temperature Sensor. Before

stopping operation, the EEV may open to feed more

refrigerant or close to warm up the line.

The demand becomes less as the indoor temperature drops

toward the desired temperature, so the compressor will

reduce speed. When the set temperature is reached, the

compressor and outdoor fan will shut o. The circulating fan

of each indoor unit continues to run.

OUTDOOR TECHNICAL OVERVIEW

B-8

ENGLISH

Operations

Comp-

ressor

ischarge temp.

●

sensor

Oil

separator

Capillary tube

Ø2.7*Ø1.0*1400

High pressure

switch

4-way valve

Pipe sensor

Toci

Suction temp.

sensor Ts

Low pressure

switch

Accumulator

Gas service valve

Outdoor

heat

exchanger

temp.

sensor

FAN-OUT

Outdoor

ambient

temperature

sensor Ta

Defrost

sensor Td

Distributor

Strainer

EEV O

Receiver

Liquid service valve

5/8

3/8

Unit A liquid pipe temp. sensor Tc2

Strainer

EEV A

Indoor unit A

Unit B liquid pipe temp. sensorTc2

Strainer

EEV B

Indoor unit B

Unit C liquid pipe temp. sensor Tc2

Strainer

EEV C

Indoor unit C

Unit A gas pipe temp. sensor Tc1

Unit

B gas pipe temp.

sensor Tc1

Unit C gas pipe temp. sensor Tc1

Indoor unit A

Indoor unit B

Indoor unit C

4-way valve coil:

OFF

Refrigerant flow in cooling

Refrigerant flow in heating

FAN-IN

Indoor

ambient

temperature

sensor

Indoor

heat

exchanger

temp.

sensor

On a call for heating, the indoor unit will send the room temperature and set-point requirement to the outdoor unit PCB via the

data signal wire path. The data travels from the indoor unit to the outdoor unit via the wire located on terminal 3/C. The indoor

unit louvers will open. The fan will not start until the coil has warmed suciently to avoid cold drafts.

EEVs serving indoor circuits will step to the standard opening. The outdoor EEV opens to a position based upon the outdoor air

temperature.

The 4-way valve will energize and the outdoor fan will start. The compressor starts at a slow speed and will increase based upon

demand. The indoor fan starts after the indoor coil is warm enough to avoid circulating cool air.

With the compressor operating, refrigerant will begin to ow throughout the refrigeration circuit.

The operating frequency of the compressor will be displayed on the Service Monitor Board.

When the compressor starts, hot gas will ow into the oil separator. Oil will be trapped in the separator and returned to the

suction inlet of the compressor via the capillary tube assembly low pressure path.

Heating Mode Sequence of Operation

OUTDOOR TECHNICAL OVERVIEW

B-9

ENGLISH

Operations

Temperature Sensor Td

The temperature of the compressor discharge hot gas will be

monitored by the Discharge Temperature Sensor. If the sensor

reads too hot or cool, the frequency/status of the operation

will be adjusted as needed.

The hot gas will leave the oil separator and enter the 4-way

valve. The 4-way valve will direct the hot gas to ALL of the

indoor coils.

Note: Any indoor unit that is in heating mode will have it’s

louver open and indoor fan running. Non-calling indoor units

will receive hot gas but their fans will remain on very low speed

with the louver open. When demand for heat increases, the

indoor fan will speed up to meet the increased demand.

Temp. Sensor Tc1 & Indoor Heat Exchanger Temp. Sensor

The temperature of Tc1 should now be hot. This will indicate

the 4-way valve is directing hot gas to the indoor coils. If it

is not, there is a problem with the 4-way valve. The PCB will

detect the temperature dierence and generate an Error

Code.

The indoor heat exchanger temperature sensor will monitor

the temperature of the indoor coil to ensure it is hot enough to

prevent blowing cold air. Once adequately warm temperature

is sensed at the indoor coil, the PCB will increase the fan speed

if needed to meet the demand.

The hot gas entering the indoor coil will condense into a

saturated mix and then be subcooled. The refrigerant will

return to the outdoor unit via the liquid line.

Temperature Sensor Tc2

This sensor monitors the temperature of the refrigerant liquid

returning from the indoor coil. The indoor EEV opening angle

is xed.

The liquid will enter the Liquid Line Strainer and will pass

through the OPEN EEV.

The refrigerant liquid now enters a receiver where excess

refrigerant will store.

After the liquid leaves the Liquid Receiver, it will enter the

restriction of the OUTDOOR UNIT’s EEV, which changes the

liquid refrigerant to a lower pressure and temperature as it

enters the outdoor coil.

As the outdoor coil absorbs heat from the surrounding air, the

very cold liquid refrigerant is changed to a cool vapor. This

vapor travels through the 4-way valve to the accumulator.

Temperature Sensor Te

The outdoor coil temperature will be sensed by the Defrost

Sensor. The sensor will use this temperature to to adjust EEV

open angle and to calculate when a defrost cycle is necessary.

Temperature Sensor Toci

This temperature sensor is now sensing the suction line

temperature of the refrigerant vapor leaving the outdoor coil.

This temperature is used to adjust the EEV open angle.

The vapor refrigerant will then enter the 4-way valve and

be directed to the compressor suction accumulator. The

accumulator will prevent any remaining liquid refrigerant from

entering the compressor.

The vapor will exit the accumulator and enter the compressor.

This cycle repeats until the demand for heating ends.

Temperature Sensor Ts

The temperature of the suction gas entering the compressor

is monitored by the Suction Temperature Sensor.

As the demand becomes less while the indoor temperature

rises toward the desired temperature, the compressor will

reduce speed. When the set temperature is reached, the

compressor and outdoor fan will shut o. The circulating fan

of each indoor unit continues to run.

OUTDOOR TECHNICAL OVERVIEW

B-10

ENGLISH

Operations

Beginning end

Fixed frequency Indicated FQY 60s Defrosting FQY 80 Hz（E） 60s Soft startup

Compressor

0HZ 0HZ

Outdoor motor ON Send defrosting signal to indoor Auto

OFF

4-way valve ON

OFF 15s

450-pulse 450-pulse

350-pulse(E)

All EEVs Auto open angle Auto open angle

All indoor motors ON

OFF Anti- cold air fun ction

Multi:

Defrost Cycle Sequence of Operation

OUTDOOR TECHNICAL OVERVIEW

B-11

ENGLISH

Operations

Electronic Expansion Valve (EEV) Control

Electronic characteristics

Max. open angle 480 pulses

Driving speed PPS

Open angle limitation of EEV

Unit stop Max. open angle Thermostat OFF Min. open angle

Cool/ dry 5 pulses 480 pulses 5 pulses 80 pulses

Heat 5 pulses 480 pulses 50 pulses 80 pulses

The EEV routinely opens and closes to maintain the compressor discharge temperature within an acceptable range.

ompressor ON

OFF

-way valve ON

OFF

50S

2 minutes and 55s

4-Way Valve Heating Control

When the compressor starts in the heating mode, there is a 1-minute delay before power is applied to the 4-way valve to switch

the ow of hot refrigerant to the indoor coil. When the call for heat is satised and the compressor shuts o, a 3-minute delay will

occur before the 4-way valve is powered down and switches back to the at-rest (cooling) position.

If the 4-way valve does not switch into the heating mode, after 15 minutes of compressor run time and the indoor coil

temperature is below 41°F/5°C, the compressor will stop and the unit will display a 17-ash error code on the outdoor PCB.

Compressor Sump Heater

The sump (crankcase) heater keeps refrigerant at a higher temperature than the coldest part of the system. This prevents

refrigerant from mixing with the compressor oil and also dries condensed refrigerant inside the sump. The sump heater will be

energized when the ambient temperature is below 81°F/27°C and will be o when the ambient is 90°F/32°C.

Heater OFF Heater ON*min

Ta>50

F(10

C) OR Td>=68

F(20

C) 0 0

F(5

C<Ta ≤50

F(10

C)and Td<68

F(20

C) 50%*60min 50%*60min

F(0

C)<Ta ≤41

F(5

C)and Td<68

F(20

C) 33%*60min 66%*60min

F(0

C)>=Ta andTd<68

F(20

C) 0 100%*60min

OUTDOOR TECHNICAL OVERVIEW

B-12

ENGLISH

Operations

Base Pan Heater Control Logic

When the compressor starts in the heating mode, the

following conditions will apply:

Troubleshooting the Base Pan Heater Error:

Step 1:

Check the pan heater for an open circuit or shirt circuit.

Unplug the connector from main control PCB. Test the

resistance between the two pins of the pan heater connector.

It should be 0.28-0.379KΩ. If out of range, change the pan

heater. If normal go step 2.

Step 2:

Check the main control board pan heater output port . Unplug

the connector from main control PCB. Run the ODU with

manually forced heating (Set the display board SW 1-1 as

ON). Test the voltage between the two heater output pins, it

should be 208-230Vac.

Defrost Control

In the heating mode and along with the ambient sensor, the

defrost sensor monitors the temperature of the outdoor

coil to determine if defrost is needed. If the compressor has

been running for 10 minutes continuously and for 45 minutes

overall, the dierence between the ambient sensor (Ta) and

the defrost sensor (Te) will be checked. The system will

initiate the defrost cycle if the following conditions can be met

for 5 continuous minutes:

Te ≤ C x Ta-A

Te: Defrost temperature sensor

Ta: Ambient temperature

C: 0.80 if Ta < 32°F/0°C, 0.60 if Ta ≥ 32°F/0°C

A: 8, moderate climate (factory setting). 6, severe climate

(alternate setting)

End Defrosting:

If the defrost sensor (Te) detects the temperature of the

outdoor coil is above 44°F(7°C) for 60 seconds or is above

54°F(12°C) for 30 seconds, the defrost cycle will terminate. If

these temperatures cannot be reached, the defrost cycle will

automatically terminate in 10 minutes.

Timed Defrost Option:

• When the outdoor ambient temperature sensor detects Ta

is less than 32°F(0°C)

• In heating mode, compressor runs continuously for 60

minutes or for 240 minutes in all

• When the above conditions are met, the system will defrost.

Defrosting frequency is 68 HZ, with a defrosting time of 8

minutes.

Outdoor Temperature Pan Heater

>37

F(3

C) OFF

F(-2

C) to 34

F(1

C) OFF 20min. ON 10min.

F(-12

C) to 25

F(-4

C) OFF 15min. ON 15min.

<10

F(-12

C) ON

Discharge Sensor Protection

If the discharge temperature is higher than normal, the compressor will slow down to lower the temperature.

℃

Multi:

Discharging temp. Td

Reduce FQY rapidly 1HZ/S

Reduce FQY slowly 1HZ/10S

Remain FQY

Increase FQY slowly 1HZ/10S

Remain FQY

If the discharge temperature sensor reaches 243F for 10

seconds, the compressor will shut off. After the 3-minute

time delay, the compressor will restart. If this occurs

three times in a 60-minute period, the compressor will

lock out. Until the cause of the high temperature is

discovered, the compressor will not restart until the

power is interrupted then restored.

203℉( 95℃)

207℉( 97℃)

225℉( 107℃)

234℉( 112℃)

243℉( 117℃)

OUTDOOR TECHNICAL OVERVIEW

B-13

ENGLISH

Operations

High Current Protection

The below table is the outdoor unit protection current and compressor current.

If the temperature reaches 150

F(66

C) three times in one hour, the

system will lock out. Reset by turning power o and back on.

Reduce FQY rapidly 2Hz/S

Reduce FQY rapidly 1Hz/S

Reduce FQY rapidly 1Hz/10S

Remain FQY

Reduce FQY slowly 1Hz/S

100%*I

98%*I

96%*I

90%*I

88%*I

Remain FQY

Model Maximum current (I) Compressor current (CT)

2U20EH2VHA 12.5A 10A

3U24EH2VHA 13.5 14A

4U36EH2VHA

??? ???

High Pressure Protection in Cooling

If there is an abnormal stop 3 times in 1 hour, the unit

will turn o. Turn o and restore power to clear error.

Reduce FQY rapidly 2Hz/S

Reduce FQY slowly 1Hz/S

Remain FQY

Raise FQY slowly 1Hz/10S

131

F(55

Tc--cooling

138

F(59

144

F(62

147

F(64

150

F(66

Remain FQY

If the temperature reaches 158

F(70

C) three times in one hour,

the system will lock out. Reset by turning power o and back on.

Reduce FQY rapidly 2Hz/S

Reduce FQY slowly 1Hz/S

Remain FQY

Raise FQY slowly 1Hz/10S

129

F(54

Tc--heating

135

F(57

138

F(59

145

F(63

158

F(70

Remain FQY

High Pressure Protection In Heating

OUTDOOR TECHNICAL OVERVIEW

B-14

ENGLISH

Operations

Low Pressure Protection

With the compressor running, if the low pressure switch opens for 1 minute, the compressor will stop.

If this condition occurs 3 times in an hour, the compressor will lock out and a low pressure error code will be displayed at the

indoor unit.

If the compressor is not running and the switch opens for 30 seconds, a low pressure error code will be displayed.

The low pressure switch does not stop compressor operation or signal an error code during the following conditions:

• The rst 8 minutes of run time when the compressor starts a new cycle

• During defrost

• When the ambient temperature is below 32°F/0°C

• Following the termination of an oil return cycle

When any of the above 4 conditions are present, low pressure protection is provided by the coil temperature sensors in both

heating (Te) and cooling (Tc2) modes.

Operate normally

Min. running FQY 20Hz

LP OFF & FQY 20Hz

LP ON & FQY 20Hz

Raise FQY slowly 1Hz/10S

-49

F(-45

Tc 2

-40

F(-40

-31

F(-35

-22

F(-30

-13

F(-25

Low Pressure Protection in Heating Mode:

Operate normally

Min. running FQY 20Hz

LP OFF & FQY 20Hz

LP ON & FQY 20Hz

Raise FQY slowly 1Hz/10S

-49

F(-45

-40

F(-40

-31

F(-35

-22

F(-30

-58

F(-45

Low Pressure Protection in Cooling Mode:

OUTDOOR TECHNICAL OVERVIEW

B-15

ENGLISH

Operations

Send oil return signal oil return begins oil return over

60s ref. eliminated 30s

Oil return frequency auto frequency

Low frequency

Inverter compressor auto frequency

350 pulses(E)

running indoor EEV auto angle auto angle

120 pulses(E)

80(E)

stopped indoor EEV OFF angle 5(E) OFF angle 5(E)

Outdoor motor AUTO AUTO (TC or ambient temp. control) AUTO

running indoor motor AUTO AUTO (set fan speed) AUTO

stopped indoor motor STOP STOP STOP

4-way valve OFF OFF OFF

Oil Return in Cooling Mode:

Oil Return Cycle

When the compressor is operating at low load

conditions, or the operating frequency has

been below 70Hz continuously for 4 hours,

the system will enter the oil return cycle. This

ensures that oil which may be trapped within

the system at low loads will return to the

compressor crankcase.

If a 4-hour low speed run time has occurred,

the oil return procedure initiates by

automatically ramping up the compressor

speed to at least 85Hz for a pre-set time, up

to a 9-minute maximum. The higher speed

will wick hiding oil into the now faster-moving

refrigerant and deposit it in the compressor

crankcase. To avoid occupant discomfort

when the oil return cycle is active, the indoor

fan shuts o.

Should an error code result in a system

shutdown, the oil return cycle timing will

resume when the error code has been cleared.

＆ ‐ ＞ ℉（℃）

‐ ＞ ℉（℃）

＜

Oil Return Exit Conditions, Heating:

‐ ＜

＆ ‐ ＜

Send oil return signal oil return begins oil return over

Inverter compressor indicated FQCY 60s oil return FQCY 60s soft startup

0HZ 0HZ

Outdoor motor AUTO AUTO

AUTO (TC control)

4-way valve ON

OFF 15s

450 pulses 450 pulses

350 pulses

All expansion valves auto angle auto angle

Indoor fan motor ON

OFF Cold air proving mode

℉（℃）

℉(℃)

＆ ‐ ＞ ℉（℃）

‐ ＞ ℉（℃）

＜

Oil Return Exit Conditions, Heating:

Max. 9 minutes (E)

OR OR Td Tc‐ ＜ for 30s continuously(5 minutes later, begin

to count)

＆ Ts Tc2AVE‐ ＜ for 30s continuously(5 minutes later,

begin to count)

Running for min. 5 minutes

℉（℃）

68℉(20 ℃)

59℉(15 ℃)

Oil Return Exit Conditions, Cooling:

1 minute later after oil return is over

＆ Td Tc‐ ＞86℉（30 ℃）

OR OR Ts Tc2AVE‐ ＞86℉（30 ℃）

Tc2AVE＜

Max. 10 minutes

‐ ＜

＆ ‐ ＜

-31℉（-35 ℃）

℉(℃)

Oil Return in Heating Mode

Oil Return in Cooling Mode

OUTDOOR TECHNICAL OVERVIEW

B-16

ENGLISH

Testing

Outdoor Fan Motor

Check that the wiring and plug connections are in good condition.

If the outdoor unit fan motor does not run, or the Service Monitor Board indicates an error

code of 09, check the following voltages at the motor connector on the outdoor unit PCB. Set

the meter to read DC volts with a minimum voltage range of 350 volts. All voltage values are

approximate. Initiate forced cooling.

1. DC voltage between the Red and Black wire connnections should read 310 ~ 334 VDC. This

is the main voltage for powering the fan motor.

2. DC voltage between the White and Black wire connnections should read 15VDC. This is the

voltage for powering the electronic circuit of the fan motor.

3. DC voltage between the Yellow and Black wire connnections should read 4VDC. The voltage

will read 0VDC when the fan is not being called to operate. This is the control voltage for

regulating the speed of the fan motor.

4. DC voltage between the Blue and Black wire connnections should read 8VDC. The voltage

will read 14VDC when the fan is not being called to operate. (This is the feedback voltage to

the PCB for determining the speed of the fan motor)

If the outdoor fan initially runs, increases speed then stops, and the Service Monitor Board

indicates an error code of 09, the feedback circuit is not functioning. Check that the wiring and

plug connections are in good condition.

Outdoor Fan 310VDC

Pins 1 - 3

Outdoor Fan 15VDC

Pins 3 - 4

Outdoor Fan Control

Pins 3 - 5

Outdoor Fan Feedback

Pins 3 - 6

Temperature Sensor

The temperature sensors are negative coecient thermistors, in which resistance

decreases as temperature rises. Should the sensors fail, the PCB will generate an

appropriate error code.

To check the calibration of the sensors:

1. Shut o power to the outdoor unit.

2. Disconnect the sensor at the circuit board plug.

3. Measure the temperature of the air surrounding the sensor.

4. Measure the electrical resistance of the sensor using needle probes. Do not

force standard probes into the sensor plug.

5. Compare the measured resistance of the sensor against the resistance/

temperature specications (See chart in reference section)

6. If the sensor resistance is outside of the specication tolerances shown on the

resistance/temperature table, replace the sensor.

DC Motor

+310 VDC

DC Ground

+15 VDC

Signal

Feedback

Red

Black

White

Yellow

Blue

OUTDOOR TECHNICAL OVERVIEW

B-17

ENGLISH

Testing

4-Way Valve

The 4-way valve will control the direction of hot gas discharge via

an internal slide assembly. The valve has a line voltage solenoid

that is energized in heat mode. The solenoid will direct the internal

slide to send the hot gas to the indoor coil. During cooling mode

de-energized operation, the internal slide will direct compressor

hot gas to the outdoor coil.

4-way valves may have a failure of the electrical solenoid that

prevents the valve from shifting, or they may become stuck due to

debris lodging inside the valve body. If the valve fails to direct the

hot gas in the proper direction, temperature sensors within the

outdoor unit will detect the problem and generate an error code.

If the valve fails to shift the hot gas to the proper coil, or it only

partially shifts, perform the following:

1. Check for correct refrigerant charge, and that all other operating parameters have been met.

2. In the heating mode, the solenoid will shift after a short time delay. Check for line voltage to the solenoid coil.

3. If the valve has voltage but fails to shift the hot gas to the indoor coil, shut the system down and unplug the 4-way valve from

the PCB plug.

4. Use an ohmmeter to check continuity through the solenoid coil. The coil resistance should be 2.1k Ohms. If a winding shows

open or shorted, the solenoid coil will have to be replaced.

5. If the coil resistance is within the tolerance, use a magnet along the valve body to determine the location of the piston. If one

end of the piston is against the end of the valve body, it is stuck and the valve must be replaced.

6. Partial shifting of the valve can be detected by measuring the temperature of the suction gas where it enters the reversing

valve and then comparing that temperature to the temperature of the suction gas exiting the 4-way valve. There should be

no more than a 13°F dierence. Excessive temperature rise through the suction gas path is an indication of a stuck piston. If

the piston will not become free by switching from heating to cooling several times, a slight tapping on the valve body, or by

using a powerful magnet, the valve will require replacement.

12VDC

EEV Terminals

Electronic Expansion Valve (EEV)

EEV (6-pin, 6 wire)

White Yellow Orange

Blue Brown Red

White - OL 92 Ω OL 46 Ω OL

Yellow - - OL 92 Ω OL 46 Ω

Orange - - - OL 46 Ω OL

Blue - - - - OL 46 Ω

Brown - - - - - OL

Red - - - - - -

EEV (6-pin, 5 wire)

White Yellow Orange

Blue X Red

White - 92 Ω 92 Ω 92 Ω - 46 Ω

Yellow - - 92 Ω 92 Ω - 46 Ω

Orange - - - 92 Ω - 46 Ω

Blue - - - - - 46 Ω

X - - - - - -

Red - - - - - -

1. Check to see if the Electronic expansion valve (EEV) connector is correctly and rmly inserted in the PCB.

2. Turn the power o and back on again,

3. Check to see whether the EEV have a reposition sound. This sound will start after approx 2 min. If the EEV doesn’t have noise,

please disconnect the connector and check the resistance (refer to resistance tables below).

4. If the resistance is OK, The PCB may be at fault.

OUTDOOR TECHNICAL OVERVIEW

B-18

ENGLISH

Topic TitleTesting

Variable Speed Compressor

1. Begin by turning o power at the equipment disconnect switch. Adequate time must be given for capacitors on the circuit

board to discharge. Wait a minimum of 12 minutes before handling the circuitry.

2. Locate the Inverter control module (IPM). The IPM is connected to the main circuit board by a wire harnesses, and has the

compressor connections mounted on it.

3. Set your test meter to AC volts and test for voltage at the three compressor connections. Voltage should be zero before

proceeding.

4. Remove the three compressor connections making note of the terminal letter and the wire colors.

5. Set your ohm meter to the lowest resistance setting that is available. Test all three connections terminals using the following

sequence:

• U terminal to V terminal

• U terminal to W terminal

• V terminal to W terminal

All three resistance values should match the specication table below. Compressor windings are deemed bad if they are

greater than 7% out of specication. Readings taken at the wire IPM module that are outside of factory tolerances require

steps 6 through 9.

6. Remove the compressor blanket and set it aside. Remove the terminal block cover to expose the connections at the

compressor terminals. Inspect for any visual damage. Remove all three wires from the terminals making note of the wire color

and the terminal identier.

7. Repeat process outlined in step 5. Repair or replace the wires if the compressor windings check properly.

8. Check each terminal to ground (suction line connection at compressor) to check for grounded windings if the resistance

values are not correct.

9. Replace the compressor if the winding measurements are greater than 7% out of specication.

Wiring Error Check

1. Disconnect power to

the outdoor unit.

2. Set Dip Switches

SW1-1, SW1-2,

SW1-3 & SW1-4 to

the ON position.

These dip switches

are located on the

Service Monitor

Board.

3. Turn ON power to the outdoor unit.

4. All indoor fans will be set to HIGH fan speed.

5. EEV for Circuit A will open. All other EEV’s will close.

6. After a 3 minute delay, the Compressor will start and ramp

up to 55HZ.

7. The digital display with alternately display “CH” and

“Compressor Frequency (HZ)” at 5 second intervals

8. The system will circulate refrigerant through Circuit A for

approximatley 10 minutes.

9. Afterwards, Circuit A’s EEV will close and Circuit B’s EVV

will open.

10. This process will be repeated for each indoor unit that is

connected.

11. Once all indoor units have

been checked, the digital

display will display either

“EC” or “0”. “EC” indicates

a communication error

between the outdoor and

indoor unit. The LED(s) will

be ashing, indicating which

circuit has the fault

12. Once the wiring is corrected, re-run this test to conrm

everything is functional.

13. “0” indicates that all wiring is

correct.

14. If all wiring is correct, the

LED’s remain solid lit.

15. Once the test is complete,

make sure to change the dip

switches back to the OFF

position, and set each indoor

unit to preferred set points.

OUTDOOR TECHNICAL OVERVIEW

B-19

ENGLISH

Topic TitleWiring Diagrams

2U20EH2VHA

1 2 3 4 5 678

SW3

SW4

SW2

SW1

CN12

CN13

CN9

GND

CN11

CON8

CN8

CN5

TO Module

LED_G

LED_R

CN6

4-WAY VALVE

DC-FAN

MOTOR

250VAC T5A

FUSE

CON9

Vsp

Vcc

CN25

CN16

ACN

ACL

4321

Vdc

L1 L2

Power

CN2

CN23

CN21

SW6

SW5

COMPRESSOR

CN17

CN15

CRANKCASE HEATER

Definition of SW6

OFF

OFF OFFON

ON ON

Centralized Control

Address=1

Address=2

Address=16

---------------

---- ---- ---- ----

Definition of SW1

SW1-1

SW1-2

SW1-3

SW1-4

Normal Operating(Default)

OFF

ON OFF

Force Heating

Force Cooling

Rated Operating

To Indoor

Unit B

OR: Orange B: Black BL: Blue GR:Green R: Red

Y/G: Yellow/Green W: White Y: Yellow BR: Brown

E.E.V:Electro expansion valve

LP/HP:Low /high pressure switch

Toci: Outdoor Condensing inlet Temp. sensor

Tc: Outdoor Condensing Temperature Sensor

Ts: Compressor Suction Temp. Sensor

Ta: Ambient Temp. Sensor

Td: Compressor Discharge Temp. Sensor

Te: Defrosting Temp. Sensor

Tm: Module Temp. Sensor

Tc1(a/b/c/d/e):Condensing Temp. Sensor

for Indoor Units a/b/c/d/e (Gas Pipe)

Tc2(a/b/c/d/e):Condensing Temp. Sensor

for Indoor Units a/b/c/d/e (Liquid Pipe)

P2(N)

F30A 250VAC

FUSE

P1(L)

RL1

4321

CN2

CN3

CN1

CN4

SW1

4321

1 2 3 4 5 678

SW7

0150530741

To Indoor

Unit A

To central

Controller

OFF

Time Defrost Valid

CN1

BL Y W

2U20EH2VHA

SW5

4 5

SW7

4 5

Default setting

of SW5 & SW7

Y/G

Electrolytic

Capacitor

Reactor

ACN

N(-)

P(+)

ACL

CN15

CN8

CN11

CN2

CN34

CN4

BL BL

GRAY

Base Pan Heater

CN14

CN1 CN24

BA BA

TC1

TC2

Toci

CN7

CN17

E.E.V-O

E.E.V-A

E.E.V-B

The dashed part is optional.

Inverter Power

Module

MAIN฀฀฀CONTROL฀฀BOARD

POWER

FILTER฀

BOARD

PMV-RE PMV-A

PMV-B

OUTDOOR TECHNICAL OVERVIEW

B-20

ENGLISH

Topic TitleWiring Diagrams

1 2 3 4 5 678

SW3

SW4

SW2

SW1

CN12

CN13

CN9

GND

CN11

CON8

CN8

CN5

TO Module

MAIN฀฀฀CONTROL฀฀BOARD

LED_G

LED_R

CN6

4-WAY VALVE

DC-FAN

MOTOR

250VAC T5A

FUSE

CON9

Vsp

Vcc

CN25

CN16

ACN

ACL

4321

Vdc

L1 L2

Power

CN2

CN23

CN21

SW6

SW5

COMPRESSOR

CN17

CN18

CN15

CRANKCASE HEATER

Definition of SW6

OFF

OFF OFFON

ON ON

Centralized Control

Address=1

Address=2

Address=16

---------------

---- ---- ---- ----

Definition of SW1

SW1-1

SW1-2

SW1-3

SW1-4

Normal Operating(Default)

OFF

ON OFF

Force Heating

Force Cooling

Rated Operating

To Indoor

Unit C

To Indoor

Unit B

OR: Orange B: Black BL: Blue GR:Green R: Red

Y/G: Yellow/Green W: White Y: Yellow BR: Brown

E.E.V:Electro expansion valve

LP/HP:Low /high pressure switch

Toci: Outdoor Condensing inlet Temp. sensor

Tc: Outdoor Condensing Temperature Sensor

Ts: Compressor Suction Temp. Sensor

Ta: Ambient Temp. Sensor

Td: Compressor Discharge Temp. Sensor

Te: Defrosting Temp. Sensor

Tm: Module Temp. Sensor

Tc1(a/b/c/d/e):Condensing Temp. Sensor

for Indoor Units a/b/c/d/e (Gas Pipe)

Tc2(a/b/c/d/e):Condensing Temp. Sensor

for Indoor Units a/b/c/d/e (Liquid Pipe)

P2(N)

POWER

FILTER฀

BOARD

F30A 250VAC

FUSE

P1(L)

RL1

4321

CN2

CN3

CN1

CN4

SW1

4321

1 2 3 4 5 678

SW7

0150530715

To Indoor

Unit A

To central

controller

OFF

Time Defrost Valid

CN1

BL Y W

3U24EH2VHA

SW5

4 5

SW7

4 5

Default setting

of SW5 & SW7

Y/G

Electrolytic

Capacitor

Reactor

ACN

N(-)

P(+)

ACL

CN15

CN8

CN11

CN2

CN34

CN4

GRAY

Base Pan Heater

CN14

CN1 CN24

TC1

TC2

Toci

CN7

CN17

PMV-RE

PMV-A

PMV-B

PMV-C

E.E.V-O

E.E.V-A

E.E.V-B

E.E.V-C

The dashed part is optional.

Inverter Power

Module

3U24EH2VHA

OUTDOOR TECHNICAL OVERVIEW

B-21

ENGLISH

Topic TitleWiring Diagrams

4U36EH2VHA

CN9

GND

CN11

CON8

CN5

MAIN CONTROL BOARD

4-WAY

VALVE

DC FAN

MOTOR

250VAC T5A

FUSE

CON9

Vsp

Vcc

ON ON

Vdc

L1 L2

Power supply

CN2

SW7

COMPRESSOR

CN15

CRANKCASE

HEATER

POWER FILTER

BOARD

BL Y W

Y/G

Reactor

CN6

CN4

GRY

BASE PAN

HEATER

CN1 ( TC1)

CN24( TC2)

E.E.V-O

E.E.V-A

E.E.V-B E.E.V-C

DRIVE MODULE

T20A/250VAC

COMM.

fin

CN14

CN13

E.E.V-D

CN16 CN17 CN18 CN19

CN8

To Indoor

Unit A

CN23

CN21

To Indoor

Unit B

To Indoor

Unit C

To Indoor

C B A

D C B A

LED2

SW6 SW5

U V W

SERVICE

DISPLAY

BOARD

A B

CN3

CN2

CN4

Sensor abbreviation :

Tc: Condensing Temp.

Ts: Compressor Suction

Temp.

Ta: Ambient Temp.

Td: Compressor Discharge

Te: Defrosting Temp.

Tfin: Module Temp.

TC1:Condensing Temp.

for Indoor Units A/B/C/D

Toci: Outdoor

Condensing inlet Temp.

Other abbreviation:

OR: Orange,Y/G:

Yellow/Green,W: White,

Y: Yellow, BR: Brown,

B: Black, BL: Blue,

GR:Green ,GRY:GREY

R: Red E.E.V:Electro

expansion valve,

LP/HP:

Low /high pressure switch

Note:

1.Dashed parts are

optional.

2.Please refer to

service manual to get

details of the DIP

switches .

3.Do not change the

DIP switches setting

without technical

support.

4.The LED1-LED5 in

the service display

board in turn

corresponds to the

communication status

of ndoor unitA,B,C,D.

LED will not lit if

communication

abnormal.

SW1 SW2 SW3 SW4

Start/+

Stop/-

Y/G

EARTH

L1 L2

L1’

(Gas Pipe)

TC2:Condensing Temp.

for Indoor Units A/B/C/D

(Liquid Pipe)

Definition of Dispaly board SW1

SW1-1

SW1-2

SW1-3

SW1-4

Normal Operating(default)

OFF

ON OFF

Manually forced Heating

Manually forced Cooling

Rated Operating（fixed speed）

OFF

Time Defrost Valid

4U36EH2VHA1

SW5

4 5

SW7

4 5

Factory defaultof main control board SW5 & SW7

Unit D

Remote

central

controller

0150538688

LED1

Other detail s about the service information please please refer to technical service mannual.

Centralized control address

SW6-1

SW6-2

SW6-3

SW6-4

OFF

Definition of main control board SW6

Indoor unit address group1

( NO.1-NO.5) (default)

OFF

OFF OFF

Indoor unit address group2

( NO.6-NO.10)

……

ON ON

Indoor unit address group

16( NO.76-NO.80)

5V(V+)

COM

GND

Toci

CN7

W R R

pin1

IDU&ODU Wiring Error Check

MAIN side pin1-DISPLAY side pin5

pin1

SW1

LED5

SMG1

Means switch at ON position

Means switch at OFF position

pin1

ACL(L1)

ACL(L2)

CN12

L2’

T20A/250VAC

LED4

LED3

LED2

LED1

FAN

OUTDOOR TECHNICAL OVERVIEW

B-22

ENGLISH

Topic TitleDIP Switch Settings

Description SW5-1 SW5-2 SW5-3 SW5-4 SW5-5 SW5-6 SW5-7 SW5-8

Heat pump OFF* ---- ---- ---- ---- ---- ---- ----

Cooling only ON ---- ---- ---- ---- ---- ---- ----

Defrost temp. selection (used for mild weather

defrost)

---- OFF* ---- ---- ---- ---- ---- ----

Defrost temp. selection (used for severe weather

defrost)

---- ON ---- ---- ---- ---- ---- ----

Power input restrict

invalid ---- ---- OFF* ---- ---- ---- ---- ----

Power input restrict valid ---- ---- ON ---- ---- ---- ---- ----

2U20EH2VHA ---- ---- ---- OFF ON ON ---- ----

3U24EH2VHA ---- ---- ---- ON ON OFF ---- ----

Factory use only ---- ---- ---- ---- ---- ---- OFF* ----

Factory use only ---- ---- ---- ---- ---- ---- ON ----

Quiet operation valid ---- ---- ---- ---- ---- ---- ---- OFF*

Quiet operation invalid ---- ---- ---- ---- ---- ---- ---- ON

Note:

1. Power input restrict selection: OFF-invalid; ON-valid(≤3500W)

2. Quiet operation: If OFF, the outdoor unit will calculate and obtain the average ambient temperature of the unit within the

last 24 hours, Tao_average_24. Then compare the current ambient temperature with the ambient temperature average

Tao_average_24, and combine it with the previous ambient temperature trend to determine whether it can enter Quiet

operation (low compressor speed and low O.D. fan speed).

SW5 SW7SW6

SW5 DIP Switch Settings

*Factory Default Setting

WJ26X25053 - Outdoor Power Control Board DIP Switch Settings

OUTDOOR TECHNICAL OVERVIEW

B-23

ENGLISH

Topic TitleDIP Switch Settings

WJ26X25054 - Service Monitor Board DIP Switch Settings

Outdoor Central

Control Address

SW6-1 SW6-2 SW6-3 SW6-4

0 OFF OFF OFF OFF

1 OFF OFF OFF ON

2 OFF OFF ON OFF

3 OFF OFF ON ON

4 OFF ON OFF OFF

5 OFF ON OFF ON

6 OFF ON ON OFF

7 OFF ON ON ON

8 ON OFF OFF OFF

9 ON OFF OFF ON

10 ON OFF ON OFF

11 ON OFF ON ON

12 ON ON OFF OFF

13 ON ON OFF ON

14 ON ON ON OFF

15 ON ON ON ON

Outdoor central control address settings

Definition SW1-1 SW1-2 SW1-3 SW1-4

Factory default OFF OFF OFF OFF

Forced heating ON OFF OFF OFF

Forced cooling OFF ON OFF OFF

Rated operation OFF OFF ON OFF

Time defrost valid: Defrost initiates if

needed when the compressor has been on

for 10 minutes continuously and 50 minutes

cumulative. Termination conditions are the

same as demand defrost.

OFF OFF OFF ON

Wiring check active* ON ON ON ON

Description SW7-1 SW7-2 SW7-3 SW7-4 SW7-5 SW7-6 SW7-7 SW7-8

USA energy efficiency test mode for High Wall unit OFF* OFF* ---- ---- ---- ---- ---- ----

USA energy efficiency test mode for Duct unit ON OFF ---- ---- ---- ---- ---- ----

Reserved ---- OFF* ---- ---- ---- ---- ----

Reserved ---- ---- ---- OFF* ---- ---- ---- ----

Reserved ---- ---- ---- ---- OFF* ---- ---- ----

Reserved ---- ---- ---- ---- ---- OFF* ---- ----

North American region ---- ---- ---- ---- ---- ---- ON* ----

Non-North American region ---- ---- ---- ---- ---- ---- OFF ----

Quiet operation valid ---- ---- ---- ---- ---- ---- ---- OFF*

SW6 DIP Switch Settings

SW1 DIP Switch Settings

SW7 DIP Switch Settings

*Factory Default Setting

*See page B-18 for Wiring Error Check.

OUTDOOR TECHNICAL OVERVIEW

B-24

ENGLISH

Topic TitleError Codes

LED Error

Code

Diagnosis

1 Outdoor EEPROM failure

2 IPM overcurrent or short circuit

4 Communication failure between the IPM and outdoor PCB

5 Module operated overload (compressor overload protection)

6 Module low or high voltage

8 Overheat protection for discharge temperature

9 Malfunction of the DC fan motor

10 Malfunction of defrost temperature sensor

11 Suction temperature sensor failure

12 Ambient temperature sensor failure

13 Discharge temperature sensor failure

15 Communication failure between the indoor & outdoor unit

16 Lack of refrigerant or discharging

17 4-way valve switching failure

18 Loss of synchronism detection

20 Indoor thermal overload

21 Indoor unit overload protection, heating mode only.

21 Indoor coil frosted

23 Module thermal overload

24 Compressor start failure, over-current

25 Phase current protection (IPM)

26 MCU reset

27 Module current detect circuit malfunction

28 Liquid pipe sensor failure: Circuit A

29 Liquid pipe sensor failure: Circuit B

30 Liquid pipe sensor failure: Circuit C

31 Liquid pipe sensor failure: Circuit D

32 Gas pipe sensor failure: Circuit A

33 Gas pipe sensor failure: Circuit B

34 Gas pipe sensor failure: Circuit C

35 Gas pipe sensor failure: Circuit D

36 Gas pipe sensor failure: Circuit E

Malfunction of module temperature sensor momentary power failure

detection

39 Malfunction of condensing temperature sensor

40 Liquid pipe sensor failure: Circuit E

41 Toci temperature sensor failure

42 High Pressure switch open

43 Low Pressure switch open

System high pressure protection: Overcharged, high condensing

temperature or malfunction of fan motor.

System low pressure protection: Undercharged, low defrosting

temperature, or malfunction of fan motor.

L0 OAT less than -22°F (-30°C)

Precautions For Adding Refrigerant

1. This system must use refrigerant R410A.

2. Add refrigerant 0.20 oz/ft per meter

when the total piping length exceeds the

standard value.

3. The total liquid piping length must be less

than the max value.

Outdoor Unit Std. Value Max Value

2U20EH2VHA 30m/100ft. 50m/164ft.

3U24EH2VHA 30m/100ft. 60m/197ft.

4U36EH2VHA 40m/131ft. 70m/230ft.

Notes:

1. No addressing is necessary. All indoor wiring

connections must match the outdoor connections, or

a communication failure will result.

2. Set SW5-8 to ON for Quiet Operation if desired.

Maximum capacity may be slightly reduced.

3. Do not change any switch settings unless directed to

do so.

* PCB: Printed Circuit Board

* IPM: Inverter Power Module

* EEV: Electronic Expansion Valve

WALL MOUNT TECHNICAL OVERVIEW

C-1

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WALL MOUNT TECHNICAL OVERVIEW

Table of Contents

Components ......................................................................................................................................................................... C- 2

Component Overview ......................................................................................................................................................... C- 2

Indoor Wall Mount Unit Circuit Board ................................................................................................................................. C-3

Testing .................................................................................................................................................................................. C- 5

Accessing Components/Removing Cover......................................................................................................................... C-5

Indoor Fan Motor Voltage Check ........................................................................................................................................ C- 6

Replacing the Blower Motor ................................................................................................................................................ C-6

Testing Temperature Sensors ............................................................................................................................................. C-8

Testing Louver Motors ........................................................................................................................................................ C-8

Testing Communication Circuit .......................................................................................................................................... C-8

Wiring Diagram ..................................................................................................................................................................... C- 9

Error Codes ......................................................................................................................................................................... C-10

AW07EH2VHA

AW09EH2VHA

AW12EH2VHA

AW18EH2VHA

AW07LC2VHB

AW09LC2VHB

AW12LC2VHB

AW18LC2VHB

AW24LP2VHA

WALL MOUNT TECHNICAL OVERVIEW

C-2

ENGLISH

Components

Terminal Block

Power to operate the indoor unit comes from the

electrical line voltage terminal block at the outdoor unit.

The wiring includes 4 wires: 1, 2, 3 and ground. Wires 1

and 3 complete the data path. These wires should always

be 14 gauge AWG Stranded type wire. Splices in wires 1

or 3 may cause communication errors.

Blower Assembly

The blower assembly consists of a plastic blower wheel

that is connected to a variable speed indoor blower

motor. A set screw holds the blower wheel to the blower

motor.

The indoor blower motor is a DC Fan Motor that is

connected to the indoor unit control board. The wiring

from the motor to indoor board consists of 5 wires

connected to pins 1, 4, 5, 6 and 7. Pin 1 should have 310

VDC. Pin 4 is ground. Pin 5 +15VDC. Pin 6 is the feedback

signal. Pin 7 is the speed control.

During normal operation, the indoor control board will

energize the indoor blower motor and request proper

speed. The indoor blower motor will control the speed

via a command at the Pin 7 speed control. Proper fan

speed is veried by the indoor control board via the

voltage level at the feedback signal on Pin 6. Should

the feedback signal not be present during a call for

indoor blower, the indoor control board will indicate a

Malfunction Code E14.

Louver Stepper Motors

Separate motors located in the indoor unit control the

operation of the motorized louvers. All of the louver

motors are controlled via commands received from the

remote control. The blower motor is controlled by both

the remote control and by commands from the outdoor

unit ECU.

Pipe Temperature Sensor

The Piping Temperature Sensor senses indoor coil

temperature in the cooling mode and in the heating

mode. This sensor is used for Anti Freezing and Anti

Cold Blow cycles. The sensor also provides critical

temperature information to the ECU that may be used in

frequency adjustments.

Ambient Temperature Sensor

The ambient air sensor senses the temperature of

the air being drawn into the wall mounted unit from

the conditioned space. This sensor provides room

temperature information to the ECU for calculation of

inverter capacity and temperature control.

The wall mounted units act as evaporator coils during cooling mode and condenser coils during heating mode. These units have

gravity condensate drain systems. If a condensate pump is needed, it must be eld provided and mounted external to the indoor

unit.

The wall mount unit is shipped

with a wireless controller.

Component Overview

WALL MOUNT TECHNICAL OVERVIEW

C-3

ENGLISH

Up/Down Stepper

Motor

Left Stepper Motor

Display Board

Emergency Switch

Wired Controller

Temperature Sensors

15A/250VAC Fuse

DC Fan Motor

LED

DIP Switch Bank SW2

WiFi

Components

Display

The indoor unit has a display that communicates system mode, room temperature and diagnostic code information. The

diagnostic code information shown on the indoor unit will NOT be the same code that is displayed on the outdoor unit.

When servicing a diagnostic error, compare the indoor unit code to the outdoor unit code to make diagnostic decisions.

Codes that relate to outdoor unit problems should use the outdoor unit display information as priority.

Control Board

The indoor unit circuit board controls the switching functions of the indoor unit. All control decisions are made by the

outdoor unit ECU. The indoor board has some limited diagnostic capability which will be covered in this manual.

Evaporator Coil

Indoor Wall Mount Unit Circuit Board

The Indoor Unit Circuit Board communicates with the outdoor

unit ECU via a connection at Terminal Block screw 3.

The data pulse that sends the communication information

can be measured with a voltmeter placed to DCV range. From

the ground connection at the Terminal Block to the Number 3

screw connection, the voltage should pulse up and down when

data is being transmitted.

This control board has control over the fan louver movement,

manual fan blower control, indoor coil temperature and indoor

air temperature sensing functions. All operational decisions

are controlled by the OUTDOOR UNIT ECU. The connections

on the indoor board are shown here in the schematic drawing.

WALL MOUNT TECHNICAL OVERVIEW

C-4

ENGLISH

Topic TitleComponents

Emergency Run

Switch

Line voltage to power the indoor unit comes in on Terminal

Block connections 1 and 2. Power connects from these

terminal connections on the circuit board. If the board does

not respond to commands and has no display, check for line

voltage at these connections. When power is present at the

indoor board, the RED LED on the circuit board will blink a 2

ash code.

The control board has a replaceable 3.15A 250V fuse that

protects against excessive current. If power is present at

the board but the board does not work, check for continuity

through the fuse. Replace if the fuse is open.

The indoor unit temperature sensors are connected to the

control board. When testing the calibration of these sensors,

the wires can be released from the plug by pressing on the

tension tab on the side of the plug.

The receiver/display unit that is mounted to the front cover of

the indoor unit plugs into the control board.

There are two to three motors connected to the control board

that control the movement of the louvers right, left and up/

down. Some units will use one motor to operate the right and

left movement function.

The blower motor is connected to the circuit board.

There is an Emergency Run switch on the edge of the indoor

board that will put the system into Auto Mode should the

remote control break or be lost. When this switch is pressed

and held for 5 seconds, the indoor unit display will beep twice

and the system will enter TEST MODE.

WALL MOUNT TECHNICAL OVERVIEW

C-5

ENGLISH

Testing

6. Open the 3 caps that cover the screws located behind the

bottom of the louver. These caps ip up.

1. To access components for service, rst disconnect power

to the outdoor unit. This will de-energize the indoor unit.

2. Lift the front cover by prying on the two indented nger

holds at each end of the indoor unit.

3. Remove the three Phillips head screws located near the

bottom of the indoor unit. These screws are located

directly below the bottom of the air lter.

4. Remove the lters.

5. Manually open the louver.

7. Remove the three screws located behind the caps.

8. Remove the two screws that hold the digital display to the

front cover. The display can hang free.

9. Release the air temperature sensor from the clip that

holds it.

10. Pull upward on the top of the indoor unit cover to free

it from the four retaining clips. The cover will pivot

downward. The cover should now pull away from the

indoor unit.

Accessing Components/Removing Cover

WALL MOUNT TECHNICAL OVERVIEW

C-6

ENGLISH

Testing

If The Indoor Fan Motor Does Not Run:

1. Remove the front cover and access the circuit board fan motor

connection.

2. Reset power and turn the remote control fan command to Fan

On mode.

1. Disconnect the power.

2. With the indoor unit cover removed, remove the two

screws on the left plastic evaporator coil bracket.

Motor Test:

1. If the motor doesn’t run, check for 310VDC between Pins 1

and 3. If it is not present, the indoor board is bad. If voltage

is present, continue on.

2. Check the voltage between Pins 3 and 4. The voltage

should be +15VDC. If it is not present, the board is bad. If

voltage is present, continue on.

3. Check for voltage between Pins 3 and 6. If no DC voltage is

present, the board is bad. If voltage is present, change the

motor.

3. Remove the cover from the electrical box on the right side

of the indoor unit.

4. Remove the two screws that hold the electrical box in

place.

5. Lift and swing the electrical box out of the way.

Indoor Fan Motor Voltage Check

Replacing the Blower Motor

DC Motor

+310 VDC

DC Ground

+15 VDC

Signal

Feedback

Red

Black

White

Yellow

Blue

WALL MOUNT TECHNICAL OVERVIEW

C-7

ENGLISH

Testing

6. Remove 6 screws that hold the motor bracket and

evaporator coil.

7. Lift the evaporator coil and remove the motor bracket.

8. Loosen the motor shaft set screw. Phillips head screw.

9. Unplug the motor from the circuit board.

10. Lift and slide the motor away from the blower wheel.

11. Remove the two black anti vibration mounts from the

defective motor and place them on the new motor.

12. Install new motor in reverse order.

WALL MOUNT TECHNICAL OVERVIEW

C-8

ENGLISH

Testing

Testing Temperature Sensors

The easiest problems to solve will involve codes that are

related to potential failure of temperature sensors. Common

problems may include loose connections, open electrically,

and out of calibration. Checking the condition of the sensors

requires a temperature probe and an ohmmeter.

The Reference Section of this manual contains temperature

resistance tables that can be used to check the calibration

of the sensors. The measured resistance must be within the

tolerances printed on the top of the tables.

To test the electrical condition of a temperature sensor

perform the following:

1. Conrm the sensor is rmly attached to the circuit

board connection plug.

2. Remove the sensor wires from the connection plug by

releasing holding tension on the plugs tension tab.

3. Use an ohmmeter to test the electrical resistance of the

sensor.

4. Measure the air temperature near the sensor and compare

the required resistance against measured resistance.

(See chart in reference section) If the sensor is within

calibration, the sensor is good. If the sensor is out of

calibration, replace the sensor. (Tube Sensors should be

removed from socket and exposed to air temperature

during test.)

Testing Louver Motors

If the louver does

not operate with

command from the

remote control,

either the indoor

board is bad, or

the louver motor is

defective. It is more

likely the motor is

defective than the board. (Make sure the louver assembly is

not binding and keeping the vanes from moving.)

1. Remove power from the unit and remove the indoor unit

cover.

2. Access the circuit board.

Testing Communication Circuit

If an Error E7 occurs, perform the following test to determine

if the indoor control board is functioning properly to send data

to the outdoor unit.

Perform this test with the unit powered and all wiring

connected between indoor and outdoor unit.

Make sure all wiring between the indoor and outdoor unit

are correct. There should no splices between the indoor and

outdoor unit wiring connecting terminals 1 or 3. Make sure

wiring is correct, before performing this test.

1. Measure the DC voltage between terminals 1 and 3 on the

indoor terminal block.

2. C and 23VDC. The uctuating signal indicates a good

communication path.

3. If the voltage does not uctuate, and the wiring is good,

the indoor board is defective.

3. Identify on the schematic drawing the inoperable louver

motor and disconnect the plug from the circuit board. (The

up down louver motor is located on the right side of the

indoor unit. The left right louver motor is located bottom

center. )

4. Use an Ohmmeter to test the electrical continuity of the

louver motor windings. The proper resistance for each

winding can be found in this table. If the motor winding

resistance is erratic or shows open, the motor is defective.

Replace the motor.

5. If the motor checks out good, replace the indoor control

board.

WALL MOUNT TECHNICAL OVERVIEW

C-9

ENGLISH

Topic Title Wiring Diagrams

WALL MOUNT TECHNICAL OVERVIEW

C-10

ENGLISH

Error Codes

The error codes that are displayed on the indoor units may vary from the outdoor unit codes. The information communicated by

the error code will be the SAME for both indoor and outdoor units even though the numbers may dier.

Indoor

Display

Outdoor

LED

Diagnosis

F12 1 Outdoor EEPROM failure

F1 2 IPM overcurrent or short circuit

F22 / Outdoor alternating current, over current protection

F3 4 Communication failure between the IPM and outdoor PCB

F20* 5 Module operated overload (compressor overload protection)

F19* 6 Module low or high voltage

F27 / Compressor current sampling circuit fault

F4 8 Overheat protection for discharge temperature

F8* 9 Malfunction of the DC fan motor

F21 10 Malfunction of defrost temperature sensor

F7 11 Suction temperature sensor failure

F6 12 Ambient temperature sensor failure

F25 13 Discharge temperature sensor failure

F30* / High outdoor suction temperature

E7 15 Communication failure between the indoor & outdoor unit

F13* 16 Lack of refrigerant or discharging

F14* 17 4-way valve switching failure

F11 18 Loss of synchronism detection

F28 / Position detection circuit fault of compressor

F15* / Terminal block temp too high

E9 20 Indoor thermal overload

E9* 21 Indoor unit overload protection, heating mode only.

E5 21 Indoor coil frosted

E5* / Indoor anti-frosting protection

F5* 23 Module thermal overload

F2* 24 Compressor start failure, over-current

F23* 25 Phase current protection (IPM)

F9 26 MCU reset

F24 27 Module current detect circuit malfunction

F10 28 Liquid pipe sensor failure: Circuit A

F16 29 Liquid pipe sensor failure: Circuit B

F17 30 Liquid pipe sensor failure: Circuit C

F18 31 Liquid pipe sensor failure: Circuit D

F29 32 Gas pipe sensor failure: Circuit A

F30 33 Gas pipe sensor failure: Circuit B

F31 34 Gas pipe sensor failure: Circuit C

F32 35 Gas pipe sensor failure: Circuit D

F26 36 Gas pipe sensor failure: Circuit E

F34 / Outdoor pipe temperature protection in cooling mode

F35 38 Malfunction of module temperature sensor momentary power failure detection

F36 39 Malfunction of condensing temperature sensor

F33 40 Liquid pipe sensor failure: Circuit E

F38 41 Toci temperature sensor failure

F39 42 High Pressure switch open

F40 43 Low Pressure switch open

F41 44 System high pressure protection: Overcharged, high condensing temperature or malfunction of fan motor.

F42 45 System low pressure protection: Undercharged, low defrosting temperature, or malfunction of fan motor.

F43 / Incorrect match between indoor & outdoor

E1 / Indoor ambient temperature sensor failure

E2 / Indoor coil temperature sensor failure

E4 / Indoor PCB EEPROM failure

E14* / Indoor fan motor malfunction

* Hidden indoor error code. LED1 will ash outdoors, but no error will appear on indoor unit display. To view error code on indoor display, press and hold the

Emergency button for 15 seconds.

COMPACT CASSETTE TECHNICAL OVERVIEW

D-1

ENGLISH

COMPACT CASSETTE TECHNICAL OVERVIEW

Table of Contents

Components ......................................................................................................................................................................... D-2

Component Overview ......................................................................................................................................................... D-2

Cassette Unit Indoor Circuit Board .....................................................................................................................................D-4

Testing .................................................................................................................................................................................. D-5

Accessing the Blower Motor and Condensate Pump ........................................................................................................D-5

Removing Fan Motor ...........................................................................................................................................................D-5

Removing Condensate Pump .............................................................................................................................................D-5

Indoor Fan Motor Test Procedure .......................................................................................................................................D-6

Testing Temperature Sensors .............................................................................................................................................D-6

Testing Louver Motors ........................................................................................................................................................D-7

Testing Communication Circuit ..........................................................................................................................................D-7

Test Condensate Pump and Associated Float Switch .......................................................................................................D-8

Wiring Diagram & DIP Switch Settings ..................................................................................................................................D-9

Error Codes .........................................................................................................................................................................D-10

AB09SC2VHA

AB12SC2VHA

AB18SC2VHA

COMPACT CASSETTE TECHNICAL OVERVIEW

D-2

ENGLISH

Components

The indoor cassette type units act as evaporator coils during cooling mode and condenser coils during heating mode. These

units have a built in condensate pump with an associated condensate level switch. The condensate pump is capable of lifting

water out of the indoor unit. If high water lift is needed, the water from the cassette pump should be pumped into a eld supplied

condensate pump with high lift power.

Cassette type indoor units can be operated with a wired controller or a remote control.

Terminal Block

Power to operate the indoor unit comes from the electrical line voltage terminal block at the outdoor unit. The wiring

includes 4 wires, 1, 2, 3 and ground. Wires 1 and 3 complete the data path. These wires should always be 14 gauge AWG

Stranded type wire. Splices in wires 1 or 3 may cause communication errors.

Motor Blower

The indoor unit features a multi speed blower motor that will change speed to match the capacity demand from the

outdoor unit. Separate motors located in the indoor unit control the operation of the motorized louvers. All of the louver

motors are controlled via commands received from the remote control. The blower motor is controlled by both the remote

control and by commands from the outdoor unit ECU.

Display

The indoor unit has a display that communicates system mode. The indoor unit does not display temperatures or

diagnostic codes. When a wired controller is used, this information is displayed on the wired controller. It is recommended

to use a wired controller with the cassette unit.

When servicing a diagnostic error, ALWAYS refer to the outdoor unit code to make diagnostic decisions.

Component Overview

COMPACT CASSETTE TECHNICAL OVERVIEW

D-3

ENGLISH

Topic TitleComponents

The Blower Assembly

The blower assembly consists of a plastic blower wheel that is connected to a PSC indoor blower motor. A set screw holds

the blower wheel to the blower motor.

The indoor blower motor is a Multi Speed Fan Motor that is connected to the indoor unit control board. The wiring from the

motor to indoor board consists of 4 wires connected to pins common, low , medium and high speeds.

During normal operation, the indoor control board will energize the indoor blower motor and request proper speed. The

motor has a run capacitor that is located in the Cassette unit’s control box. The run capacitor connects to the motor via

two orange wires. This capacitor is eld replaceable.

Louver Motors

The louver motors are stepper type motors that move the louvers up/down. The motors are controlled by pulsed voltage

that cannot be measured. If the louver does not move when it should, check for a bind in the louvers.

Piping Temperature Sensor

The Piping Temperature Sensor senses indoor coil temperature in the cooling mode and in the heating mode. This sensor is

used for Anti Freezing and Anti Cold Blow cycles. The sensor also provides critical temperature information to the ECU that

may be used in frequency adjustments.

Ambient Temperature Sensor

The Ambient Temperature Sensor senses room temperature. This sensor provides room temperature information to the

ECU for calculation of inverter capacity and temperature control.

Both sensors are negative temperature coecient type that reduce electrical resistance as temperature rises.

Control Board

The indoor unit circuit board controls the switching functions of the indoor unit. All control decisions are made by the

outdoor unit ECU. The indoor board has some limited diagnostic capability which will be covered in this manual.

Condensate Pump & Float Switch

COMPACT CASSETTE TECHNICAL OVERVIEW

D-4

ENGLISH

Topic TitleComponents

The indoor unit circuit board controls the switching functions

of the indoor unit. All control decisions are made by the

outdoor unit ECU. The indoor board has some limited

diagnostic capability which will be covered in this manual.

The Indoor Unit Circuit Board communicates with the outdoor

unit ECU via a connection at Terminal Block screw 3. The

data pulse that sends the communication information can be

measured with a voltmeter placed to DCV range. From the

ground connection at the Terminal Block to the Number 3

screw connection, the voltage should pulse up and down when

data is being transmitted.

This control board has control over the fan louver movement,

manual fan blower control, indoor coil temperature and indoor

air temperature sensing functions. All operational decisions

are controlled by the OUTDOOR UNIT ECU.

The connections on the indoor board are shown here in the

schematic drawing.

Line voltage to power the indoor unit comes in on Terminal

Block connections 1 and 2. Power connects from these

terminal connections to CH- 3 and CH-4 on the circuit board.

If the board does not respond to commands and has no

display, check for line voltage at these connections. When

power is present at the indoor board, the Display Power

Indicator will be lit.

The control board has a replaceable 3.15A 250V fuse that

protects against excessive current. If power is present at

the board but the board does not work, check for continuity

through the fuse. Replace if the fuse is open.

The indoor unit temperature sensors are connected at

Plug CN-13. When testing the calibration of these sensors,

the wires can be released from the plug by pressing on the

tension tab on the side of the plug.

The receiver/display unit that is mounted to the front

cover of the indoor unit plugs into the circuit board via a

connection at Plug CN-29.

There is one motor that controls the movement of the

louvers. The motor connects to the circuit board at Plug CN-

14. The motor is located in the over of the louver assembly.

The blower/fan motor is connected to the circuit board at

plug CN-11.

The Cassette unit has a built in condensate pump. The pump

is connected to the circuit board on Plug CN-9. The pump

is energized whenever the Float Switch indicates that water

needs to be pumped from the cassette. The oat switch

connects onto the circuit board via Plug CN-18.

N Terminal

L Terminal

Communication Terminal

3.15A 250V Fuse

CN3 Pipe/Room Temp Sensors

CN19 Float Switch

CN21 Louver Panel

CN11 Wired Remote

DIP Switches

CN35 Stepper Motor

CN6 Fan Motor

CN9 Condensate Pump

CN4 U-HOME

CN13 Remote Central

CN1 Room Card

Cassette Unit Indoor Circuit Board

COMPACT CASSETTE TECHNICAL OVERVIEW

D-5

ENGLISH

Testing

Accessing the Blower Motor and Condensate Pump

1. Disconnect power to the outdoor unit.

2. Remove the louver assembly.

Removing Fan Motor

1. Remove holding nut from fan blade.

Removing Condensate Pump

1. Remove screws holding condensate pump and oat switch

in position.

2. Disconnect condensate hose from condensate pump.

3. Remove assembly.

8. Slide condensate pan from cassette.

2. Fan blade will slide o motor shaft.

3. Remove Phillips head screw holding cover plate over motor

wiring leads.

4. Remove 3 nuts that hold fan motor in place.

5. Fan motor will come loose.

3. Disconnect the main power wire to the indoor unit.

4. Unplug the condensate pump and oat switch from wiring

harness.

5. Unplug fan motor from wiring harness.

6. Remove ground wire from ground screw on electrical

box. Remove electrical box.

7. Remove 5 screws holding foam condensate pan bottom in

place.

COMPACT CASSETTE TECHNICAL OVERVIEW

D-6

ENGLISH

Testing

Indoor Fan Motor Test Procedure

If the indoor fan motor does not run:

1. Disconnect power to the system.

2. Remove the return air cover and access the circuit board connection.

3. Reset power and turn the remote control fan command to Fan On mode.

Testing Temperature Sensors

The easiest problems to solve will involve codes that are related to potential failure of temperature sensors. Common problems

may include loose connections, open electrically, and out of calibration. Checking the condition of the sensors requires a

temperature probe and an ohmmeter.

The Reference Section of this manual contains temperature resistance tables that can be used to check the calibration of the

sensors. The measured resistance must be within the tolerances printed on the top of the tables.

To test the electrical condition of a temperature sensor perform the following:

1. Conrm the sensor is rmly attached to the circuit board connection plug.

2. Remove the sensor wires form the connection plug by releasing holding tension on the plugs tension tab.

3. Use an ohmmeter to test the electrical resistance of the sensor.

4. Measure the air temperature near the sensor and compare the required resistance against measured resistance. (See chart in

reference section) If the sensor is within calibration, the sensor is good. If the sensor is out of calibration, replace the sensor.

(Tube Sensors should be removed from socket and exposed to air temperature during test.)

Motor Test:

1. If the motor doesn’t run, check for 310VDC between Pins 1

and 3. If it is not present, the indoor board is bad. If voltage

is present, continue on.

2. Check the voltage between Pins 3 and 4. The voltage

should be +15VDC. If it is not present, the board is bad. If

voltage is present, continue on.

3. Check for voltage between Pins 3 and 6. If no DC voltage

is present, the board is bad. If voltage is present, change

the motor.

2 4

DC Motor

+310 VDC

DC Ground

+15 VDC

Signal

Feedback

Red

Black

White

Yellow

Blue

COMPACT CASSETTE TECHNICAL OVERVIEW

D-7

ENGLISH

TO OUT DOOR

0150515406

BM1-1

BM1-7

BM1-8

TYPE DEFINE

OFFOFF

BM1-2 BM1-3

BTU

B:BLACK

R:RED

W:WHITE

Y/G:YELLOW/GREEN

TEMP.

SENSOR

ROOM

SENSOR

FLOAT

SWITCH

HEATER

PUMP

UP/DOWN

CN9

CN1

CN6

PANNEL

CN4

CN11

CN19

CN13

CN3

CN35

CN21

T5A/250VAC

FUSE

BM3

Y/G

OFF OFF OFF

ON OFF OFF

OFF ON OFF

ON ON OFF

OFF OFF ON

ON OFF ON

OFF ON ON

ON ON ON

9000

12000

18000

24000

28000

36000

48000

60000

NOTE1.DASHED PART ARE OPTIONAL.

USER SHOULD NOT TO SET BM1 AND BM3

CH1

OFF OFF

BM1-4

BM1-5

BM1-6

OFF

CN16

CN8

TEMP.

PIPING

DC FAN

ROOMCARD

U-HOME

WIRED

CONTROLLER

REMOTE

CENTRAL

87654321

BM1

OFF

87654321

OFF

Room card

available

unavailable

AB09SC2VHA/AB09CS2ERA

AB12SC2VHA/AB12CS2ERA(S)

AB18SC2VHA/AB18CS2ERA(S)

Default

Testing

Testing Louver Motors

If the louver does not operate with command from the remote

control, either the indoor board is bad, or the louver motor

is defective. It is more likely the motor is defective than the

board. (Make sure the louver assembly is not binding and

keeping the vanes from moving.)

1. Remove power from the unit and remove the indoor unit

cover.

2. Access the circuit board.

3. Identify the inoperable louver motor on the schematic

drawing below and disconnect the plug from the circuit

board.

4. Use an Ohmmeter to test the electrical continuity of the

louver motor windings. The proper resistance for each

winding can be found in this table. If the motor winding

resistance is erratic or shows open, the motor is defective.

Replace the motor.

5. If the motor checks out good, replace the indoor control

board.

Testing Communication Circuit

If an Error E7 occurs, perform the following test to determine

if the indoor control board is functioning properly to send data

to the outdoor unit.

Perform this test with the unit powered and all wiring

connected between indoor and outdoor unit.

Make sure all wiring between the indoor and outdoor unit

are correct. There should no splices between the indoor and

outdoor unit wiring connecting terminals 1 or 3. Make sure

wiring is correct, before performing this test.

1. Measure the DC voltage between terminals 1 and 3 on the

indoor terminal block.

2. The voltage should uctuate between 8VDC and 23VDC.

The uctuating signal indicates a good communication

path.

3. If the voltage does not uctuate, and the wiring is good,

the indoor board is defective.

COMPACT CASSETTE TECHNICAL OVERVIEW

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Testing

Test Condensate Pump and Associated Float Switch

If the internal condensate pump does not operate, the pump may be bad or the oat switch may be defective. Perform the

following test:

1. Access the electrical control box.

2. Unplug the oat switch from the circuit board.

3. The pump should start.

4. If the pump does not start, check for voltage at the pump connector on the board. There should be 230 Volts AC to the pump.

If there is not, the circuit board is defective. If there is proper voltage to the pump, either the pump or associated pump wiring

is defective.

2 4

COMPACT CASSETTE TECHNICAL OVERVIEW

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ENGLISH

Wiring Diagram & DIP Switch Settings

BM1-1 BM1-2 BM1-3 BM1-4 BM1-5 BM1-6 BM1-7 BM1-8 Description

OFF OFF OFF -- -- -- -- -- Unit capacity: 9000

ON OFF OFF -- -- -- -- -- Unit capacity: 12000

OFF ON OFF -- -- -- -- -- Unit capacity: 18000

-- -- -- OFF -- -- -- -- Room card invalid(default)

-- -- -- ON -- -- -- -- Room card valid

-- -- -- -- OFF -- -- -- Heat pump( defult)

-- -- -- -- ON -- -- -- Cooling only

-- -- -- -- OFF OFF OFF Cassette(American)

Dip switch setting for Cassette :0151800208A

BM3 the dip switch setting is reserved

Cassette Unit DIP Switch Settings

TO OUT DOOR

0150515406

BM1-1

BM1-7

BM1-8

TYPE DEFINE

OFFOFF

BM1-2 BM1-3

BTU

B:BLACK

R:RED

W:WHITE

Y/G:YELLOW/GREEN

TEMP.

SENSOR

ROOM

SENSOR

FLOAT

SWITCH

HEATER

PUMP

UP/DOWN

CN9

CN1

CN6

PANNEL

CN4

CN11

CN19

CN13

CN3

CN35

CN21

T5A/250VAC

FUSE

BM3

Y/G

OFF OFF OFF

ON OFF OFF

OFF ON OFF

ON ON OFF

OFF OFF ON

ON OFF ON

OFF ON ON

ON ON ON

9000

12000

18000

24000

28000

36000

48000

60000

NOTE1.DASHED PART ARE OPTIONAL.

USER SHOULD NOT TO SET BM1 AND BM3

CH1

OFF OFF

BM1-4

BM1-5

BM1-6

OFF

CN16

CN8

TEMP.

PIPING

DC FAN

ROOMCARD

U-HOME

WIRED

CONTROLLER

REMOTE

CENTRAL

87654321

BM1

OFF

87654321

OFF

Room card

available

unavailable

AB09SC2VHA/AB09CS2ERA

AB12SC2VHA/AB12CS2ERA(S)

AB18SC2VHA/AB18CS2ERA(S)

Default

COMPACT CASSETTE TECHNICAL OVERVIEW

D-10

ENGLISH

Error Codes

The error codes that are displayed on the indoor units may vary from the outdoor unit codes. The information communicated by

the error code will be the SAME for both indoor and outdoor units even though the numbers may dier.

Indoor

LED5

Indoor

LED1

Outdoor

LED

Diagnosis

2 1 1 Outdoor EEPROM failure

2 2 2 IPM overcurrent or short circuit

2 3 / Outdoor alternating current, over current protection

2 4 4 Communication failure between the IPM and outdoor PCB

2 5 5 Module operated overload (compressor overload protection)

2 6 6 Module low or high voltage

2 7 / Compressor current sampling circuit fault

2 8 8 Overheat protection for discharge temperature

2 9 9 Malfunction of the DC fan motor

3 0 10 Malfunction of defrost temperature sensor

3 1 11 Suction temperature sensor failure

3 2 12 Ambient temperature sensor failure

3 3 13 Discharge temperature sensor failure

3 4 / High outdoor suction temperature

3 5 15 Communication failure between the indoor & outdoor unit

3 6 16 Lack of refrigerant or discharging

3 7 17 4-way valve switching failure

3 8 18 Loss of synchronism detection

3 9 / Position detection circuit fault of compressor

4 0 / Terminal block temp too high

4 0 20 Indoor thermal overload

4 1 21 Indoor unit overload protection, heating mode only.

4 1 21 Indoor coil frosted

4 2 / Indoor anti-frosting protection

4 3 23 Module thermal overload

4 4 24 Compressor start failure, over-current

4 5 25 Phase current protection (IPM)

4 6 26 MCU reset

4 7 27 Module current detect circuit malfunction

4 8 28 Liquid pipe sensor failure: Circuit A

4 9 29 Liquid pipe sensor failure: Circuit B

5 0 30 Liquid pipe sensor failure: Circuit C

5 1 31 Liquid pipe sensor failure: Circuit D

5 2 32 Gas pipe sensor failure: Circuit A

5 3 33 Gas pipe sensor failure: Circuit B

5 4 34 Gas pipe sensor failure: Circuit C

5 5 35 Gas pipe sensor failure: Circuit D

5 6 36 Gas pipe sensor failure: Circuit E

5 7 / Outdoor pipe temperature protection in cooling mode

5 8 38 Malfunction of module temperature sensor momentary power failure detection

5 9 39 Malfunction of condensing temperature sensor

6 0 40 Liquid pipe sensor failure: Circuit E

6 1 41 Toci temperature sensor failure

6 2 42 High Pressure switch open

6 3 43 Low Pressure switch open

6 4 44 System high pressure protection: Overcharged, high condensing temperature or malfunction of fan motor

6 5 45 System low pressure protection: Undercharged, low defrosting temperature, or malfunction of fan motor

6 6 / Incorrect match between indoor & outdoor

0 1 / Indoor ambient temperature sensor failure

0 2 / Indoor coil temperature sensor failure

0 4 / Indoor PCB EEPROM failure

0 7 / Communication fault between the indoor and outdoor unit

0 8 / Communication fault between the controller and Indoor unit

0 12 / Drain system malfunction

0 13 / Zero cross signal detected wrong

0 14 / Indoor fan motor malfunction

LARGE CASSETTE TECHNICAL OVERVIEW

E-1

ENGLISH

LARGE CASSETTE TECHNICAL OVERVIEW

Table of Contents

Components ..........................................................................................................................................................................E-2

Component Overview ..........................................................................................................................................................E-2

Cassette Unit Indoor Circuit Board ......................................................................................................................................E-4

Testing ...................................................................................................................................................................................E- 5

Accessing the Blower Motor and Condensate Pump .........................................................................................................E-5

Removing Fan Motor ............................................................................................................................................................E-5

Removing Condensate Pump ..............................................................................................................................................E-5

Indoor Fan Motor Test Procedure ........................................................................................................................................E- 6

Testing Temperature Sensors ..............................................................................................................................................E-6

Testing Louver Motors .........................................................................................................................................................E-7

Testing Communication Circuit ...........................................................................................................................................E- 7

Test Condensate Pump and Float Switch ............................................................................................................................ E-8

Wiring Diagram ......................................................................................................................................................................E- 9

DIP Switch Settings .............................................................................................................................................................E-10

Error Codes ..........................................................................................................................................................................E-11

AL24LP2VHA

LARGE CASSETTE TECHNICAL OVERVIEW

E-2

ENGLISH

Components

The indoor cassette type units act as evaporator coils during cooling mode and condenser coils during heating mode. These

units have a built in condensate pump with an associated condensate level switch. The condensate pump is capable of lifting

water out of the indoor unit. If high water lift is needed, the water from the cassette pump should be pumped into a eld supplied

condensate pump with high lift power.

Cassette type indoor units can be operated with a wired controller or a remote control.

Component Overview

Terminal Block

Power to operate the indoor unit comes from the electrical line voltage terminal block at the outdoor unit. The wiring

includes 4 wires, 1, 2, 3 and ground. Wires 1 and 3 complete the data path. These wires should always be 14 gauge AWG

Stranded type wire. Splices in wires 1 or 3 may cause communication errors.

Motor Blower

The indoor unit features a multi speed blower motor that will change speed to match the capacity demand from the

outdoor unit. Separate motors located in the indoor unit control the operation of the motorized louvers. All of the louver

motors are controlled via commands received from the remote control. The blower motor is controlled by both the remote

control and by commands from the outdoor unit ECU.

Display

The indoor unit has a display that communicates system mode. The indoor unit does not display temperatures or

diagnostic codes. When a wired controller is used, this information is displayed on the wired controller. It is recommended

to use a wired controller with the cassette unit.

When servicing a diagnostic error, ALWAYS refer to the outdoor unit code to make diagnostic decisions.

LARGE CASSETTE TECHNICAL OVERVIEW

E-3

ENGLISH

Components

The Blower Assembly

The blower assembly consists of a plastic blower wheel that is connected to a PSC indoor blower motor. A set screw holds

the blower wheel to the blower motor.

The indoor blower motor is a Multi Speed Fan Motor that is connected to the indoor unit control board. The wiring from the

motor to indoor board consists of 4 wires connected to pins common, low , medium and high speeds.

During normal operation, the indoor control board will energize the indoor blower motor and request proper speed. The

motor has a run capacitor that is located in the Cassette unit’s control box. The run capacitor connects to the motor via

two orange wires. This capacitor is eld replaceable.

Louver Motors

The louver motors are stepper type motors that move the louvers up/down. The motors are controlled by pulsed voltage

that cannot be measured. If the louver does not move when it should, check for a bind in the louvers.

Piping Temperature Sensor

The Piping Temperature Sensor senses indoor coil temperature in the cooling mode and in the heating mode. This sensor is

used for Anti Freezing and Anti Cold Blow cycles. The sensor also provides critical temperature information to the ECU that

may be used in frequency adjustments.

Ambient Temperature Sensor

The Ambient Temperature Sensor senses room temperature. This sensor provides room temperature information to the

ECU for calculation of inverter capacity and temperature control.

Both sensors are negative temperature coecient type that reduce electrical resistance as temperature rises.

Control Board

The indoor unit circuit board controls the switching functions of the indoor unit. All control decisions are made by the

outdoor unit ECU. The indoor board has some limited diagnostic capability which will be covered in this manual.

Condensate Pump & Float Switch

LARGE CASSETTE TECHNICAL OVERVIEW

E-4

ENGLISH

Components

Power

Communication Terminal

3.15A 250V Fuse

CN3 Pipe/Room Temp Sensors

CN19 Float Switch

CN11 Wired Remote

DIP Switches

CN36 Stepper Motor

CN6 Fan Motor

CN9 Condensate Pump

CN14 Panel Connection

Cassette Unit Indoor Circuit Board

The indoor unit circuit board controls the switching functions of

the indoor unit. All control decisions are made by the outdoor

unit ECU. The indoor board has some limited diagnostic

capability which will be covered in this manual.

The Indoor Unit Circuit Board communicates with the outdoor

unit ECU via a connection at Terminal Block screw 3. The

data pulse that sends the communication information can be

measured with a voltmeter placed to DCV range. From the

ground connection at the Terminal Block to the Number 3 screw

connection, the voltage should pulse up and down when data is

being transmitted.

This control board has control over the fan louver movement,

manual fan blower control, indoor coil temperature and indoor

air temperature sensing functions. All operational decisions are

controlled by the OUTDOOR UNIT ECU.

The connections on the indoor board are shown here in the

schematic drawing.

Line voltage to power the indoor unit comes in on Terminal

Block connections 1 and 2. Power connects from these terminal

connections to CH- 3 and CH-4 on the circuit board. If the

board does not respond to commands and has no display, check

for line voltage at these connections. When power is present at

the indoor board, the Display Power Indicator will be lit.

The control board has a replaceable 3.15A 250V fuse that

protects against excessive current. If power is present at

the board but the board does not work, check for continuity

through the fuse. Replace if the fuse is open.

The indoor unit temperature sensors are connected at

Plug CN-13. When testing the calibration of these sensors,

the wires can be released from the plug by pressing on the

tension tab on the side of the plug.

The receiver/display unit that is mounted to the front cover

of the indoor unit plugs into the circuit board via a connection

at Plug CN-29.

There is one motor that controls the movement of the

louvers. The motor connects to the circuit board at Plug CN-

14. The motor is located in the over of the louver assembly.

The blower/fan motor is connected to the circuit board at

plug CN-11.

The Cassette unit has a built in condensate pump. The pump

is connected to the circuit board on Plug CN-9. The pump is

energized whenever the Float Switch indicates that water

needs to be pumped from the cassette. The oat switch

connects onto the circuit board via Plug CN-18.

LARGE CASSETTE TECHNICAL OVERVIEW

E-5

ENGLISH

Testing

Accessing the Blower Motor and Condensate Pump

1. Disconnect power to the outdoor unit.

2. Remove the louver assembly.

Removing Fan Motor

1. Remove holding nut from fan blade.

Removing Condensate Pump

1. Remove screws holding condensate pump and oat switch

in position.

2. Disconnect condensate hose from condensate pump.

3. Remove assembly.

8. Remove screws holding the air inlet cover.

9. Drain the condensate water from the pan by removing

drain plug.

10. Remove the screws holding on the condensate pan

2. Fan blade will slide o motor shaft.

3. Remove Phillips head screw holding cover plate over motor

wiring leads.

4. Remove 3 nuts that hold fan motor in place.

5. Fan motor will come loose.

3. Disconnect the main power wire to the indoor unit.

4. Unplug the condensate pump and oat switch from wiring

harness.

5. Unplug fan motor from wiring harness.

6. Remove the oat switch, piping temperature sensor, fan

motor, and wired controller (if present) control board wire

connections . Disconnect plug to the coil sensor.

7. Remove screws holding the control box.

LARGE CASSETTE TECHNICAL OVERVIEW

E-6

ENGLISH

Testing

Indoor Fan Motor Test Procedure

If the indoor fan motor does not run:

1. Disconnect power to the system.

2. Remove the return air cover and access the circuit board fan motor connection.