Rinnai EX38DTN Direct Vent Wall Furnace User Manual

MODEL:

EX38DT

(RHFE-1006FTA)

RHF1006-1750(02)

Direct Vent Wall Furnace

Installation and Operation Manual

2 EX38DT Installation and Operation Manual



—Iftheinformaonintheseinstruconsisnotfollowedexactly,aﬁreorexplosion

mayresultcausingpropertydamage,personalinjuryordeath.

— Donotstoreorusegasolineorotherﬂammablevaporsandliquidsinthevicinityof

thisoranyotherappliance.

— WHATTODOIFYOUSMELLGAS

 Donottrytolightanyappliance.

 Donottouchanyelectricalswitch;donotuseanyphoneinyourbuilding.

 Immediatelycallyourgassupplierfromaneighbor’sphone.Followthegas

supplier’sinstrucons.

 Ifyoucannotreachyourgassupplier,calltheﬁredepartment.

— Installaonandservicemustbeperformedbyalicensedprofessional.

WARNING

Corporation used under license by Rinnai America Corporation. Rinnai America Corporation

continually updates materials, and as such, content is subject to change without notice.

This appliance may be installed in an aermarket, permanently located, manufactured

home (USA only) or mobile home, where not prohibited by local codes.

This appliance is only for use with the type of gas indicated on the rang plate. This

appliance is not converble for use with other gases, unless a cerﬁed kit is used.

EX38DT Installation and Operation Manual 3

Contents

1. Welcome ...................................................................................................................................... 4

1.1 To The Installer .................................................................................................................. 4

1.2 To The Consumer .............................................................................................................. 4

1.3 Acronyms and Abbreviations ............................................................................................. 4

2. Safety ........................................................................................................................................... 5

2.1 Safety Symbols .................................................................................................................. 5

2.2 Safety Precautions ............................................................................................................. 5

3. About the Direct Vent Furnace .................................................................................................. 7

3.1 Main Components ............................................................................................................. 7

3.2 Specifications .................................................................................................................... 8

3.3 Dimensions ....................................................................................................................... 9

4. Installation ................................................................................................................................. 10

4.1 Installation Guidelines ..................................................................................................... 10

4.2 What You Will Need ........................................................................................................ 11

4.3 Choose an Installation Location ..................................................................................... 12

4.4 Installation Steps ............................................................................................................ 16

4.5 Post-Installation Checklist ................................................................................................ 28

5. Operation ................................................................................................................................... 29

5.1 Safety Precautions .......................................................................................................... 29

5.2 Operating Instructions ..................................................................................................... 30

5.3 Control Panel .................................................................................................................. 31

5.4 Basic Operation Settings ................................................................................................ 31

5.5 Add Water to the Humidifier ............................................................................................ 36

5.6 Adjust Air Flow Direction ................................................................................................. 36

5.7 Restart Function ............................................................................................................. 36

5.8 Diagnostic Codes ............................................................................................................ 37

6. Maintenance .............................................................................................................................. 38

7. Troubleshooting ............................................................................................................

........... 39

8. Parts ........................................................................................................................................... 41

9. Appendices ............................................................................................................................... 51

9.1 Massachusetts State Gas Regulations ........................................................................... 51

9.2 Wiring Diagram ............................................................................................................... 52

9.3 Ladder Diagram .............................................................................................................. 53

10. Warranty .................................................................................................................................. 54

4 EX38DT Installation and Operation Manual

1. Welcome

Thank you for purchasing a Rinnai Direct

Vent Furnace. Before installing and operating

the direct vent furnace, be sure to read these

instructions completely and carefully to

familiarize yourself with the direct vent

furnace's features and functionality.

 You must read the entire manual to properly

operate the direct vent furnace.

 Refer to section "6. Maintenance" to stay up

to date on regular maintenance for your

direct vent furnace.

 As when using any appliance generating

heat, there are certain safety precautions

you should follow. See section “2. Safety”

for detailed safety precautions.

 Be sure your direct vent furnace is installed

by a trained and qualified professional.

 If installing in the state of Massachusetts,

you must read section “9.1 Massachusetts

State Gas Regulations” in this manual.

 Keep this manual for future reference.

 It is recommended that a trained and

qualified professional who has attended a

Rinnai training class complete the

installation. The warranty may be voided

due to any improper installation.

 A trained and qualified professional

should have skills such as:

 Gas sizing

 Connecting gas lines, valves, and

electricity

 Knowledge of applicable national,

state, and local codes

 Installing venting through a wall

 Training in installation of direct vent

furnaces. Training on Rinnai Direct

Vent Furnaces is accessible at

rinnaipro.myabsorb.com.

 Read all instructions in this manual before

installing the direct vent furnace. The

direct vent furnace must be installed

according to the exact instructions in this

manual.

 Proper installation is the responsibility of

the trained and qualified professional.

 When installation is complete, leave this

manual with the direct vent furnace or

give the manual directly to the consumer.

1.1 To The Installer

1.2 To The Consumer

ANSI

American National Standards

Institute

BTU British Thermal Unit

LPG Liquid Propane Gas

NG Natural Gas

NPT National Pipe Thread

OEM Original Equipment Manufacturer

PSI Pounds per Square Inch

VAC Volts Alternating Current

wc Inches of Water Column

Table 1 below lists common acronyms and

abbreviations used in this manual:

Table 1. Acronyms and Abbreviations

1.3 Acronyms and

Abbreviations

EX38DT Installation and Operation Manual 5

2. Safety

2.1 Safety Symbols

Indicates an imminently hazardous

situation which, if not avoided, will result in

personal injury or death.

Indicates a potentially hazardous situation

which, if not avoided, could result in personal

injury or death.

Indicates a potentially hazardous situation

which, if not avoided, could result in minor

or moderate injury. It may also be used to

alert against unsafe practices.

Safety alert symbol. Alerts you to

potential hazards that can kill or

hurt you and others.

This manual contains the following important

safety symbols. Always read and obey all

safety messages.

DANGER

CAUTION

WARNING

 Repairs should be performed by a

trained and qualified professional.

 Keep the area around the furnace

clear and free from combustible

materials, gasoline, and other

flammable vapors and liquids.

 Never store liquid propane containers

indoors.

 Do not use this furnace if any part has

been under water. Immediately call a

trained and qualified professional to

inspect the furnace and to replace any

part of the control system and any gas

control which has been under water.

 This furnace is equipped with a three-

prong plug for your protection against

shock hazard and should be plugged

directly into a properly grounded three-

prong receptacle. Do not cut or remove

the ground prong from this plug.

 Any alteration to the furnace or its

controls can be dangerous.

 Do not operate furnace with the panels

removed, cracked or broken.

Replacement of the panels should be

performed by a trained and qualified

professional.

WARNING

2.2 Safety Precautions

6 EX38DT Installation and Operation Manual

WARNING

When an existing Category I heater is removed or

replaced, the original venting system may no

longer be sized to properly vent the attached

appliances. Instructions shall also indicate effects

of an improperly sized venting system (formation of

condensate, leakage, spillage, etc.) and shall

specify the following test procedure.

WARNING: CARBON MONOXIDE POISONING

HAZARD

Failure to follow the steps outlined below for each

appliance connected to the venting system being

placed into operation could result in carbon

monoxide poisoning or death.

The following steps shall be followed for each

appliance connected to the venting system being

placed into operation, while all other appliances

connected to the venting system are not in

operation:

1. Seal any unused openings in the venting

system.

2. Inspect the venting system for proper size and

horizontal pitch, as required in the National

Fuel Gas Code, ANSI Z223.1/NFPA 54 or the

Natural Gas and Propane Installation Code,

CSA B149.1 and these instructions. Determine

that there is no blockage or restriction,

leakage, corrosion and other deficiencies

which could cause an unsafe condition.

3. As far as practical, close all building doors and

windows and all doors between the space in

which the appliance(s) connected to the

venting system are located and other spaces of

the building.

4. Close fireplace dampers.

5. Turn on clothes dryers and any appliance not

connected to the venting system. Turn on any

exhaust fans, such as range hoods and

bathroom exhausts, so they are operating at

maximum speed. Do not operate a summer

exhaust fan.

6. Follow the lighting instructions. Place the

appliance being inspected into operation.

Adjust the thermostat so appliance is operating

continuously.

7. Test for spillage from draft hood equipped

appliances at the draft hood relief opening after

5 minutes of main burner operation. Use the

flame of a match or candle.

8. If improper venting is observed during any of

the above tests, the venting system must be

corrected in accordance with the National Fuel

Gas Code, ANSI Z223.1/NFPA 54 and/or

Natural Gas and Propane Installation Code,

CSA B149.1.

9. After it has been determined that each

appliance connected to the venting system

properly vents when tested as outlined above,

return doors, windows, exhaust fans, fireplace

dampers and any other gas-fired burning

appliance to their previous conditions of use.

 Do not block the warm air discharge. Do not

allow anyone to sleep directly in front of the

furnace.

 Due to high temperatures, the furnace should

be located out of traffic and away from furniture

and draperies.

 Children and adults should be alerted to the

hazards of high surface temperature and

should stay away to avoid burns or clothing

ignition.

 Young children should be carefully supervised

when they are in the same room as the

furnace.

 Clothing or other flammable material should

not be placed on or near the furnace.

 Any safety screen or guard removed for

servicing must be replaced prior to operating

the furnace.

 Do not insert items into the louvers.

 Do not spray aerosols near the furnace while it

is operating. Most aerosols contain butane gas

which is flammable.

 Do not unplug the furnace while it is operating

or while the fans are on.

 Do not use bare hands to touch the front

louvers due to high temperatures which may

cause burns.

 Wear hand protection when touching the side

back covers, front louver, and rear intake for

the convection fan.

 Prevent dust from accumulating on the power

cord, side covers, and parts behind the

furnace.

 Do not sit on the furnace.

 Do not place containers of liquid on top of the

furnace. Water spillage can cause extensive

damage to the furnace and may result in

electric shock.

CAUTION

EX38DT Installation and Operation Manual 7

3. About the Direct Vent Furnace

3.1 Main Components

Topics in this section

 Main Components

 Specifications

 Dimensions

Front View

Back View

❶

Control Panel

❷

Warm Air Outlet

❸

Bottom Cover

❹

Humidifier (open panel to access)

❺

Rating plate (includes model number,

serial number, gas type, etc.). English

is on the right side; French is on the

left side.

❻

Air Filter

❼

Gas Connection (1/2 in./13 mm Male NPT)

❽

Combustion Air Intake Hose

❾

Plastic Tie for Air Inlet

❿

Room Temperature Sensor/Thermistor

⓫

Power Cord and Plug

⓬

Flue Manifold (Combustion/Exhaust)

⓭

Bent Elbow

⓮

Exhaust Pipe

⓯

Pipe Stopper

❹

❸

❶

❷

❾

Figure 2: Back View

Figure 1: Front View

❻

❼

❽

❿

⓫

⓬

⓭

⓯

⓮

❺

8 EX38DT Installation and Operation Manual

The efficiency rating of this furnace is a product thermal efficiency rating determined under continuous

operating conditions and was determined independently of any installed system.

Rinnai products are continually being updated and improved; therefore, specifications are subject to

change without prior notice.

EX38DT

Application

Approved for manufactured home (USA only) or mobile home or residential

installation convertible for use with natural gas and liquefied petroleum gases

(propane) when provision is made for the simple conversion from one gas to the

other. Approved for commercial setting. Approved for installation at altitudes up to

10,200 feet (3,109 m).

Natural Gas Liquid Propane Gas

Min. Supply Gas

Pressure

3.5 in. (89 mm) wc 8.0 in. (203 mm) wc

Max. Supply Gas

Pressure

10.5 in. (267 mm) wc 13.0 in. (330 mm) wc

Btu/h Input Low 13,200 High 38,400 Low 13,200 High 36,500

General

Description

Forced Combustion, Forced Convection, Flued Gas Furnace

Operation Push Button Electronic

Gas Connection 1/2 in. (13 mm) Male NPT

Gas Control Electronic

Burners Stainless Steel Bunsen Burner

Temperature

Control

Electronic Thermostat, Low, 60-80ºF (16-26°C) in 2ºF (1°C) Increments, High

Ignition System Electronic Spark Ignition

Flue System

The flue must be terminated to atmosphere with only flue components listed with the

furnace’s certification. Warranty will be voided if non-listed components are installed.

Humidifier Tray

Capacity - 6.3 pints (3,000 cc)

Electrical

Connections

AC 120 Volts, 60 Hz, 58 watts

Standby Power

0.7 watts

Weight

86 lbs (39 kg)

Sound Level

39-46 dB

Safety Features

 Overheat: The furnace will automatically shut down when exceeding a

predetermined temperature.

 Flame Failure: The furnace will automatically shut down if the burner flame is

extinguished.

 Power Failure: The furnace will shut off the gas if it loses electrical power.

 Power Surge Fuse: A glass fuse on the PC board protects against overcurrent. If

the fuse blows then all indicator lamps will be off.

 Spark Detector: The furnace automatically shuts down if there is an abnormal

spark at ignition.

 Fusible Link: In case the overheat feature does not prevent an overheat, then

the fusible link could break, shutting off the furnace.

3.2 Speciﬁcations

Table 2: Specifications

EX38DT Installation and Operation Manual 9

Measurements: inches (mm)

3.3 Dimensions

A full size wall template is provided on the furnace carton box. Do not discard until installation is complete.

IMPORTANT

Figure 3: Front View

Figure 4: Side View

Side View

Front View (Including Sample Wall Template Located on Furnace Carton Box)

Center of Furnace

Wall Bracket

Wall Opening

Position

Wall Opening Position

The hole center

should be within the

shaded area.

10 EX38DT Installation and Operation Manual

THIS SECTION IS INTENDED FOR THE

INSTALLER

Installer qualifications: A trained and qualified

professional must install the furnace, inspect it,

and leak test the direct vent furnace before use.

The warranty may be voided due to any improper

installation. The trained and qualified professional

should have skills such as: Gas sizing; Connecting

gas lines, valves, and electricity; Knowledge of

applicable national, state, and local codes;

Installing venting through a wall; and training in

installation of direct vent furnaces. Training for

Rinnai Direct Vent Furnaces is accessible online at

rinnaipro.myabsorb.com.

4. Installation

4.1 Installation

Guidelines

 This furnace discharges a large volume of warm air

next to the floor. Any particles in the air such as

cigarette smoke could cause discoloration in nylon

carpets containing dyes or vinyl surfaces.

 Rinnai suggests that a dedicated electrical circuit

with a 120V AC, 60 Hz, 10 amp power source be

used.

 A test plug is provided for testing of manifold

differential pressure. It is located on the modulating

gas valve.

 If you move to a different location, check the gas

type in your new area. The local gas authority will be

able to advise on local regulations.

 The installation must conform with local codes or, in

the absence of local codes, with the National Fuel

Gas Code, ANSI Z223.1/NFPA 54, or the Natural

Gas and Propane Installation Code, CSA B149.1.

 A manufactured home (USA only) or mobile home

OEM installation must conform with the

Manufactured Home Construction and Safety

Standard, Title 24 CFR, Part 3280, or, when such a

standard is not applicable, the standard for

Manufactured Home Installations, ANSI Z225.1, or

the standard for Gas Equipped Recreational Vehicles

and Mobile Housing, CSA Z240.4.

 The furnace, when installed, must be electrically

grounded in accordance with local codes or, in the

absence of local codes, with the National Electrical

Code, ANSI/NFPA 70, or the Canadian Electrical

Code, CSA C22.1.

 The furnace and its main gas valve must be

disconnected from the gas supply piping system

during any pressure testing of that system at test

pressures in excess of 1/2 psi (3.5 kPa).

 The furnace must be isolated from the gas supply

piping system by closing its equipment shutoff valve

during any pressure testing of the gas supply piping

system at test pressures equal to or less than 1/2 psi

(3.5 kPa).

 If the flooring is carpet or other combustible material

other than wood, then the furnace must be installed

on a metal or wood panel extending the full width

and depth of the furnace.

 This furnace is only for use with the type of gas

indicated on the rating plate. This furnace is not

convertible for use with other gases unless a certified

kit is used. If conversion of the unit is needed,

conversions must be performed by a qualified

service provider at the owner’s expense.

 The furnace should be correctly sized for the space it

is required to heat. It is recommended that an

industry standard BTU Heat Loss Calculation be

conducted to determine the proper sizing.

 Follow the installations instructions and those in

section “6. Maintenance” for adequate combustion

and ventilation air.

 This furnace is not designed to be built in.

 DO NOT connect this furnace to a chimney flue

serving a separate solid-fuel burning appliance.

 DO NOT obstruct the flow of combustion and

ventilation air.

Do not use substitute

materials. Use only parts

certified with the furnace.

When installing the direct vent furnace, follow these

guidelines:

 This direct vent furnace is certified for

installation in residential applications,

commercial applications, and manufactured

(mobile) homes.

 This furnace may be installed as an OEM

installation in a manufactured home (USA only)

or mobile home and must be installed in

accordance with the manufacturer’s

instructions and the Manufactured Home

construction and Safety Standard, Title 24

CFR, Part 3280, in the United States, or the

Mobile Home Standard, CAN/CSA Z240 MH

Series, in Canada.

 This furnace may be installed in an aftermarket,

permanently located, manufactured home

(USA only) or mobile home, where not

prohibited by local codes.

 If installation is at a location above 2,001 ft

(610 m), see section “4.4.8 Adjust the Gas

Pressure Settings.”

 Furnace input ratings are based on sea level

operation and need not be changed for

operation up to 2,000 ft (610 m) elevation.

WARNING

Topics in this section

 Installation Guidelines

 What You Will Need

 Choose an Installation Location

 Installation Steps

 Post-Installation Checklist

EX38DT Installation and Operation Manual 11

Unpack the Rinnai Direct Vent Furnace package and verify the following contents are included. If

any items are damaged or missing, contact your local dealer/distributor or call Rinnai Customer

Care at 1-800-621-9419.

4.2 What You Will Need

4.2.1 Items Included

Product Qty Image

Flue Manifold

"A" Vent Kit

(FOT-151)

Spare Rubber

Seal

("A" Flue Units

Only)

Back Spacer

Set

Pipe Stopper

A&S

Insulation Clip 1

Manual Valve 1

Plastic Tie for

Air Inlet

Screw (M5) (For

Wall Brackets)

Screw (M4)

(For Flue

Manifold)

Screw (M4)

(For Back

Spacer Set)

Product Qty Image

Wood Screw

(M 4.8 x 32)

(Wall Bracket

Screws)

Wall Brackets

Flue Adapter

(Attached to

Unit)

Rinnai Direct

Vent Wall

Furnace

Installation and

Operation

1 Image not shown

(For Weatherboard

Installation)

Table 3: Items Included

Name Kit No. Fits Walls

S Vent Kit FOT-150 3 - 4 1/2 in. (75 - 115 mm)

A Vent Kit FOT-151 4 1/2 - 9 1/2 in. (115 - 240 mm)

B Vent Kit FOT-152 9 1/2 - 15 3/4 in. (240 - 400 mm)

C Vent Kit FOT-153 15 3/4 - 23 5/8 in. (400 - 600 mm)

D Vent Kit FOT-154 23 5/8 - 31 1/2 in. (600 - 800 mm)

Vent Kit “A” is included with the furnace.

Additional Flue Manifolds

The following flue manifold sizes are available

for different wall thicknesses:

Table 4: Additional Flue Manifolds

A full size wall template is provided on the furnace carton box. Do not discard until installation is

complete.

IMPORTANT

The color of the back spacers is a slightly different shade than the color of the furnace.

12 EX38DT Installation and Operation Manual

Air surrounding the venting, and vent

termination(s) is used for combustion and must

be free of any compounds that cause corrosion

of internal components. These include corrosive

compounds that are found in aerosol sprays,

detergents, bleaches, cleaning solvents, oil

based paints/ varnishes, and refrigerants.

The furnace, venting, and vent termination(s)

should not be installed in any areas where the

air may contain these corrosive compounds. If it

is necessary for a furnace to be located in

areas that may contain corrosive compounds,

the following instructions are strongly

recommended.

IMPORTANT CONSIDERATIONS:

 DO NOT install in areas where air for

combustion might be contaminated with

chemicals.

 Before installation, consider where air has

the ability to travel within the building to the

furnace.

 Terminate the unit as far away as possible

from any air inlet vents. Corrosive fumes

may be released through these vents

when air is not being brought in through

them.

 Chemicals that are corrosive in nature

should not be stored or used near the

furnace or vent termination.

 Damage and repair due to corrosive

compounds in the air is not covered by

warranty.

 Pipe Wrenches (x2)

 Adjustable Pliers

 Screwdrivers (x2)

 Wire Cutters

 Gloves

 Safety Glasses

 Level

 Soap or Gas Leak Detector Solution

 Approved Venting

 Teflon Tape (Recommended) or Pipe

Compound

The following field-supplied items may be

needed:

 Gas Manometer

 Hammer Drill with Concrete Bits

 Saw

 Threading Machine with Heads and Oiler

 Core Drill with Diamond Head

 Torch Set

 Steel Pipe Cutter

 Concrete Wall Anchors

 Optional Pipe Cover

 Single Gang Electrical Box

 Wire Nuts

4.2.2 Items Needed

(Field-Supplied)

When selecting an installation location, you

must ensure that all direct vent furnace and

venting clearances will be met and that the vent

length will be within required limits. You must

also consider the installation environment.

Requirements for the gas line and electrical

connection can be found in their respective

installation sections in this manual.

4.3 Choose an

Installation Location

4.3.1 Environment

EX38DT Installation and Operation Manual 13

4.3.2 Clearances

AIR SUPPLY INLET

VENT TERMINAL

AREA WHERE

TERMINAL IS NOT

PERMITTTED

Clearance in

Ref. A also

applies to

anticipated

snow line

Flue Terminal Clearances

Figure 5: Flue Terminal Clearances

Table 5: Clearances

[1] A vent shall not terminate directly above a sidewalk or paved

driveway that is located between two single family dwellings and

serves both dwellings.

[2] Permitted only if veranda, porch, deck, or balcony is fully open on

a minimum of two sides beneath the floor.

 For clearances not specified in ANSI Z223.1/NFPA 54, clearances

are in accordance with local installation codes and the requirements

of the gas supplier.

Clearance to opposite wall is 24 inches (60 cm).

Ref

Description

Canadian Installations US Installations

A Clearance above grade, veranda, porch, deck, or balcony 12 inches (30 cm) 12 inches (30 cm)

B Clearance to window or door that may be opened 12 inches (30 cm) 9 inches (23 cm)

C Clearance to permanently closed window * *

Vertical clearance to ventilated soffit, located above the terminal

within a horizontal distance of 2 feet (61 cm) from the center line

of the terminal

* *

E Clearance to unventilated soffit * *

F Clearance to outside corner * *

G Clearance to inside corner * *

Clearance to each side of center line extended above meter/

regulator assembly

3 feet (91 cm) within a height

15 feet (4.5 m) above the

meter/regulator assembly

I Clearance to service regulator vent outlet 36 inches (91 cm) *

Clearance to nonmechanical air supply inlet to building or the

combustion air inlet to any other appliance

12 inches (30 cm) 9 inches (23 cm)

K Clearance to a mechanical air supply inlet 6 feet (1.83 m)

3 feet (91 cm) above if within

10 feet (3 m) horizontally

Clearance above paved sidewalk or paved driveway located on

public property

7 feet (2.13 m) [1] *

M Clearance under veranda, porch, deck, or balcony 12 inches (30 cm) [2] *

14 EX38DT Installation and Operation Manual

When determining where to install the direct vent furnace, the clearances to combustibles shown in

the figures below must be followed.

Clearances to Combustibles

Service Clearances

Clearances to access the furnace during

servicing are 10 in. (254 mm) from the sides,

40 in. (1 m) from the front, and the area shown

above the furnace in the figure to the left.

Rinnai recommends 10 in. (254 mm) clearance

from the top and on both sides for servicing.

Location

Clearances to

Combustibles

Top

0 in. (0 mm)

Bottom/Ground

0 in. (0 mm)

Front (Panel)

40 in. (1 m)*

*Does not include

flooring material or

carpeting less than

1.2 in. (30 mm) in

height.

Back (Including Back

Spacer)

0 in. (0 mm)

Sides (Left and Right) 2 in. (50 mm)

Top

Bottom

Back

If clearances are not met, damage to the property or direct vent furnace may occur.

CAUTION

Table 6: Clearance to Combustibles

Figure 6: Clearances

Measurements: inches (mm)

Figure 7: Service Clearances

Front

6 (153)

10”

(254 mm)

10 (254)

3”

(76 mm)

3 (76)

Side

EX38DT Installation and Operation Manual 15

Use this checklist to ensure you have selected the correct location for the direct vent furnace.

4.3.3 Installation Location Checklist



The furnace is not exposed to corrosive compounds in the air.



The furnace location complies with the required clearances.



The planned venting termination/air intake location meets the clearances.



Indoor air is not being used for combustion.



A standard 3 prong 120 VAC, 60 Hz properly grounded wall outlet is available.



The installation must conform with local codes or, in the absence of local codes, with the

National Fuel Gas Code, ANSI Z223.1/NFPA 54, or the Natural Gas and Propane

Installation Code, CSA B149.1. If installed in a manufactured home, the installation must

conform with the Manufactured Home Construction and Safety Standard, Title 24 CFR,

Part 3280 and/or CAN/SCA Z240 MH Series, Mobile Homes.



Leave the entire manual taped to the furnace or give the manual directly to the

consumer.

16 EX38DT Installation and Operation Manual

4.4 Installation Steps

4.4.1 Drill the Flue Hole

Ensure that there are no gas or water lines, or electrical circuits in the wall location where the flue

hole is to be drilled.

Drill the flue hole using a Ø3 1/8 in. (Ø80 mm) drill. A template is provided on the furnace carton

box. The center of the hole must be located anywhere within the shaded area, unless extension kits

are used. See the dimensions diagram.

For weatherboard walls, drill through the center of the weatherboard from the outside first and then

through the plasterboard.

Figure 8

4.4.2 Attach Wall Brackets

Attach the wall brackets as shown. A template is provided.

Figure 9

Example template located on furnace carton box

Figure 10

Ø3 1/8 in.

(Ø80 mm)

Flue Hole

15/16 in. (24 mm)

1 3/16 in. (30 mm)

28 7/16 in. (723 mm)

23 3/8 in. (593 mm)

Wall Bracket

EX38DT Installation and Operation Manual 17

1. Disassemble the flue manifold

The flue consists of 3 parts:

 sleeve

 inside connection

 outside terminal

Disassemble the flue manifold by first

pulling out the inside connection. To

remove the outer terminal pull and release

the two internal ties and then pull out the

outer terminal.

Clearance to combustibles for the sleeve

and flanges is zero inches.

2. Adjust the sleeve length

Measure wall thickness through previously

drilled Ø3 1/8 inch (Ø80 mm) hole.

The end of the sleeve should protrude 3/16 -

3/8 inch (5-10 mm) from the outside wall.

The sleeve is threaded for adjustment.

Adjust the sleeve length to wall thickness

plus 3/16 - 3/8 inch (5-10 mm).

NOTE: Do not extend beyond the red line.

For other than the “S” type flue manifold, if a

shorter length is necessary an extension can

be removed. Cut the outer plastic laminate

(with a utility knife or similar) and remove the

extension. The metal should not be cut.

Inside Connection

Sleeve

Terminal

Remove extension

if necessary

Guidelines:

 The flue manifold must exhaust to the

outside. Do not exhaust into other

rooms.

 The flue manifold is not designed to be

positioned under floors or below the

furnace.

 The termination cannot be vertical.

 This furnace can only be used with one

of the five types of Rinnai flue kits. The

flue kits and their dimensions are listed

in section “4.2.1 Items Included.”

 Refer to “Flue Terminal Clearances” in

section “4.3.2 Clearances.”

4.4.4 Install the Flue

Manifold

Instructions:

Figure 13

Figure 12

4.4.3 Attach Back Spacers

Attach side back spacers to both sides of the

furnace with 2 screws each.

Figure 11

18 EX38DT Installation and Operation Manual

3. Install the Sleeve.

Attach the sleeve to the inside wall using 3 screws arranging the flange so that the marking

“TOP” is at the top. The flange is offset 2° to allow the condensate drain to the outside.

Apply silicone sealing evenly around the perimeter of the outside sleeve to avoid water intrusion.

4. Install the Terminal.

Check that the terminal seal is in place. For weatherboard walls, add the second seal next to the

terminal seal to compensate for weather board angle. Adjust the second seal to make sure “Top”

marking of the second seal is located at the top or “Ʌ” marking is aligned with “V” marking on the

terminal.

From the outside insert the terminal into the sleeve with the marking “TOP” at the top. The left

hand side locking tie should be marked “LEFT”.

3 screws

Sleeve should extend

3/16 - 3/8 in (5-10 mm)

Figure 14

Indoor

Outdoor

Apply silicone

sealing evenly

around the

perimeter.

Top Terminal

seal

Apply silicone

sealing evenly

around the entire

seal.

Put silicone sealing evenly around the perimeter without any

gaps between the terminal seal and rough wall surface.

Figure 15

Locking tie

(Ʌ)

(V)

Terminal

EX38DT Installation and Operation Manual 19

5. Lock the ties.

Pulling hard on the left and right hand ties, clip the ties over the notches inside the sleeve. You

should be able to pull the ties 2 or 3 notches past the starting point. Cut the ties, leaving about

1 1/4 inch (30 mm) past the notch. Bend the ties back into the sleeve and parallel to the wall.

6. Insert Inside Connection Assembly.

Push the assembly into the terminal tube, ensuring that the seal is in place on the inner tube.

Attach the inside connection with 3 screws. The inner connection can still be turned to install the

screws.

3 screws

Figure 17

Locking ties

Sleeve

Figure 16

Top

Sleeve

Clip the ties over

the inside sleeve

and cut the ties

sticking out.

Pull hard on the left and right hand ties.

Locking ties (2 locations)

Locking tie

20 EX38DT Installation and Operation Manual

4.4.5 Install the Optional Extension Kit

Item Description Part Number

Extension Kit Part Number

FOT-102 FOT-103 FOT-114 FOT-115

1 Exhaust Pipe (adjustable)

12.2-21.1 in. (311-536 mm)

FOT 111-1 1

1 Exhaust Pipe (adjustable)

21.9-40.4 in. (556-1,026 mm)

FOT 112-1 1 1

2 Exhaust Pipe - 39.4 in. (1,000 mm) FOT 114-3 1

3 Air Intake Hose - 29.5 in. (750 mm) RHF 1000-130-e 1

3 Air Intake Hose - 51.2 in. (1.3 m) RHF 1000-130-b 1

3 Air Intake Hose - 90.6 in. (2.3 m) RHF 1000-130-f 1

4 Bent Elbow FOT 025-4 1

5 Hose Joint RFOT 226-001 1 1 1

6 Pipe Stopper A 1001F-250 1 1 2 2

7 Pipe Stopper B FOT 111-6 1 1 1

8 Top Stopper FOT 062-7 1 1 1

9 Pipe Clamp FOT 064-11 2 Sets 3 Sets 4 Sets

10 Wall Fixture FOT 064-12 2 3 4

11 Nut FOT 062-10 2 3 4

12 Screw A ZAA0420SC 2 3 4

13 Screw B CP-30408 4 6 8

Extension kits are available to extend the exhaust line and air intake hose between the manifold and

direct vent furnace. Follow the steps in this section if the optional extension kit was purchased for

your Direct Vent Furnace model.

Extension Kit Contents

Verify the following contents are included in the extension kit:

Table 7: Extension Kit Contents

Figure 18

❶

❾ ❻

❸

❷

❺

❹

❽

❼

⓬

⓫

⓭

❿

EX38DT Installation and Operation Manual 21

Guidelines

1. The maximum vent length is 13 feet (4 m) with 3 bends. The bent pipe attached to the furnace

does not count toward the max limit of 3 bends.

2. Horizontal sections should be sloped 3º to drain condensate. (3º equals 2/3 inch drop per foot of

vent.) The direction should be to the outside (if local codes allow) or toward the furnace.

3. Do not allow any low points in the exhaust line where condensate will collect.

4. Vent extensions installed in unconditioned air space.

5. Clearances:



Exhaust pipe to combustibles: 1 in. (25.4 mm)



Exhaust pipe to non-combustibles: 0 in. (0 mm)

Figure 19

NOTE

Configurations

The EX38DT is capable of two vent length

settings:

 Short Vent: 0 - 7 ft + 1 elbow

 Long Vent: 7 ft + 1 elbow - 13 ft + 3 elbows

Slope horizontal sections 3º (2/3 inch drop per foot of vent.)

3°

1 Ft

2/3 in.

Correct Configurations

Figure 20

22 EX38DT Installation and Operation Manual

 Too many bends (limit is 3)

 Air intake hose is above

exhaust pipe.

Do not allow any low points in the exhaust line.

Incorrect Configurations

NOT CORRECT

Back of Furnace

NOT CORRECT

CORRECT

NOT CORRECT

Figure 21

Figure 22

Figure 23

90° Elbow Up

Configuration

Slope horizontal

sections 3°

downward

3°

Intake

Exhaust

Intake

Exhaust

EX38DT Installation and Operation Manual 23

Use the pipe stoppers, connectors, clamps,

and screws according to these instructions in

order to ensure no leakage of exhaust gases.

Exhaust pipe

Air intake hose

Pipe stopper A

Pipe stopper B

Male end

Female end

Adjust the angle

Hose joint

Air intake hoses

Do not cut the intake hose. Cutting the

intake hose may result in noise.

Instructions:

1. Install the Clamps:

Both the exhaust line and air intake hose

are supported by clamps which are attached

to the wall. A wall fixture can be used to

offset the clamp from the wall. Use Screw B

to attach the wall fixture to the wall. If the

wall fixture is not used then use Screw A

and the nut to attach the clamp to the wall.

The air intake hose should always be

underneath the exhaust line so that in case

the air line sags it will not come into contact

with the exhaust line.

2. Install the Exhaust Line:

The exhaust line is connected between the

bent pipe at the rear of the furnace and the

exhaust port on the flue manifold.

 To connect exhaust pipes with other

straight pipes or bends, fit the male end

into the female end. Use pipe stopper A

to clamp the connection.

 Use pipe stopper B to fix the length on

the adjustable exhaust pipes. Do not

extend these pipes beyond the red line.

 Do not cut the exhaust pipe. Use the

adjustable pipes if necessary.

 To bend the elbow, insert exhaust pipes

into both ends for additional leverage.

Bend to desired angle.

 Do not straighten the bent pipe attached

to the furnace.

3. Connect the Air Intake Hose:

The air intake hose is connected between

the air connection at the rear of the furnace

and the air intake port on the flue manifold.

Push the air intake hose onto the flue

manifold and secure with the plastic cable

tie.

Join air intake hoses by screwing the hose

joint half of its length into the air intake hose

and then screwing another air intake hose

into the hose joint.

The lengths of the air intake hose and the

exhaust pipe must be the same in order for

the furnace to operate properly. The hose

can be cut to the required length. Deburr all

rough edges. Do not cut the hose attached to

the furnace.

Support the air intake hose with pipe clamps.

NOTE

CAUTION

Figure 26

Figure 25

Figure 24

24 EX38DT Installation and Operation Manual

4.4.6 Connect the Direct Vent Furnace

1. Attach flue adapter to the flue manifold with

pipe stopper S.

2. Attach the air inlet hose to the flue

manifold. Secure with plastic tie. The

unused inlet is plugged with the rubber cap

supplied on the manifold.

3. Connect the vent sliding tube with pipe

stopper S and A.

4. Slide the insulation sleeve up to the flue

manifold and slip the securing clip over the

sleeve as shown.

5. Attach the furnace to the wall brackets,

using 2 screws at each bracket.

6. Attach the back spacer with 3 screws to the

top of the furnace.

7. If necessary, the furnace can be leveled

using the adjustable legs under the front

right and left legs.

Up to

3/8 in.

(10 mm)

Adjustable Leg

Pipe Stopper S

Flue Adapter

Flue Manifold

Plastic Tie

Inlet Hose

Inlet

Elbow

Flue Manifold

Sliding Tube

Pipe Stopper A

Pipe Stopper S

Figure 28

Figure 27

Figure 29

Figure 31

Figure 30

Screw

(M5)

Figure 32

Insulation

Sleeve

EX38DT Installation and Operation Manual 25

4.4.8 Adjust the Gas

Pressure Settings

 The gas supply line shall be gas tight,

sized and so installed as to provide a

supply of a gas sufficient to meet the

maximum demand of the furnace without

loss of pressure.

 A shut off valve and appliance connector

valve should be installed in the upstream

of the gas line to permit servicing.

 Flexible pipe and any appliance connector

valve used for gas piping shall be types

approved by nationally recognized

agencies.

 Any compound used on the threaded joint

of the gas piping shall be a type which

resists the action of liquefied petroleum

gas (propane).

 After completion of gas pipe connections

all joints including the furnace must be

checked for gas tightness by means of

leak detector solution, soap and water, or

an equivalent nonflammable solution, as

applicable. (Since some leak test

solutions, including soap and water, may

cause corrosion or stress cracking, the

piping shall be rinsed with water after

testing, unless it has been determined that

the leak test solution is non-corrosive.)

 Check the gas supply pressure

immediately upstream at a location

provided by the gas company. Supplied

gas pressure must be within the limits

shown in section “3.2 Specifications.”

 Refer to an approved pipe sizing chart if in

doubt about the size of the gas line.

Complete these instructions for altitude and

vent length.

 Default altitude: 0 - 2,000 ft.

 Default vent length: 0 - 7 ft. + 1 Elbow

 For altitudes greater than 2,000 ft or

installations with vent lengths longer than

7 ft, refer to Table 8: Gas Pressure on the

next page.

For high altitude installations in Canada, the

conversion shall be carried out by a

manufacturer’s authorized representative, in

accordance with the requirements of the

manufacturer, provincial or territorial authorities

having jurisdiction and in accordance with the

requirements of CAN/CGA-B149.1 or CAN/

CGA-B149 installation codes.

4.4.7 Connect the Gas

When connecting the gas valve or other gas

components in the gas line, use a backup

wrench to ensure the connection is gas tight.

WARNING

CAUTION

 Do not touch any other areas on the PC

board besides the “SW” switches while

power is supplied to the furnace. Parts

of the PC board are supplied with 120

volts AC.

 Do not insert hands or objects into the

circulation fans while they are running.

Injury or mechanical malfunction may

occur.

 Do not touch the areas at or near the

exhaust. This area becomes very hot

and could cause burns.

The regulator has been factory pre-set. If

the pressure is incorrect, contact Rinnai

technical support.

IMPORTANT

26 EX38DT Installation and Operation Manual

Instructions:

Natural Gas

 Short Vent Lengths:

0 - 7 ft (2 m) + 1 elbow (A1 - A4)

 Long Vent lengths:

7 ft (2 m) +1 elbow - 13 ft (4 m) + 3 elbows (A5 - A8)

Propane Gas

 Short Vent Lengths:

0 - 7 ft (2 m) + 1 elbow (L1 - L4)

 Long Vent lengths:

7 ft (2 m) +1 elbow - 13 ft (4 m) + 3 elbows (L5 - L8)

Code A1 / A5 A2 / A6 A3 / A7 A4 / A8 L1 / L5 L2 / L6 L3 / L7 L4 / L8

Altitude

0-2,000 ft

0-610 m

2,001-5,400 ft

611-1,646 m

5,401-7,800 ft

1,647-2,377 m

7,801-10,200 ft

2,378-3,109 m

0-2,000 ft

0-610 m

2,001-5,400 ft

611-1,646 m

5,401-7,800 ft

1,647-2,377 m

7,801-10,200 ft

2,378-3,109 m

Manifold test

pressure - W.C.

Low

1.69 in.

(43 mm)

1.59 in.

(40 mm)

1.49 in.

(38 mm)

1.43 in.

(36 mm)

3.21 in.

(82 mm)

3.01 in.

(76 mm)

2.85 in.

(72 mm)

2.73 in.

(69 mm)

Manifold test

pressure - W.C.

High

3.8 in.

(96 mm)

3.0 in.

(76 mm)

2.7 in.

(68 mm)

2.5 in.

(62 mm)

6.4 in.

(162 mm)

5.6 in.

(143 mm)

5.1 in.

(129 mm)

4.6 in.

(116 mm)

1. Turn off the gas and the power

supply.

2. Remove the 3 screws that hold the

front panel. Lift the panel straight up

and then remove.

3. Remove test port screws (1/8 NPT

tap) with 3/16 Allen wrench located

at gas valve and burner cover.

Install two 1/8 in. barb fittings (field-

supplied). Attach dual port

manometer to the test ports as

shown. Ensure that the manometer

is properly calibrated.

4. Turn on the gas and power supply

to the furnace.

5. Ensure “Set Back” feature has been

deactivated. (“Set Back” feature is

active by default.)

6. With the unit in the Off position,

press the Test Switch at the bottom,

right of PC board until it beeps.

7. Select the correct code for gas type,

altitude, and vent length on the LED

display using ▲ and ▼ buttons.

Refer to the table below.

Table 8: Gas Pressure

Figure 33

Negative

Port

Positive

Port

PCB Test

Switch

EX38DT Installation and Operation Manual 27

8. Press the Test Switch twice to enter the

gas code into memory.

The LED display turns blank and the unit

returns to the normal off mode. You are

now ready to program your correct low

fire and high fire gas pressure setting.

Follow the procedure below for setting

the manifold gas pressure. Do not adjust

gas pressure on this furnace using the

screw on top of the gas valve.

9. Press the ON/OFF button to operate the

furnace.

10. Press the Test Switch twice to change to

the low pressure mode. The LED will

display “PL”.

11. Compare the pressure reading on the

manometer to the desired manifold test

pressure (low) for your gas type, altitude

and vent length. If necessary adjust the low

fire pressure using the ▲ and ▼ buttons.

12. Press the Test Switch. The LED will display

“PH” indicating high fire mode.

13. Compare the pressure reading on the

manometer to the desired manifold test

pressure (high) for your gas type, altitude

and vent length. If necessary adjust the

high fire pressure using the ▲ and ▼

buttons.

14. Press the ON/OFF button again. The LED

display turns blank and the furnace returns

to the normal OFF mode.

15. Remove manometer and two barb fittings,

and install Allen head screws. Operate the

unit and follow steps A, B, and C below.

A. Check for Gas Leaks at the Test

Points.

16. Install the front panel.

17. If doing a gas type conversion, place the

new conversion rating plate (label) on the

front cover.

B. Check the Normal Operating

Sequence:

When you press the ON/OFF button,

the LED display will illuminate, the

combustion fan will begin to run, and

the spark will ignite the main burner.

This furnace has an automatic

ignition system. When the main

burner has lit, the combustion lamp

will glow red, and the spark will stop.

C. Visually Inspect the Flame:

Check that the burner flames are

operating normally. The flame can be

seen through the circular window.

When operating normally the burner

flame should appear as long, clear,

blue, stable, streaks. Yellow flames

or an orange color is abnormal and

maintenance is required.

NORMAL

ABNORMAL

Yellow or

orange flames

Flame Rod

Long, clear, blue,

stable flames

Flame Rod

Figure 34: Normal and Abnormal Flames

28 EX38DT Installation and Operation Manual

4.5 Post-Installation Checklist

INSTALLATION LOCATION YES NO

Have you verified the unit and vent termination meet the clearance requirements?

 

COMBUSTION AIR AND VENTING YES NO

Have all corrosive compounds been removed from around the direct vent furnace?  

Are the correct venting products for the installed model being utilized? Have you

completely followed the installation instructions in this manual?

 

Have you verified the vent system does not exceed the maximum length for the

number of elbows used?

 

GAS SUPPLY YES NO

Has a manual gas control valve been placed in the gas line to the furnace?

 

Have you checked the gas lines and connections for leaks?

 

Have you confirmed that the gas inlet pressure is within limits?

 

Did you confirm that the furnace is rated for the gas type supplied?

 

Have you verified the system is functioning correctly by connecting your manometer to

the gas pressure test port on the furnace?

 

Did you operate all gas appliances in the home or facility at high fire?

 

Did you verify that the inlet gas pressure at the furnace did not drop below that listed

on the rating plate?

 

ELECTRICITY

YES NO

Did you confirm that the electricity is supplied from a 120 VAC, 60 Hz power source, is

in a properly grounded circuit, and turned on?

 

Have you confirmed that an extension cord or an adapter plug has NOT been used

with the furnace?

 

FINAL ITEMS

YES NO

Did you install the front panel?

 

Have you explained to the customer the importance of not blocking the vent

termination?

 

Have you explained to the customer the operation of the furnace, safety guidelines,

maintenance, and warranty?

 

Did you leave the manual with the customer?

 

Does the installation conform with local codes or, in the absence of local codes, with

the National Fuel Gas Code, ANSI Z223.1/NFPA 54, or the Natural Gas and Propane

Installation Code, CSA B149.1? If installed in a manufactured home, the installation

must conform with the Manufactured Home Construction and Safety Standard, Title 24

CFR, Part 3280 and/or CAN/SCA Z240 MH Series, Mobile Homes.

 

Complete the following checklist when installation is complete. You should be able to answer YES to

each question. If you answer NO to any question, installation is not complete. Refer to the applicable

section in this manual for additional information. For assistance, contact your local dealer or

distributor, or call Rinnai Customer Care at 1-800-621-9419.

EX38DT Installation and Operation Manual 29

5. Operation

5.1 Safety

Precautions



—Iftheinformaoninthese

instruconsisnotfollowedexactly,

aﬁreorexplosionmayresult

causingpropertydamage,personal

injuryordeath.

— Donotstoreorusegasolineorother

ﬂammablevaporsandliquidsinthe

vicinityofthisoranyother

appliance.

— WHATTODOIFYOUSMELLGAS

 Donottrytolightanyappliance.

 Donottouchanyelectrical

switch;donotuseanyphonein

yourbuilding.

 Immediatelycallyourgas

supplierfromaneighbor’s

phone.Followthegassupplier’s

instrucons.

 Ifyoucannotreachyourgas

supplier,calltheﬁre

department.

— Installaonandservicemustbe

performedbyalicensed

professional.

WARNING

 Keep the area around the furnace clear

and free from combustible materials,

gasoline, and other flammable vapors

and liquids.

 Do not use this furnace if any part has

been under water. Immediately call a

trained and qualified professional to

inspect the furnace and to replace any

part of the control system and any gas

control which has been under water.

 Do not operate furnace with the panels

removed, cracked or broken.

WARNING

 Do not block the warm air discharge. Do

not allow anyone to sleep directly in front of

the furnace.

 Children and adults should be alerted to

the hazards of high surface temperature

and should stay away to avoid burns or

clothing ignition.

 Young children should be carefully

supervised when they are in the same

room as the furnace.

 Clothing or other flammable material

should not be placed on or near the

furnace.

 Any safety screen or guard removed for

servicing must be replaced prior to

operating the furnace.

 Do not insert items into the louvers.

 Do not spray aerosols near the furnace

while it is operating. Most aerosols contain

butane gas which is flammable.

 Do not unplug the furnace while it is

operating or while the fans are on.

 Do not use bare hands to touch the front

louvers due to high temperatures which

may cause burns.

 Wear hand protection when touching the

side back covers, front louver, and rear

intake for the convection fan.

 Prevent dust from accumulating on the

power cord, side covers, and parts behind

the furnace.

 Do not sit on the furnace.

 Do not place containers of liquid on top of

the furnace. Water spillage can cause

extensive damage to the furnace and may

result in electric shock.

CAUTION

Topics in this section

 Safety Precautions

 Operating Instructions

 Control Panel

 Basic Operation Settings

 Add Water to the Humidifier

 Adjust Air Flow Direction

 Restart Function

 Diagnostic Codes

30 EX38DT Installation and Operation Manual

FOR YOUR SAFETY READ BEFORE OPERATING

WARNING

If you do not follow these instructions exactly, a fire or explosion

may result causing property damage, personal injury or loss of life.

A. This appliance does not have a pilot. It is equipped

with an ignition device which automatically lights the

burner. Do not try to light the burner by hand.

B. BEFORE OPERATING smell all around the

appliance area for gas. Be sure to smell next to the

floor because some gas is heavier than air and will

settle on the floor.

WHAT TO DO IF YOU SMELL GAS:

 Do not try to light any appliance.

 Do not touch any electric switch; do not use any

phone in your building.

 Immediately call your gas supplier from a

neighbor’s phone. Follow the gas supplier’s

instructions.

 If you cannot reach your gas supplier, call the fire

department.

C. Use only your hand to push in or turn the gas

control knob. Never use tools. If the knob will not

push in or turn by hand, do not try to repair it, call a

qualified service technician. Force or attempted

repair may result in a fire or explosion.

D. Do not use this appliance if any part has been

under water. Immediately call a qualified service

technician to inspect the appliance and to replace

any part of the control system and any gas control

which has been under water.

OPERATING INSTRUCTIONS

TO TURN OFF GAS TO APPLIANCE

5.2 Operating Instructions

1. STOP! Read the safety information above.

2. Set the thermostat to lowest setting.

3. Turn off all electric power to the appliance using the

ON/OFF button on the control panel.

4. This appliance does not have a pilot. It is equipped

with an ignition device which automatically lights

the burner. Do not try to light the burner by hand.

5. Turn Manual valve clockwise to the full OFF

position.

6. Wait five (5) minutes to clear out any gas. Then

smell for gas, including near the floor. If you smell

gas, STOP ! Follow “B” in the safety information

above. If you don’t smell gas go to the next step.

7. Turn the manual gas valve counterclockwise

to the full ON position.

8. Turn on all electric power to the appliance using the

ON/OFF button.

9. Set the thermostat to desired setting.

10. Burner is lit when indicator lamp “ON” turns red.

11. “ON” indicator is lit and fault code 11 flashes when

burner fails to ignite.

12. If the appliance will not operate, follow the

instructions “To Turn Off Gas To Appliance” and

call your service technician or gas supplier. See

manual for additional information.

1. Set the thermostat to lowest setting.

2. Turn off all electric power to the appliance if service

is to be performed (Using the ON/OFF button

located on control panel.)

3. Locate the manual gas valve.

4. Turn the manual valve clockwise to the full

OFF position.

NOTE: The fan will continue to operate until the

appliance is cool. Do not turn the appliance off by

unplugging it from the wall. Keep burner and control

compartment clean. See installation and operating

instructions.

Display

ON Indicator

ON/OFF

Button

Up/Down

Buttons

EX38DT Installation and Operation Manual 31

The direct vent furnace includes a controller integrated into the front cover. Each feature on the

control panel is described in the following sections.

5.3 Control Panel

Sensible Temperature Control

The sensible temperature control feature allows comfortable heating which matches the conditions in

the room.

Based on the information collected by the room temperature thermistor when the heating starts, the

heating capacity is automatically adjusted to achieve a comfortable heating effect and to reach the

temperature setting quickly.

Occasionally, the room temperature may briefly exceed the temperature setting due to the layout of

the room or heating area.

After the furnace is turned on and begins operating, the display will dim. The display will turn off

when the furnace is turned off. While programming the timers the display will turn off several sec-

onds after a button is last pushed.

Display

Note: The factory default is °F.

1. The furnace must be turned off.

2. Press the Timer 1 and Timer 2 button at the same time for about 5 seconds. The display will

show “ºC” or “ºF”.

3. Use the arrow keys to select the temperature scale.

4. Press the ON/OFF button.

Fahrenheit or Celsius

Press the ON/OFF button to operate the furnace. The ON indicator will glow green.

Once the burner ignites the ON indicator will glow red. When the furnace warms

up, the fan will automatically start.

To turn the furnace off, press the ON/OFF button. The ON indicator light will go

out. The fan will continue to operate for several minutes after the burner has gone

out in order to cool the furnace. Do not unplug the furnace while the fan is running.

5.4 Basic Operation Settings

5.4.1 On/O

Figure 35: Control Panel

Figure 36

32 EX38DT Installation and Operation Manual

The Lock feature will help to prevent accidental

operation of the furnace and to prevent

children from operating the furnace.

To activate Lock, press the Lock button. The

indicator will light and a beep will sound.

To deactivate Lock, press the Lock button and

hold for about 2 seconds. The indicator light

will go out and a beep will sound.

 The lock can be activated when the

furnace is ON or OFF.

 If activated while the furnace is ON, all

controls other than the OFF switch will be

locked.

 If activated while the furnace is OFF, then

all controls will be locked.

 If the furnace is turned off while the Lock is

activated, it cannot be turned on again until

the lock is deactivated.

 Deactivating the lock releases the control

buttons.

1. Press the “Program” button.

2. The light next to “Clock” should be flashing.

Press the up and down arrows to set the

time. Holding down either of the arrow keys

will change the time more quickly.

3. Press the “Program” button until none of

the time options are flashing.

1. Turn the furnace on by pressing the “ON/

OFF” button.

2. Press the up or down arrows to set the

temperature. The left side of the display

shows the temperature setting. The right

side of the display shows the room

temperature.

5.4.2 Lock

5.4.4 Operate the Furnace

Manually

5.4.3 Set the Clock

Figure 38

Figure 37

Figure 40

Figure 39

Figure 41

The thermostat automatically modulates the

burner and the fan to maintain the

temperature setting.

The temperature settings available are:

 L - burner is on minimum combustion

 60-80ºF (16-26°C) in 2ºF (1°C)

Increments

 H - burner is on maximum combustion

EX38DT Installation and Operation Manual 33

ECONOMY

PROGRAM

00 - Default Factory Setting

01 - Remote Thermostat Mode

02 - Control Panel Mode

The following buttons/indicators on the control panel will remain functional in either mode:

 ON/OFF Button

 FILTER Indicator

 ON Indicator

 DISPLAY (The DISPLAY will be blank except in the event of an error code. All error codes will

show on the DISPLAY in either mode. Error codes will not show on the remote thermostat even

when in remote thermostat mode.)

A remote thermostat can be installed for the furnace with the Remote Thermostat Installation Kit

(Part # 204000045 for US installations, Part # 204000048 for Canadian installations). Once

installed, the furnace must be placed in Remote Thermostat mode by following the steps below:

1. Ensure the furnace is plugged in but is turned OFF.

2. Ensure the Set back feature is turned OFF.

3. Press and hold the Economy + Up + Program buttons for 2.5 seconds and then release (00

appears in the display).

4. Press the UP button (01 appears in the display).

5. Press the ON/OFF button; the display will go blank. The furnace is now in Remote Thermostat

mode.

Do not unplug the furnace within two hours of entering Remote Thermostat mode. This will cause

the furnace to revert back to the Default Factory Setting.

Note: To return the furnace back to Control Panel mode, repeat steps 1-3. At step 4, press the UP

button until 02 appears in the display. Next, press the ON/OFF button; the display will go blank. The

furnace is now in Control Panel mode.

5.4.5 Remote Thermostat Mode (Optional Accessory)

IMPORTANT

The remote thermostat will NOT control the furnace’s ability to power on or power down. This

must still be done by using the ON/OFF button of the furnace.

IMPORTANT

DO NOT place furnace into 01 (Remote Thermostat Mode) without wall thermostat connection

components. Failure to do so may cause improper operation of the unit.

IMPORTANT

Figure 42

34 EX38DT Installation and Operation Manual

This function is used only when the furnace is

in Timer operation.

It allows you to “override” the reset timer

setting until the beginning of the next Timer

period.

For example, if the furnace is ON, pressing

the “Override” button will turn the furnace OFF

until the next period. If the furnace is OFF,

pressing the “Override” button will turn the

furnace ON, and allow you to select a

temperature setting, until the next period. The

furnace will remain on until the next timer

period or until the Override function is turned

off.

5.4.7 Override Function

5.4.6 Setting and Operating

the Timers

Figure 48

Confirm the clock is correct.

NOTE: The clock will have to be reset in case

of a power failure. However the timers will retain

their settings.

The furnace will start before the programmed

starting time in order to heat the room by the

programmed starting time.

The timers can be set while the furnace is on or

off. To operate the timer, the furnace must be

on.

Setting the timers:

2. The light next to “Timer 1 on” should be

flashing. Press the up or down arrows to set

the start time. Holding down either of the

arrow keys will change the time more quickly.

Operating the timers:

To operate the furnace using a Timer, press

the ON/OFF button and the appropriate Timer

button. The furnace will operate from the start

to end times you have entered for that Timer. It

will operate at the temperature setting that has

been set for the furnace. The timer can be set

while the furnace is operating.

Figure 43

While in standby, the timer LED will be on with

a solid light. When operating the LED will be

flashing.

Figure 47

4. Press the “Program” button again so that the

Timer 1 Temp Position is flashing. Press the

up or down arrows to set the temperature.

Figure 44

3. Press the “Program” button again so that

the Timer 1 off position is flashing. Press

the up or down arrows to set the end time.

Holding down either of the arrow keys will

change the time more quickly.

Figure 45

1. Press the “Program”

button twice to set Timer 1.

5. Press the “Program” button again to

set the times for Timer 2. Follow the

same steps above to set the start and

end times.

6. Press the “Program” button until none

of the time options are flashing up.

9:00

6:00

Flashing

When in override function,

pressing the “Override” button

will return the furnace to the

operation of the current timer

period.

Figure 46

EX38DT Installation and Operation Manual 35

The Set Back feature is intended to prevent

the installation location from falling below a

specified temperature. It is not intended as an

alternate thermostat, but rather a preventative

measure against freezing.

The Economy mode can only be

set while the furnace is

operating (heating). Once it is

set, it will remain in the system

memory until deactivated.

1. To turn the Economy mode

on, press the “Economy”

button. The Economy

indicator is lit.

This function allows a minimum room

temperature to be pre-set, between 38ºF and

78ºF (in 1ºF increments) This temperature

should be set below the room temperature

setting. The default setting is 60ºF. Once the Set

back function is selected the furnace will start

heating whenever the room temperature falls

below the selected temperature, regardless of

timer or manual settings.

Follow these steps to set and operate the Set

back feature:

1. Make sure the furnace is

turned OFF.

2. Press the “Set back” button.

The light above the button will

come on.

3. Press the up and down buttons to set the

minimum temperature.

When the “Set back” indicator is on, frost

protection is operating, and will always prevent the

room temperature from falling below the pre-set

minimum temperature (as long as electric power

and gas is supplied).

To turn this feature off, press the “Set back” button.

The unit will retain its ON or OFF setting after a

power failure. (Default setting at the factory is on.)

5.4.9 Set Back

5.4.8 Economy (Energy

Saving Mode)

IMPORTANT

Figure 50: Economy Mode

Figure 53

Figure 51

Figure 49

 The Economy mode now remains in the

system memory.

 If the furnace is turned off manually, or

stops heating as a result of an OFF timer

period, the “Economy “ indicator will go

out.

 Whenever the furnace starts heating

again, the “Economy” indicator will light.

2. To turn the Economy mode off, press the

“Economy” button. The “Economy “

indicator will go out.

 The Economy mode can only be turned

off while the furnace is operating

(heating) and when the “Economy”

indicator is lit.

Economy Mode Information

After the room is heated initially, the air

temperature may be dropped to a lower level

without affecting comfort. The Economy Mode

reduces the temperature by 2 ºF, 30 minutes

after the room temperature setting is reached.

After another 30 minutes, it reduces the

temperature setting by another 2 ºF, effectively

saving energy. The room temperature setting

will drop up to a total of 4 ºF.

The Economy Mode will not operate if the

furnace is under capacity for the room size.

Figure 52

36 EX38DT Installation and Operation Manual

If there is a power failure while the furnace is

on, then the furnace will start automatically

when the power is restored.

If the furnace fails to ignite, the furnace will

attempt ignition after 1 hour. The “Ignition

Failure” fault code, 11, will appear during that

hour and disappears after a successful ignition.

If ignition fails again, then the fault code will

remain and another attempt to ignite will occur

in 1 hour. The fault code is not stored in the

fault code history.

If the flame is extinguished during forced

combustion then the furnace will attempt

ignition after 1 hour. The “Ignition Failure” fault

code, 11, will appear during that hour and

disappears after a successful ignition. Forced

combustion takes place for about 40-80

seconds after ignition. After this time, the

temperature control logic controls the

combustion.

If the flame is extinguished (burner combustion

failure) while the temperature control logic is

operating the furnace, then the furnace will

immediately attempt ignition. No fault code will

appear.

In summary, if the ignition fails or the flame is

extinguished during forced combustion then the

furnace will attempt to restart after 1 hour. If the

flame is extinguished after this period then the

furnace will immediately attempt ignition.

The vertical louvers may be adjusted to move

the air flow more to the right or to the left.

Use a screw driver or similar object to bend

each louver to the desired position.

To fill the tray, open the door as shown in the

illustration and pour water into the tray up to the

Max Fill Line using the spout built into the door.

The air will be humidified as it passes over the

water in the tray.

During operation a small amount of

condensation is produced in the flue system

and drains into the humidifier tray.

5.6 Adjust Air Flow

Direction

5.5 Add Water to

the Humidiﬁer

5.7 Restart Function

Do not fill the tray while the furnace is in

operation. Close the door after filling. The

humidifier tray and surrounding area are hot

when the furnace is on.

CAUTION

Do not adjust the air flow louvers while warm

air is flowing.

CAUTION

Figure 55

Do not bend repeatedly (no more than 5 times)

or else the louver may break.

The horizontal louvers (which determines the

vertical air flow direction) are fixed and cannot

be adjusted.

Figure 54

Max

Fill Line

Access

Door

PULL

Filler Spout: Do not force door open too far.

Close door during operation.

Humidifier

Tray

EX38DT Installation and Operation Manual 37

5.8 Diagnostic Codes

If there is a malfunction the furnace may shut down as a safety precaution and display a fault code to assist in

diagnosing the problem. The fault code will flash in the display on the control panel. When making a service

call, this code will assist with diagnosing the fault.

You may be able to clear the fault code by turning the furnace off and then on again. If the fault code remains

or returns on the next operation, contact Rinnai or your nearest service agent and arrange for a service call.

Table 9: Diagnostic Codes

WARNING

Some of the checks below should be performed by a trained and qualified professional.

Consumers should never attempt any action that they are not qualified to perform.

CODE

DISPLAYED

FAULT REMEDY

11 [3] No Ignition

Check that gas is turned ON.

Check that the vent termination is not blocked.

Refer to section “5.7 Restart Function.”

Service call if repeated.

14 Overheat

Clean filter.

Service call if repeated. [1]

Room Overheat

(More than 104°F/40°C)

Lower the room temperature.

Overheat Temperature Thermistor 2

Disconnection (open circuit)

Room Temperature Thermistor

Disconnection (Open Circuit)

Room Temperature Thermistor

Short Circuit

Overheat Thermistor 1

Disconnection (Open Circuit)

Overheat Thermistor 1

Short Circuit

Overheat Temperature Thermistor 2

Short Circuit

40 Pressure Sensor Sensing Tube Failure

49 Pressure Sensor Breakdown

53 Abnormal Spark Sensed

61 Combustion Fan

62 Convection Fan

70 ON/OFF Switch or “Set Back” Switch

71 Solenoid Valve Failure

72 Flame Rod Failure

73 Communication Error

81 Solenoid Valve

99 Flue Block Check around the flue terminal for blockage. [2]

Service Call

[1] If the fusible link needs replacement, it must be done by a qualified service agency. In addition, the

cause of the overheat needs to be determined. The fusible link is a one use safety device that breaks to

shut off the furnace.

[2] Remove any obstructions. The flue needs to be kept clear to expel exhaust gases. If the furnace fails to

operate contact a qualified service agency.

[3] The display of code 11 is dimly flashing.

38 EX38DT Installation and Operation Manual

Filters

Dirty filters reduce the

air flow and the

furnace’s ability to

produce heat. The

filters should be

cleaned frequently

during the heating

season.

If the filters become

blocked, the filter

indicator lamp will flash

red and a beep will

sound five times.

Visual Inspection of Flame

Check that the burner flames are operating normally.

The flame can be seen through the circular window.

When operating normally the burner flame should

appear as long, clear, blue, stable, streaks. Yellow

flames or an orange color is abnormal and

maintenance is required.

NORMAL

 This direct vent furnace must be inspected

annually by a trained and qualified

professional. Repairs and maintenance must

be performed by a trained and qualified

professional. The trained and qualified

professional must verify proper operation

after servicing.

 More frequent cleaning may be required due

to excessive lint from carpeting, bedding

material, etc. It is imperative that control

compartments, burners, and circulating air

passage ways of the furnace be kept clean.

 Any screen or guard removed for servicing

the furnace must be replaced prior to

operating the furnace. Clean as follows:

1. Turn heat off. Allow to cool for one hour.

2. Remove the front panel by removing the

five screws.

3. Use pressurized air to remove dust from

the main burner, heat exchanger, and

fan blades.

4. Use a soft, dry cloth to wipe the cabinet.

 Do not use wet cloth or spray cleaners on

the burner.

 The flue should be inspected annually for

blockages or damage.

 Motors are permanently lubricated and do

not need periodic lubrication. Keep fan and

motor free of dust and dirt by cleaning

annually.

 Verify proper operation after servicing.

 When attaching the front panel, do not clip

or pinch any electric cords to prevent electric

shock.

Exterior Care

 Dampen soft cloth with warm water. Wring

water out well and wipe the unit.

 Do not use volatile substances such as

benzene or thinners as they may cause

fading of the paint and deformation of the

resin.

 Prevent dust from accumulating on the

power cord, side covers, and parts

behind the furnace.

 Keep the area around flue terminal free of

snow and ice. The furnace will not

function properly if the intake air or

exhaust is impeded by obstructions.

 Refer to “Flue Terminal Clearances” in

section “4.3.2 Clearances.” The

clearance in Ref. A should be maintained

from any snow accumulation.

CAUTION

To clean the filters, the furnace should be OFF and

cool. Remove the filter and clean it using a soft dry

cloth or vacuum. If the filter is greasy wash with warm

soapy water, rinse, and dry completely.

Do not use the furnace without the filters installed.

6. Maintenance

ABNORMAL

Figure 57

Figure 56

Yellow or

orange flames

Flame Rod

Long, clear, blue,

stable flames

Flame Rod

Air Filters

This beeping will repeat every five minutes. Eventually

the furnace will turn off and display fault code 14 on

the control panel display.

EX38DT Installation and Operation Manual 39

Before making a service call, please check the following:

7. Troubleshooting

AT IGNITION:

Heater does not operate. Is the heater plugged in?

Have the fuses or breaker blown at the fuse box / breaker

panel?

Is there a power failure?

Is the air filter blocked?

Is anything blocking the outlet for the hot air?

Is the flue blocked?

Warm air does not flow when the

burner lights.

The fan is started automatically after a short delay. This is

to allow the heat exchanger to warm up, helping to avoid

cold drafts.

Smoke or strange smells are

produced on the first trial light up

after installation.

This is caused by grease or oil and dust on the heat

exchanger and will stop after a short time.

Sharp clicking noises at ignition, or

when unit cuts down on the

thermostat, or goes out.

This is simply expansion noise from the heat exchanger.

DURING COMBUSTION:

Low, rumbling noise when the

thermostat operates.

This is the sound of the solenoid gas valves opening and

closing.

Unit is not heating room. Is the air filter blocked?

Is the set temperature high enough?

Is the warm air outlet blocked by anything?

Are the doors and windows of the room closed?

Was the appliance correctly sized for the space?

Air filter is blocked or the louvers

are blocked or obstructed.

Allow heater to cool, clean air filter or obstruction, operate

again.

Heater will not re-ignite after

overheating.

Even after unit has cooled down, the heater does not

ignite again. Repair is necessary. Contact a qualified/

authorized service provider.

WHEN THE UNIT IS TURNED OFF:

Convection fan continues to run

after turning OFF.

This is to remove the residual heat from the heat

exchanger. The fan will stop when the heater cools down.

Steam is discharged from the flue

terminal.

High efficiency appliances tend to discharge water vapor

on cold days. This is normal.

Unit cuts off without apparent

reason.

Check whether filters are blocked. Dirty filters will cause

the heater to overheat.

OTHER POINTS:



40 EX38DT Installation and Operation Manual

Issue No ON

Indicator

Burner

Ignition

Abnormal

Combustion

Loss of

Combustion

Gas

Smell

Noisy

Ignition

Takes too

Long to

Warm

Room

Remedy

Not Plugged in

 

Plug in

Power Failure

 



Restart Unit

(Initial

Installation) Air

in Gas Pipe



Purge Air

(Installer)

Gas Filter

Blocked

 



Service Call

Missed Ignition

 

Service Call

Flue Terminal

Obstructed

 



Clear

Obstruction

Flue Manifold

Not Connected

 

Service Call

Louver

Obstructed



Clear

Obstruction

Air Filter

Blocked



Clean Filter

Gas Escape



Service Call

Lock Set



Cancel Lock

Gas Off at

Meter, Tank, or

Valve



Turn Gas On

ON Timer is set



Cancel “ON”

Timer

Additional Troubleshooting Remedies

Table 10: Troubleshooting Remedies

EX38DT Installation and Operation Manual 41

8. Parts

Cut-Away Diagram

Figure 58