Weil-McLain WTGO SERIES 4 OIL-FIRED WATER BOILER WTGO-5R User Manual

Part number 550-142-332/0421

• Installation

• Startup

• Maintenance

• Parts

Boiler Manual

Series 4

Oil-Fired Water Boilers

This manual must only be used by a qualied heating installer/service technician. BEFORE installing, read

all instructions in this manual and all other information shipped with the boiler. Perform steps in the order

given. Failure to comply could result in severe personal injury, death or substantial property damage.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

HOMEOWNER and SERVICE TECHNICIAN — read and follow completely.

The following deﬁned terms are used throughout this manual to bring attention to the presence of hazards

of various risk levels or to important information concerning the life of the product.

Indicates presence of hazards that will cause severe personal injury,

death or substantial property damage.

Indicates presence of hazards that can cause severe personal injury,

death or substantial property damage.

Indicates presence of hazards that will or can cause minor personal

injury or property damage.

Indicates special instructions on installation, operation or

maintenance that are important but not related to personal injury

or property damage.

Hazard deﬁnitions

Homeowner —

Read and follow all information on pages 1 through 7 ONLY.

Service technician —

Read and follow ALL information in the entire manual.

Failure to follow all instructions in proper order can cause severe personal injury, death or

substantial property damage.

Using this manual

When calling or writing about the boiler

Please have boiler model number and series from boiler rating label and Consumer Protection (CP)

number(s) from boiler jacket, burner and controls. On page 30 of this manual is space to list CP number(s).

Packaged boilers: Available only in sizes 3 through 6, are factory assembled, completed with block, collec-

tor hood, jacket, controls and trim. Burner is ordered and shipped separately.

Semi-packaged boilers: Available only in sizes 3 through 6, are shipped with block assembled with collector

hood and jacket installed. Control, trim, and burner are ordered and shipped separately

for ﬁeld assembly.

Knocked-down boilers: Available in sizes 3 through 9, are shipped with block assembled only. All other compo-

nents are ordered and shipped separately for ﬁeld assembly.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

HOMEOWNER and SERVICE TECHNICIAN — read and follow completely.

Contents

Using this manual . . . . . . . . . . . . . . . . 2

Homeowner. . . . . . . . . . . . . . . . . . 2

Service technicians . . . . . . . . . . . . . . . . . . .2

When calling or writing about the boiler . . . . . . . .2

Packaged, Semi-packaged and Knocked-down boilers 2

Hazard deﬁnitions . . . . . . . . . . . . . . . . 2

Contents . . . . . . . . . . . . . . . . . . . . 3

Please read before proceeding . . . . . . . . . 4

Homeowner. . . . . . . . . . . . . . . . . . 4

Service technicians . . . . . . . . . . . . . . . . . . .4

Tips for water systems — . . . . . . . . . . . . . . .4

Saltwater Damage . . . . . . . . . . . . . . . . . . .4

Electrical Damage . . . . . . . . . . . . . . . . . . .4

Frozen Water Damage Hazard . . . . . . . . . . . . .5

Routine maintenance schedule . . . . . . . . . 5

Beginning each heating season . . . . . . . . . . . .5

Daily during heating season . . . . . . . . . . . . . .5

Weekly during heating season . . . . . . . . . . . . .5

End of heating season . . . . . . . . . . . . . . . . .5

Boiler shutdown . . . . . . . . . . . . . . . . . . . .5

Operation . . . . . . . . . . . . . . . . . . . . 6

WTGO (see Figure 1) . . . . . . . . . . . . . . . . . .6

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

Before installing boiler . . . . . . . . . . . . . 8

Installations must comply with . . . . . . . . . . . . .8

Before selecting boiler location . . . . . . . . . . . .8

Provide clearances around boiler (see Figure 2) . . .8

Provide air for combustion and ventilation . . . . . .9

Lay a foundation, if needed . . . . . . . . . . . . . .9

Install boiler — Packaged boilers only. . . . . .10

Place boiler . . . . . . . . . . . . . . . . . . . . . .10

Perform hydrostatic pressure test . . . . . . . . . .10

Install boiler - Semi-packaged & Knocked-down boilers 12

Place boiler . . . . . . . . . . . . . . . . . . . . . .12

Tankless heater, if used. . . . . . . . . . . . . . . . 12

Perform hydrostatic pressure test . . . . . . . . . .14

Install jacket (Knocked-down boilers only) . . . . . 14

Install boiler controls . . . . . . . . . . . . . . . . .14

Install burner — all boilers . . . . . . . . . . .15

Install burner (also refer to instructions

packed with burner) . . . . . . . . . . . . . . . . . 15

Connect breeching . . . . . . . . . . . . . . .16

General chimney requirements. . . . . . . . . . . . 16

Connect breeching . . . . . . . . . . . . . . . . . .16

Connect water piping . . . . . . . . . . . . . .18

General piping information . . . . . . . . . . . . . . 18

Install piping: . . . . . . . . . . . . . . . . . . . . .18

DIAPHRAGM expansion tank (Figure 9) . . . . . . .18

CLOSED expansion tank (Figure 10) . . . . . . . . . 18

To connect WTGO boilers to

indirect-ﬁred water heaters. . . . . . . . . . . . . . 18

Piping MULTIPLE ZONES . . . . . . . . . . . . . . 20

Piping for systems requiring

temperatures below 140°F . . . . . . . . . . . . . .21

Use with refrigeration systems . . . . . . . . . . . . 22

Connect tankless heater piping . . . . . . . . .23

Connect wiring . . . . . . . . . . . . . . . . .24

General wiring requirements . . . . . . . . . . . . .24

Thermostat wiring . . . . . . . . . . . . . . . . . . 24

Zone valve wiring . . . . . . . . . . . . . . . . . . . 24

General wiring . . . . . . . . . . . . . . . . . . . . 24

Burner wiring . . . . . . . . . . . . . . . . . . . . .24

High temperature limit . . . . . . . . . . . . . . . . 24

3-Wire zone valve applications. . . . . . . . . . . . 24

Blocked vent shutoff switch . . . . . . . . . . . . . 27

Connect wiring - vent damper . . . . . . . . . .28

Connect oil piping . . . . . . . . . . . . . . . .28

General oil piping requirements . . . . . . . . . . .28

Start-up . . . . . . . . . . . . . . . . . . . . .29

Fill the system . . . . . . . . . . . . . . . . . . . . 29

When using antifreeze . . . . . . . . . . . . . . . . 29

To place in operation . . . . . . . . . . . . . . . . .29

Burner adjustments. . . . . . . . . . . . . . . . . . 29

Check-out procedure . . . . . . . . . . . . . .30

Check off Steps as completed . . . . . . . . . . . . 30

Installation and service certiﬁcate . . . . . . . . . .30

Annual service check list . . . . . . . . . . . .31

Controls requiring annual service . . . . . . . . . . 31

Detailed service procedures. . . . . . . . . . .32

Cleaning boiler ﬂue ways. . . . . . . . . . . . . . . 32

General description of control operation . . . . . . 32

Handling ceramic ﬁber and ﬁberglass materials 33

Close clearance installation . . . . . . . . . . .34

Close clearance installation . . . . . . . . . . . . . 34

Replacement parts . . . . . . . . . . . . . . .36

Dimensions . . . . . . . . . . . . . . . . . . .41

Ratings . . . . . . . . . . . . . . . . . . . . .42

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

HOMEOWNER and SERVICE TECHNICIAN — read and follow completely.

Please read before proceeding

Follow instructions below to prevent severe personal injury,

death or substantial property damage:

• To avoid electric shock, disconnect electrical supply to burner service

switch and additional external switches before performing service.

• To avoid severe burns, allow boiler to cool before performing service.

• Do not block ﬂow of combustion or ventilation air to boiler.

• Boiler must be connected to a ﬂue with sufﬁcient draft at all times to

assure proper operation.

• Do not use this boiler if any part has been under water. Electrical and

mechanical failures may cause electric shock and ﬁre risks. Immediately

call a qualiﬁed service technician to inspect chimney or vent, boiler

and burner. Have the boiler ﬂue ways cleaned and have the following

replaced:

• all electrical and mechanical controls

• electrical wiring

• oil burner and controls

• insulation and chamber lining

Tips for water systems —

• Check boiler and system piping for leaks. Continual makeup water

will reduce boiler life. Minerals can build up in sections, reducing heat

transfer and causing cast iron to overheat, resulting in section failure.

Failure to maintain recommended pH and repair leaks can

cause section iron corrosion, leading to section failure and

leaks. Do not use petroleum-based sealing or stop-leak com-

pounds in boiler systems. Damage to system components

can result, causing property damage.

• Boiler water pH 7.0 to 8.5 is recommended. For pH conditions outside

7.0 to 8.5 range or unusually hard water areas (above 7 grains hard-

ness), consult local water treatment company.

• When using antifreeze:

 Use antifreeze especially made for hydronic systems. Inhibited

propylene glycol is recommended.

Do not use automotive, ethylene glycol, undiluted or

petroleum-based antifreeze. Severe personal injury, death

or substantial property damage can result.

 50% solution provides protection to about –30°F.

 Local codes may require back-ﬂow preventer or actual disconnect

from city water supply.

 Determine quantity according to system water content. Boiler water

content is listed on back cover of Boiler Manual.

 Percent of solution will affect sizing of heat distribution units,

circulator and expansion tank.

 Follow antifreeze manufacturer’s instructions.

 Do not add cold water to hot boiler. Thermal shock can cause

sections to crack.

Saltwater Damage — The exposure of boiler components to saltwater

can have both immediate and long-term effects. While the immediate

effects of saltwater damage are similar to those of freshwater (shorting

out of electrical components, washing out of critical lubricants, etc.), the

salt and other contaminants left behind can lead to longer term issues

after the water is gone due to the conductive and corrosive nature of

the salt residue. Therefore, Weil-McLain equipment contaminated with

saltwater or polluted water will no longer be covered under warranty

and should be replaced.

Electrical Damage — If any electrical component or wiring came

into contact with water, or was suspected to have come into contact with

water, replace the boiler with a new Weil-McLain boiler.

continued - top of next page

Homeowner —

• For homeowner or person responsible for

simple start-up and routine maintenance of

the system

• Instructions on pages 1 through page 7 must

be followed to assure proper operation of

your boiler. See page 7 for a list of common

problems and possible corrections. In addi-

tion, it is your responsibility to:

• Have boiler and burner installed by a

qualiﬁed installer.

• Have boiler and burner serviced annually

by a qualiﬁed service technician.

• Review and understand start-up and

routine maintenance procedures with

qualiﬁed service technician.

• Perform routine maintenance as de-

scribed on page 5.

Service technician —

• For a qualiﬁed service technician who has

the necessary equipment to check the boiler

and system performance, and is responsible

for start-up and service of boiler and system.

• All instructions in this manual must be

followed to assure proper operation of this

boiler.

• Annually service boiler and burner to assure

proper operation. See page 31 for service

record.

• Review and explain start-up and routine

maintenance procedures with homeowner.

Follow instructions below to pre-

vent severe personal injury, death

or substantial property damage:

• Do not use crankcase drainings or any oil

containing gasoline. See burner manual for

proper fuel oil.

• Do not attempt to start burner when excess

oil has accumulated in combustion cham-

ber, when unit is full of vapor, or when

combustion chamber is very hot.

• Do not start burner unless collector hood,

ﬂue cap, jacket cap, breeching and burner

mounting door are secured in place.

• Never burn garbage or paper in the boiler.

Never leave combustible material around

boiler.

• DO NOT TAMPER WITH UNIT OR CON-

TROLS. Always follow speciﬁc instructions

when starting up boiler or performing rou-

tine maintenance or service.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

HOMEOWNER and SERVICE TECHNICIAN — read and follow completely.

Routine maintenance schedule

Beginning

each heating season

 Call a qualiﬁed service technician to perform annual service.

Daily

during heating season

 Check that boiler area is free from combustible materials, gasoline

and other ﬂammable vapors and liquids.

Weekly

during heating season

 Check for and remove any obstructions to ﬂow of combustion or

ventilation air to boiler.

 Check that breeching is attached between boiler and chimney. If

breeching is loose or damaged, immediately turn off switch on

boiler and call service technician to repair.

 Check for oil leaks in oil piping and around burner. If found, im-

mediately call qualiﬁed service technician to correct situation.

 Check for water leaks in boiler and piping; also check for leaks

around tankless heater plate, if installed. If found, immediately call

service technician to repair.

End

of heating season

 If tankless heater is installed, boiler will continue to operate. Check

for the following:

• All daily and weekly instructions listed on this page must be fol-

lowed.

• Burner motor may have to be oiled. Some motors are permanently

lubricated and do not need additional oil. Check for oiling instruc-

tions on burner or motor.

Boiler

shutdown

 Do not drain boiler unless exposure to freezing temperatures will

occur.

 Always keep manual fuel supply shut off if burner is shut down for

an extended period of time.

• Turn off switch at boiler and any external switch to boiler.

• Close fuel valves.

• Turn off water feed valve.

• Cover burner to protect from dust and dampness.

Frozen Water Damage Hazard

Residences or buildings that are unattended in severely cold weather, boiler system components failures, power outages, or

other electrical system failures could result in frozen plumbing and water damage in a matter of hours. For your protection, take

preventative actions such as having a security system installed that operates during power outages, senses low temperature, and

initiates an effective action. Consult with your boiler contractor or a home security agency.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

HOMEOWNER and SERVICE TECHNICIAN — read and follow completely.

Operation

WTGO (see Figure 1).

1. If burner does not ﬁre, check for:

• Service switch on control or additional switches turned

off.

• Fuses or breaker switch tripped.

• Thermostat set below room temperature.

• Fuel valves turned off.

• Not enough oil in tank to supply burner.

Figure 1 WTGO Boilers

2. Correct problems found in Step #1. If burner does not ﬁre,

press reset button on burner primary control only once.

Repeated presses will deposit oil in combustion chamber.

Burner must never be ﬁred when oil is in combus-

tion chamber. Immediately call qualiﬁed service

technician.

3. If burner still does not ﬁre, call qualiﬁed service technician.

1 Burner disconnect plug

2 Water relief valve

3 Temperature-pressure gauge

4 Circulator

5 Combination limit control,

tankless heater control and

low water cut-off (located in

tankless heater plate)

6 Reset button on burner

primary control

7 Burner primary control

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

HOMEOWNER and SERVICE TECHNICIAN — read and follow completely.

Troubleshooting

Homeowners — The problems and corrections below represent common situations that can occur. There may be

others not listed below. It is important always to contact a qualiﬁed service technician if you have any questions

about the operation of your boiler or system.

Common Problems Common Causes Possible Corrections

Rapid cycling — burner

turns on and off

frequently.

Thermostat installed where

drafts or heat affect reading.

Locate thermostat on inner wall away from heat sources or cool drafts.

Heat anticipator in thermo-

stat adjusted incorrectly.

Adjust heat anticipator to match current draw. Refer to boiler wiring

diagram.

Incorrect limit setting. Have qualiﬁed service technician increase limit setting to decrease

cycling. Maximum setting 220° F.

Need to frequently add

makeup water.

Leaks in boiler or piping. Have qualiﬁed service technician repair leaks at once to avoid constant

use of makeup water.

Popping or percolating

noise heard in boiler.

Mineral deposits in sections

due to constant use of make-

up water, or incorrect pH.

Have qualiﬁed service technician de-lime boiler, repair leaks at once

to avoid constant use of makeup water and check pH (between 7.0

and 8.5).

Black water condition.

Oxygen corrosion due to

leaks in piping. Improper pH.

Have qualiﬁed service technician repair leaks at once to avoid constant

use of makeup water and check pH (between 7.0 and 8.5).

Frequent release of water

through relief valve.

Expansion tank sized too

small or water-logged.

Have qualiﬁed service technician check expansion tank operation.

Metal ﬂakes found in ﬂue

way.

Contaminated combustion

air supply in ﬂue ways.

Remove sources of hydrocarbons in or near boiler area. (Bleaches,

cleaners, chemicals, sprays, fabric softeners, paint remover, etc.)

Condensation of combustion

gases.

Have qualiﬁed service technician check burner nozzle and oil pump

pressure for proper ﬁring rate and check/adjust combustion settings

with an analyzer.

Some radiators or

baseboard units do not

heat or are noisy.

Air in system. Bleed air from system through air vents in radiators or baseboard units.

Low system pressure. Have qualiﬁed service technician check for leaks in boiler or piping

at once.

High limit set too low. Have qualiﬁed service technician adjust limit to higher setting.

Domestic water from

tankless heater is hot

then suddenly turns cold.

Domestic water from

tankless heater is always

lukewarm.

Mineral deposits insulate

internal waterways of heater.

Have qualiﬁed service technician de-lime or replace coil.

Boiler stop-leak compound

has been added to boiler wa-

ter and is insulating outside

of coil.

Have qualiﬁed service technician remove and clean coil and drain,

and ﬂush boiler to remove stop-leak.

Incorrect mixing valve setting

for tankless heater.

Have qualiﬁed service technician adjust mixing valve setting.

Domestic ﬂow rate too high. Have qualiﬁed service technician install ﬂow check valve set to rating

of tankless heater.

Incorrect setting on tankless

heater control.

Have qualiﬁed service technician raise tankless control setting. Adjust

differential on tankless control to lower setting.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Before installing boiler

Top View

Walls

24"

Wall

Left side

Ceiling

Wall

24"

Floor

Installations must comply with

United States

• State and local plumbing, heating and electrical codes.

• National codes where applicable.

• Standard for Controls and Safety Devices for Automatically

Fired Boilers, ANSI/ASME CSD-1, – latest edition, when re-

quired.

• National Electrical Code, ANSI/NFPA 70, – latest edition

and any additional national, state or local codes.

Canada

• Canadian Standards Association, CSA B139, Installation Code for

Oil-Burning Equipment – latest edition.

• CSA C22.1 Canadian Electrical Code Part One – latest edition.

• Applicable local or provincial codes.

Before selecting boiler location

• Check for nearby connections to:

• System water piping.

• Chimney. See page 16. Boiler can be top or back vented.

• Combustion and ventilation air supply. See page 9.

• Oil supply. See page 28 for oil line routing.

• Electrical power.

• Check area around boiler. Remove any combustible

materials, gasoline and other ﬂammable liquids.

Provide clearances around boiler

(see Figure 2)

Jacket cap must be in place on boiler to

avoid requiring an 9" minimum clearance

from back or top of boiler to combustible

material.

• MINIMUM clearances from vent pipe to combustible

material:

• 6 inches — Type “L” double-wall vent*

• 9 inches — Single-wall vent

Flue pipe clearances must take precedence

over jacket clearances.

• Recommended SERVICE clearances:

• 24 inches — Front and top

• 6 inches — Left side, back and right side

• 12 inches — Right side for burner door swing

radius.

• Special close clearances (alcove, closet, under counters,

etc.) — see Close Clearances, page 34.

Homeowner — STOP! The procedures and information on this and following pages are intended only for a

qualiﬁed service technician who has the necessary equipment to inspect and adjust boiler and burner. A homeowner

should never attempt these procedures. The service technician must also read pages 1 through 7 before proceeding.

Failure to keep boiler area clear and free of combustible materials, gasoline and other ﬂammable liquids and vapors

can result in severe personal injury, death or substantial property damage.

Figure 2 Recommended service clearances

A Provide 6" minimum clearance for service, provide 12" mini-

mum clearance for burner door swing.

B Minimum clearance from vent pipe to combustible material:

6" for type “L” double-wall vent, 9" for single-wall vent.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Before installing boiler (continued)

Boiler

Size

Length

inches

Width

inches

Minimum

height

inches

WTGO-3L

22 2

WTGO-3

22 2

WTGO-4

22 2

WTGO-5

22 2

WTGO-6

22 2

WTGO-7

22 2

WTGO-8

22 2

WTGO-9

22 2

Table 1 Boiler foundation sizes

Provide air for combustion and ventilation

Do not install exhaust fan in boiler room.

Adequate combustion and ventilation air:

• Assures proper combustion.

• Reduces risk of severe personal injury or death from possible ﬂue gas

leakage and carbon monoxide emissions.

Older buildings with single-pane windows, minimal weather-stripping and

no vapor barrier often provide enough natural inﬁltration and ventilation

without dedicated openings.

New construction or remodeled buildings are most often built tighter.

Windows and doors are weather-stripped, vapor barriers are used and

openings in walls are caulked. As a result, such tight construction is unlikely

to allow proper natural air inﬁltration and ventilation.

Follow state, provincial or local codes when sizing adequate combustion and

ventilation air openings. In absence of codes, use the following guidelines

when boiler is in a conﬁned room (deﬁned by NFPA 31 as less than 7200

cubic feet per 1 GPH input of all appliances in area. A room 8 ft. high x

33.5 ft. x 33.5 ft. is 7200 cu. ft.):

• Provide two permanent openings — one within 12 inches of ceiling,

one within 12 inches of ﬂoor. Minimum height or length dimension

of each rectangular opening should be at least 3 inches.

• When inside air is used — each opening must freely connect with areas

having adequate inﬁltration from outside. Each opening should be at

least 140 sq. in. per 1 GPH input (1 sq. in. per 1000 Btu input) of all

fuel-burning appliances plus requirements for any equipment that can

pull air from room (including clothes dryer and ﬁreplace).

• When outside air is used — connect each opening directly or by ducts

to the outdoors or to crawl or attic space that freely connects with

outdoors. Size per below:

• Through outside wall or vertical ducts — at least 35 sq. in. per

1 GPH input (1 sq. in. per 4000 Btu input) of all fuel-burning

appliances plus requirements for any equipment that can pull air

from room (including clothes dryer and ﬁreplace).

• Through horizontal ducts — at least 70 sq. in. per 1 GPH boiler

input (1 sq. in. per 2000 Btu input) of all fuel-burning appliances

plus requirements for any equipment that can pull air from room

(including clothes dryer and ﬁreplace).

• Where ducts are used, they should have same cross-sectional area as

free area of openings to which they connect. Compensate for louver,

grille or screen blockage when calculating free air openings. Refer

to their manufacturer’s instructions for details. If unknown, use:

• Wood louvers, which provide 20-25% free air.

• Metal louvers or grilles, which provide 60-75% free air.

Lock louvers in open position or interlock with equipment to prove open

before boiler operation.

Lay a foundation, if needed

Boiler may be installed on non-carpeted combustible

ﬂooring.

For residential garage installation, install boiler so

burner is at least 18 inches above ﬂoor to avoid contact

with gasoline fumes.

A level concrete or masonry foundation is required

when:

• Floor could possibly become ﬂooded.

• Non-level conditions exist.

Solid concrete blocks can be used to create a pad.

Installation instructions:

Packaged boiler — Continued on page 10

Semi-packaged and Knocked-down boiler — Continued on page 12

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Install boiler — Packaged boilers only

Place boiler

1. Remove circulator strapped to pallet.

Circulator will be damaged if not removed before

boiler is lifted from pallet.

2. Remove boiler from pallet.

Do not drop boiler or bump jacket on ﬂoor or

pallet. Damage to boiler can result.

Smaller sized boilers may be top heavy. Use caution

when handling to avoid minor personal injury or

property damage.

3. Boiler is shipped for back ﬂue outlet. To change to top ﬂue

outlet (see Figure 3, page 11):

a. Remove the jacket cap and the 8.00” diameter piece of

insulation that covers the vent opening from the top

jacket panel.

b. Loosen two (2) screws holding ﬂue cap strap to col-

lector hood. Remove strap and ﬂue cap from opening.

Re-tighten screws.

c. Check rope placement inside flue cap.

(Read

under Step #6).

d. Loosen two (2) screws on back ﬂue outlet. Set ﬂue cap on

outlet. Install strap by engaging slots in screws. Tighten

screws. Make sure cap is securely installed.

e. Place the jacket cap insulation disc in the back opening

of the boiler covering the ﬂue cap.

f. Snap jacket cap in back outlet opening.

Jacket cap and insulation disc must be in place on

boiler to avoid requiring an 18” minimum clear-

ance from back of boiler to combustible material.

4. Check level. Shim legs, if needed.

5. Check for secure placement of insulation on target wall,

chamber ﬂoor and burner door.

6. Visually check:

a. Flue collector hood seal.

b. Burner mounting door seal.

Obtain gas-tight seal to prevent possible ﬂue gas

leakage and carbon monoxide emissions, which

can lead to severe personal injury or death.

Perform hydrostatic pressure test

1. Remove relief valve installed in boiler.

2. Install air vent in “N” tapping on top boiler.

3. Plug supply and return tappings.

4. Drain valve is already factory-installed.

5. Fill boiler. Vent all air. Pressure test boiler at 1½ times work-

ing pressure.

Do not leave boiler unattended. Cold water ﬁll can

expand and damage cast iron, resulting in severe

personal injury, death or substantial property dam-

age.

6. Check for maintained gauge pressure for more than 10 min-

utes. Visually check for leaks if gauge pressure drops.

7. Drain boiler. Repair leaks if found.

Do not use petroleum-based sealing compounds

to repair leaks. Damage to system components can

result, causing property damage.

8. Retest boiler after repairing leaks.

9. Remove air vent and plugs. Reinstall relief valve.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Install boiler — Packaged boilers only (continued)

Figure 3 Change from back ﬂue outlet to top ﬂue outlet (optional)

Instructions for Packaged boilers are continued on page 15.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Install boiler –

Semi-packaged and Knocked-down boilers only

Fiberglass wool and ceramic ﬁber materials are

possible cancer hazards. See warning on page 33.

Place boiler

1. Semi-packaged WTGO-3 through 6 — position on site.

Smaller sized boilers may be top heavy. Use caution

when handling to avoid minor personal injury or

property damage.

a. Boiler is shipped for back ﬂue outlet. To change to top

ﬂue outlet (see Figure 4, page 13):

• Remove the jacket cap and the 8.00” diameter piece

of insulation that covers the vent opening from the

top jacket panel.

• Loosen two (2) screws holding ﬂue cap strap to col-

lector hood. Remove strap and ﬂue cap from opening.

Re-tighten screws.

• Check rope placement inside ﬂue cap. (Read

under Step #3.)

• Loosen two (2) screws on back ﬂue outlet. Set ﬂue

cap on outlet. Install strap by engaging slots in screws.

Tighten screws. Make sure cap is securely installed.

• Place the jacket cap insulation disc in the back opening

of the boiler covering the ﬂue cap.

• Snap jacket cap in back outlet opening.

Jacket cap and insulation disc must be in place on

boiler to avoid requiring an 18” minimum clearance

from back of boiler to combustible material.

2. Knocked-down WTGO-7, 8 & 9 — split the assembled block

for easier handling (see Figure 4, page 13):

a. Open burner mounting door and, using utility knife, slit

ﬂoor insulation at joint to be separated.

b. Remove 5½" draw rod and the longest draw rod from each

side. Pull block apart. Save draw rods, nuts, washers and

sealing rings for reassembly.

c. Move divided block to location.

d. Clean port openings with clean rag.

Do not use petroleum-based compounds to clean

openings. Damage to system components can result,

causing property damage.

e. Place rings in port openings. If ring slips out of groove,

stretch ring gently for several seconds, then place in groove.

f. Position sections so aligning lugs ﬁt into sockets of next

section. Make sure sealing rope is in good condition and

in position.

g. Oil threads on draw rods. Install washer and nut on end

to be tightened. Use nut only on other end.

h. With wrench at washer/nut end, uniformly tighten nuts

starting with 5½" rod at large port, 5½" rod at small port,

bottom long rod and ﬁnally top long rod.

i. Torque on both 5½" rods and bottom long rod should

be 50–60 ft-lbs; long top rod should be 20–25 ft-lbs. Do

not back-off nuts.

j. Metal-to-metal contact should be made around port

openings. If gap does exist, it should be less than .020”.

Check with feeler gauge.

k. If gap around port openings exceeds .020”, check for dirt

on port openings, sockets or misaligned lugs. If correc-

tions are made and gap still exists, contact our Technical

Services group for assistance before continuing instal-

lation.

3. Knocked-down WTGO-3 through 9 — install ﬂue collector

hood (see Figure 4, page 13):

Obtain gas-tight seal to prevent possible ﬂue gas

leakage and carbon monoxide emissions, leading

to severe personal injury or death.

a. Thread Tinnerman clip on screw so that clip ﬁts snugly

in notch of hold-down lug. Screw must not turn.

b. Remove paper on sealing rope. Starting at back section

near ﬂue collar, position sealing rope around top of block

with adhesive side to sections. Do not stretch rope. Make

sure rope ends meet. Trim excess rope.

c. Position ﬂue collector hood on top of boiler sections

and over screws and clips as shown in Figure 4, page 13.

d. Install washers and nuts. Tighten nuts until collector hood

makes contact with Tinnerman clip.

e. Back ﬂue outlet boiler — Position ﬂue cap and strap over

opening in ﬂue collector hood. Make sure rope in cap is

in place and in good condition. Tighten strap to hood

with screws provided.

Top ﬂue outlet boiler — Position ﬂue cap and strap over

opening in back section.

f. Make sure rope in cap is in place and in good condition.

Tighten strap to boiler with screws provided in section.

Install remaining screws in holes in ﬂue collector hood.

Tankless heater, if used

1. Remove tankless heater cover plate and gasket.

2. Install new gasket and tankless heater over studs around open-

ing. Secure with 3/8" nuts, tightening until metal-to-metal

contact is made (20–25 ft-lbs).

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Sealing

rope in

groove

inside cap

Flue

cap

Flue cap

strap

Flue

collector

hood

Sealing

rope with

adhesive

tape

Separate

block here

for easier

handling

Nut

Washer

Tinnerman

clip

Screw

Hold-down

lug

Install boiler –

Semi-packaged and Knocked-down boilers only (continued)

Figure 4 Change from back ﬂue outlet to top ﬂue outlet (optional)

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Location Size Function

B1 1½" Return piping

B2 1½" Alternate return piping for

WTGO

C 1½" Supply piping

E3 ¼" Pressure-temperature

gauge

H ¾" Drain valve

L ¾" High limit control

(in tankless heater cover

plate)

N ½" Air vent or expansion tank

piping

R1 ¾" Relief valve

Front section

Back section

Install boiler –

Semi-packaged and Knocked-down boilers only (continued)

Perform hydrostatic pressure test

1. Refer to Control Tapping Table 2 and Figure 5 to install:

a. Boiler drain.

b. Water pressure gauge (test only). Be sure gauge can

handle test pressure.

c. Air vent in upper “N” tapping.

d. Plugs in remaining tappings.

2. Fill boiler. Vent all air. Pressure test boiler at 1½ times work-

ing pressure. For boilers split and reassembled, test between

75 and 85 psig.

Do not leave boiler unattended. Cold water ﬁll

could expand and damage cast iron, resulting in

severe personal injury, death or substantial prop-

erty damage.

3. Check for maintained gauge pressure for more than 10 min-

utes. Visually check for leaks if gauge pressure drops.

4. Drain boiler. Repair leaks if found.

Do not use petroleum-based compounds to repair

leaks. Damage to system components can result,

causing property damage.

5. Re-test boiler after repairing leaks.

6. Remove pressure gauge, air vent and plugs from tappings

used for controls.

7. Visually check:

a. Sealing rope placement

b. Metal-to-metal contact around port openings.

c. Flue collector hood seal.

d. Burner mounting door seal.

Obtain gas-tight seal to prevent possible ﬂue gas

leakage and carbon monoxide emissions, which

can lead to severe personal injury or death.

Install jacket

(required on sizes 7 through 9 only)

Before installing jacket, remove burner mounting door. See jacket

instructions for details.

Install boiler controls

See Control tapping (Table 2), Figure 5 and Figure 6 to install

controls.

1. Install tankless heater control if tankless heater is used. If

not furnished, use operating control with maximum 10°F

differential.

2. Install limit control. If not furnished, use high limit with

maximum 220°F setting.

3. Afﬁx Consumer Protection (CP) number label(s) on jacket

front panel.

Table 2 Control tappings Figure 5 Control tapping locations

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Relief

valve

Water

pressure-temperature

gauge

Combination

Limit control

and low water

cut-off

Drain valve

Circulator

Figure 6 Water boiler controls

Install burner

(also refer to instructions packed with burner)

Use only burners speciﬁed for use on Weil-

McLain oil boilers. Contact individual

burner manufacturers for proper burner

selections.

For burners with OEM welded ﬂanges:

1. Secure mounting ﬂange and gasket to burner

mounting door. Use three (3) bolts provided.

2. Open door to verify secure placement of insulation

on target wall, chamber ﬂoor and burner mounting

door.

3. Securely close door and tighten nut.

For burners without OEM welded ﬂanges:

1. Secure universal mounting ﬂange and gasket to burner mounting

door. Use three (3) bolts provided.

2. Secure burner on ﬂange with three (3) bolts.

3. Position burner so end of air tube is level to 1½-degree tilt down

toward chamber. Open door to verify burner position. End of air

tube should be ﬂush to ¼" recessed from inside wall of burner door

refractory. Check for secure placement of insulation on target wall,

chamber ﬂoor and burner mounting door.

4. Securely close door and tighten nut.

Install burner — all boilers

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Connect breeching

Table 3 Minimum chimney sizes

Boiler

Size

Minimum

breeching

diameter

(Note 3)

Minimum

AHRI

chimney size

Minimum

chimney

height

Rect. Round

WTGO-3

8" x 8"

(Note 1) 6" 15'

WTGO-4

WTGO-5

8" x 8"

(Note 1) 7" 15'

WTGO-6

WTGO-7

WTGO-8

8" x 12"

(Note 2)

7" 20'

WTGO-9

NOTE:

1. 6¾" x 6¾" inside liner.

2. 6½" x 10½" inside liner.

3. Flue collar on boiler is 7" diameter

General chimney requirements

• Designed for natural draft ﬁring. Connect boiler to vertical chim-

ney.

Insufﬁcient draft can cause ﬂue gas leakage and carbon

monoxide emissions, which will lead to severe personal

injury or death.

• Use vent material approved by local codes for oil-ﬁred burners. In

their absence, refer to:

• NFPA 31 – latest edition, Installation of Oil-Burning Equipment.

• NFPA 211 – latest edition, Standard for Chimneys, Fireplaces,

Vents and Solid Fuel Burning Appliances.

• In Canada, refer to CSA B139, Installation Code for Oil-

Burning Equipment – latest edition.

• NFPA 211 requires chimney to be lined before connected to boiler.

Inspect existing chimney before installing new boiler.

Failure to do any of the following will result in severe

personal injury or death:

• Clean chimney, including removal of blockage.

• Repair or replace damaged pipe or liner.

• Repair mortar and joints.

To prevent downdrafts, extend chimney at least 3 feet above highest

point where it passes through roof and 2 feet higher than any portion

of building within 10 feet. Increase chimney cross-sectional area and

height at least 4% per 1,000 feet above sea level.

• Minimum clearances from vent pipe to combustible material:

Type “L” double-wall vent — 6 inches

Single-wall vent — 9 inches

• Minimum chimney sizes should be used.

Oversized chimneys, outside masonry chimneys and/or

de-rated inputs can result in condensation in chimney.

Connect breeching

Long horizontal breechings, excessive numbers of tees

and elbows or other obstructions restricting combustion

gas ﬂow can result in possibility of condensation, ﬂue gas

leakage and carbon monoxide emissions, which can lead

to severe personal injury or death.

1. Install two (2) ﬂue pipe brackets.

2. Connect full-sized breeching when possible. See Minimum Chim-

ney Size Table.

• Back outlet — see Figures 7 and 9, page 17.

• Top outlet — see Figures 8 and 10, page 17.

Connection must be made above bottom of chimney to avoid blockage.

Breeching must not enter chimney far enough to cause obstruction.

Use thimble or slip joint where breeching enters chimney to allow

removal for cleaning.

3. When burner and boiler are properly installed, draft

over ﬁre will be approximately -0.01" to -0.02" W.C.

Install barometric control in breeching, per control

manufacturer’s instructions, when excess draft needs

to be relieved or to comply with applicable codes and

regulations. Use draft gauge to adjust proper opening.

4. An induced draft fan for the chimney may be neces-

sary if:

• Excessive resistance to ﬂow of combustion gases

can be expected.

• Cross-sectional area of chimney is smaller than

minimum recommended.

• Chimney height is less than recommended.

Seal all vent joints. Interlock burner with fan

operation.

5. Boiler models ending in “D”, such as WTGO-3D, require

the installation of the Field Controls OVD-7 automatic

damper kit, Weil-McLain part number 381-800-515.

Refer to Figures 7 and 8, page 17.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Connect breeching (continued)

Figure 7 Back Outlet Breeching Vent Damper for

models which require a vent damper.

Figure 8 Top Outlet Breeching for models which require

a vent damper.

Figure 9 Back outlet breeching connection for models

which do not require a vent damper.

Figure 10 Top outlet breeching connection for models

which do not require a vent damper.

Typical location for

barometric control

(Also see control

manufacturer’s

instructions)

Flue pipe

bracket

(One on each

side of pipe)

Typical location for

barometric control

(Also see control

manufacturer’s

instructions)

Flue pipe bracket

(One on each

side of pipe)

0251-056_OVD

OVD Damper

(Required)

BVSS

(WMO-1)

(Integrated with damper)

BVSS must be installed

upstream of the barometric

damper.

Typical location for

barometric control

(Also see control

manufacturer’s

instructions)

Flue pipe

bracket

(One on each

side of pipe)

0250-056_OVD

OVD

Damper

(Required)

Flue pipe

bracket

(One on each

side of pipe)

Typical location for

barometric control

(Also see control

manufacturer’s

instructions)

BVSS

(WMO-1)

(Integrated with damper)

BVSS must be installed

upstream of the

barometric damper.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Connect water piping

Table 4 Water piping sizes

General piping information

• All Packaged WTGO boilers are shipped with an installed combination

temperature limit control/low water cut-off.

• If installation is to comply with ASME, an additional high temperature

limit is needed. If installation is to comply with Canadian requirements,

an additional high temperature limit maybe needed. Consult local

inspector. Install control in supply piping between boiler and isolation

valve. Set control to a minimum of 20°F above set point of combination

control. Maximum allowable set point is 220°F. Wire control as shown

on wiring diagram.

• Use back ﬂow check valve in cold water supply as required by local codes.

Install piping:

• See Figure 11 or Figure 12, page 19 and Water Piping Size Table 4 for

near-boiler piping and single-zone piping. See page 20 to complete

multiple-zone piping or page 21 to complete piping for systems oper-

ating below 140°F.

• For multiple-boiler piping, contact Weil-McLain Technical Services

for assistance, if required.

• Install relief valve vertically in “R1” tapping on front of boiler. See

Figure 11 or Figure 12 and also refer to tag attached to relief valve for

manufacturer’s instructions.

Pipe relief valve discharge line near ﬂoor close to ﬂoor drain

to eliminate potential of severe burns. Do not pipe to any

area where freezing could occur. Do not plug, valve or place

any obstruction in discharge line.

DIAPHRAGM expansion tank

(Figure 11, page 19)

• Make sure expansion tank size will handle boiler and system water

volume and temperature. Tank must be located near boiler before inlet

to circulator. See tank manufacturer’s instructions for details.

Undersized expansion tanks cause system water to be lost

from relief valve and makeup water added through ﬁll valve.

Eventual section failure can result.

• Install automatic air vent in “N” tapping as shown in Figure 11, page 19.

CLOSED expansion tank

(Figure 12, page 19)

• Ensure expansion tank size will handle boiler and system water volume

and temperature.

• Undersized expansion tanks cause system water to be lost from relief

valve and makeup water added through ﬁll valve. Eventual section

failure can result.

• Connect tank from “N” tapping shown in Fig-

ure 12, page 19 to expansion tank. Use ½" NPT

piping. Pitch any horizontal piping up towards

tank 1 inch per 5 feet of piping.

To connect WTGO boilers to

indirect-ﬁred water heaters

• Install and wire per water heater manual provided

with water heater.

• If boiler has a tankless heater installed:

• Remove tankless heater and install cover plate.

• Leave tankless heater installed. Drain coil and re-

move piping. Do not plug holes in tankless heater

front plate.

Boiler

Size

To system From system

WTGO-3 1¼" 1¼"

WTGO-4 1¼" 1¼"

WTGO-5 1½" 1½"

WTGO-6 1½" 1½"

WTGO-7 1½" 1½"

WTGO-8 2" 2"

WTGO-9 2" 2"

* All piping sizes based on 20°F

temperature rise through boiler.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Connect water piping (continued)

Figure 11 Piping with DIAPHRAGM expansion tank

Figure 12 Piping with CLOSED expansion tank

Isolation

valve

From

system

Isolation valve

Cold water ﬁll

To system

“C” tapping

“N” tapping

“B1” tapping

Relief valve

Circulator

Closed type expansion

tank

Circulator

(Alternate circulator location)

Isolation valve

Circulator

Automatic

air vent

Relief valve

To diaphragm

expansion tank

and ﬁttings

From

system

To system

“C” tapping

“N” tapping

Isolation

valve

Cold water

ﬁll

“B1”

tapping

Circulator

(Alternate circulator

location)

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Zone 2

Zone 1

Connect water piping (continued)

Zone 2

Zone 1

Piping MULTIPLE ZONES

Follow instructions on page 18 and page 19 to install

piping near boiler.

See Figure 13 or Figure 14 to complete installation.

Zoning with circulators:

1. Size each circulator to individual circuit require-

ments.

2. Install balancing valves to adjust ﬂow to distribute

heat to all zones.

3. Separate relay is required for each circulator.

Zoning with zone valves:

1. Install balancing valves to adjust ﬂow to distribute

heat to all zones.

2. Separate transformer is required to power zone

valves. Refer to manufacturers installation instruc-

tions for wiring or contact our Technical Services

group for assistance.

3. Pressure bypass valve recommended on zone valve

systems to prevent excessive ﬂow in a single zone

or water hammer when valves close.

Legend

1 Isolation valve

2 Flow control valve

3 Circulator

4 Zone valve

5 Drain valve

Figure 13 Multiple zoning with CIRCULATORS

Figure 14 Multiple zoning with ZONE VALVES

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Connect water piping (continued)

Figure 15 Piping with CIRCULATORS

Figure 16 Piping with ZONE VALVES

Piping for systems requiring

temperatures below 140°F

In most systems, this type of piping is not required. If

system water temperature requirements are less than

140°F, such as radiant panels or converted gravity sys-

tems, use piping as shown in Figure 15 or Figure 16. If

system piping is plastic without an oxygen barrier, a

heat exchanger must be used.

Legend

1 Isolation valve

2 Flow control valve

3 Circulator

4 System temperature

gauge

5 Zone valve

6 Drain valve

7 System temperature

valves

Adjust valves so that:

- the temperature at

gauge 8 is at least 140°F

- the temperature at

gauge 9 is at least 160°F

8 Blend temperature

gauge

9 Boiler temperature

gauge

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Use with refrigeration systems

• Install boiler so that chilled medium is piped in

parallel with heating boiler. Use appropriate valves

to prevent chilled medium from entering boiler.

Consult AHRI Installation and Piping Guides.

• If boiler is connected to heating coils located in

air handling units where they can be exposed to

refrigerated air, use ﬂow control valves or other

automatic means to prevent gravity circulation

during cooling cycle.

Figure 17 Use with refrigeration system

Connect water piping (continued)

Supply

Circ.

Chiller

Strainer

Exp. tank

1 Isolation valves 2 Balancing valve

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Connect tankless heater piping

Limit Control with

Tankless Control

Automatic Mixing

Valve

Flow Regulating

Valve

Cold Water

Supply

12" min.

Cold

Hot

Mixed

Figure 18 Tankless heater pipingTable 5 Tankless heater ratings

NSF/ANSI 372

Boiler

Size

Heater

number

Intermittent

draw

ratings

(gpm)*

Inlet

and

outlet

tapping

sizes

WTGO-3 WT-14 3.25 ½"

WTGO-4 WT-14 3.75 ½"

WTGO-5 WT-14 4.00 ½"

WTGO-6 WT-14 4.25 ½"

WTGO-7 WT-20 5.50 ½"

WTGO-8 WT-20 5.75 ½"

WTGO-9 WT-20 6.00 ½"

* Gallons of water per minute heated from 40°F

to 140°F with 200°F boiler water temperature.

Tested in accordance with AHRI Testing and

Rating Standard for Indirect Tankless Water

Heaters Tested with Boilers.

Studies have indicated that dangerous bacteria can form

in potable water distribution systems if certain minimum

water temperatures are not maintained. Contact local

health department for more information.

To pipe tankless heater:

1. Size piping no smaller than tankless heater inlet and outlet.

2. Following controls (furnished by others) must be installed:

a. Automatic mixing valve. - See Figure 18.

b. Flow regulating valve. Size according to intermittent draw of tankless

heater. See Table 5 Follow valve manufacturer’s instructions to install.

3. Additional anti-scald devices may be installed at each hot water faucet,

bath and shower outlet.

4. In hard water areas, soften cold domestic supply water to heaters to

prevent lime build-up

These single wall heat exchangers comply with National Standard

Plumbing Code provided that:

• Boiler water (including additives) is practically non-toxic, having a

toxicity rating or class of 1, as listed in Clinical Toxicology of Com-

mercial Products.

• Boiler water pressure is limited to max. 30 psig by approved water

relief valve.

Hot Water Can Scald!

• Consumer Product Safety Commission and

some states recommend domestic hot water

temperature of 130°F or less.

• When installing an automatic mixing valve,

selection and installation must comply with

valve manufacturer’s recommendations and

instructions.

• Water heated to a temperature suitable for

clothes washing, dish washing and other sanitiz-

ing needs will scald and cause injury.

• Children, elderly, inﬁrm or physically handi-

capped persons are more likely to be injured

by hot water. Never leave them unattended in

or near a bathtub, shower or sink. Never allow

small children to use a hot water faucet or draw

their own bath. If anyone using hot water in the

building ﬁts this description, or if state laws or

local codes require certain water temperatures

at hot water faucets, take special precautions:

• Install automatic mixing valve set according

to those standards.

• Use lowest practical temperature setting.

• Check water temperature immediately after

ﬁrst heating cycle and after any adjustment.

Tankless water heaters for WTGO boilers have

been tested and certiﬁed by the CSA Group

(certiﬁcate # 2552127).

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

DO NOT connect directly from 3-wire

zone valves to the T-T terminals on

the boiler

. When using 3-wire zone valves,

install an isolation relay. Connect the zone

valve end switch wires to the isolation relay

coil. Connect the isolation relay contact across

the boiler T-T terminals. Failure to comply

can result in damage to boiler components

or cause unreliable operation, resulting in

possible severe property damage.

General wiring requirements

Electric shock hazard – Can cause severe personal

injury or death if power source, including service

switch on boiler, is not disconnected before install-

ing or servicing.

• Installations must follow these codes:

• National Electrical Code, ANSI/NFPA 70, – latest edition

and any additional national, state or local codes.

• In Canada, CSA C22.1 Canadian Electrical Code Part 1,

– latest edition and any local codes.

• Wiring must be NEC Class 1. If original wire as supplied

with boiler must be replaced, type 105°C wire or equivalent

must be used. Supply wiring to boiler and additional control

wiring must be 14 gauge or heavier.

• Provide electrical ground at boiler as required by codes.

Thermostat wiring

• Install thermostat on inside wall away from inﬂuences of

drafts, hot or cold water pipes, lighting ﬁxtures, television,

sun rays or ﬁreplaces.

• Follow instructions with thermostat. If it has a heat an-

ticipator, set heat anticipator in thermostat to match power

requirements of equipment connected to it. Boiler wiring

diagrams give setting for standard equipment.

Zone Valve Wiring

4- wire zone valves may be connected directly to the boiler

control.

General wiring

• Packaged boilers have harnesses furnished.

• For Semi-packaged and Knocked-down boilers, trim kits are

furnished with burner and limit harnesses integrated with

Hydrolevel control.

• All ﬁeld-provided high voltage wiring must be sheathed in

ﬂexible metal conduit.

• Connect incoming line voltage “HOT” wire to service switch,

and neutral wire to white wire. Field-install equipment

ground wire to green wire with wire nut inside Hydrolevel

control.

• Service switch is integrated into the Hydrolevel control.

• Some local codes may require an emergency shut-off switch

installed at a location away from boiler. Follow local codes.

Burner wiring

• Burner harness incorporates a disconnect plug, providing a

convenient way to disconnect wiring when burner mounting

door is opened.

• All Packaged boilers have a power disconnect plug installed

on burner.

• On Semi-packaged and Knocked-down boilers, mount the

plug (P/N 591-391-850, included in water trim carton) on

the burner housing as shown in Figure 19, page 25. For Carlin

burners, screw burner plug into threaded conduit coupling,

then mount this assembly to the burner housing using the

chase nipple.

High temperature limit

• To comply with ASME, UL 726 or Canadian requirements,

an additional high temperature limit is needed.

• Install the secondary control in the supply piping between

boiler and isolation valve.

• Set the control to a minimum of 20˚F above the set point of

the combination control.

• The maximum allowable set point is 220˚F.

• Wire the control as shown on page 26.

Connect wiring

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Limit control

Service

switch on

control

Burner

wiring

harness

Burner

disconnect

plug

Figure 19 Boiler wiring for forced hot water

Connect wiring (continued)

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Figure 20 Wiring diagram

Connect wiring (continued)

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

120 vac

ﬁeld wiring

Low voltage

ﬁeld wiring

120 vac

factory wiring

Low voltage

factory wiring

Connect wiring — blocked vent shutoff switch option

Figure 21 Blocked vent shutoff switch installation Figure 22 BVSS wiring diagram

Blocked vent shutoff switch

Canada, blocked vent shutoff switch kit

(see parts list page 36) must be installed.

See Figure 21.

When using the OVD damper kit, the

BVSS is required, and is integrated into

the damper harness wiring.

When using the BVSS without the OVD

damper, the BVSS is wired directly to the

Combination limit control as follows.

The wiring diagram in Figure 22 shows

boiler wiring only up to the burner

disconnect. For additional information,

refer to manufacturer’s instructions.

Electric shock hazard – Turn off electrical

power supply at service entrance panel

before making any electrical connections

to avoid possible electric shock hazard.

Failure to do so can cause severe personal

injury or death.

After installing BVSS switch, proceed as follows

1. Disconnect power.

2. Install Shutoff Switch (BVSS) Wiring Harness (P/N 591-391-942, which

is included in BVSS kit P/N 591-624-650) as follows:

a. Remove cover from BVSS Box.

b. Install straight ﬁtting end of the harness on the BVSS Box. Install

elbow (90º) end ﬁtting on the right side of the Hydrolevel control.

c. Install both the fork ends to the screw terminals on the BVSS Switch

as per the wiring diagram, (see Figure 22).

d. Replace BVSS box cover.

e. Locate Combination Control, remove cover, and disconnect red

wire from “B1” terminal.

f. If red wire from Step “e” has uninsulated female end, replace it

with insulated female end as supplied in kit.

g. Connect female end of Shutoff Switch BVSS Harness (blue wire)

to “B1” terminal.

h. Connect male end of Shutoff Switch BVSS Harness to the red wire

removed in Step “e”.

i. Replace Combination Control Cover.

3. Turn on power and verify safe operation of the appliance.

4. Restore boiler to normal operation.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Flare ﬁtting

See local codes for appropriate

arrangement and piping of ﬁlter

control valves, etc., back to oil tank.

General oil piping requirements

• Location and installation of oil tanks, oil piping and

burners must follow:

• NFPA 31 - latest edition, Standard for the Installation

of Oil-Burning Equipment.

• In Canada, CSA B139, Installation of Oil-Burning

Equipment.

• Local codes and regulations.

• Information provided with burner and fuel pump.

• If any part of fuel oil tank is above level of burner, instal-

lation of an anti-siphon device is highly recommended

to be used to prevent ﬂow of oil in case of oil line break.

• Support oil lines as required by codes.

• Make tank connections with swing joints or copper tubing

to prevent breaking in case the tank settles. Make swing

joints so they will tighten as tank settles. Non-hardening

pipe joint compounds should be used on all threads.

Do not use Teﬂon tape as an oil pipe sealant. It

can cause valves to fail, creating hazards. Do not

use compression ﬁttings.

• Underground pipe must be run in a casing to prevent oil

leaking into ground or under ﬂoor. Check local codes for

information.

Oil piping connection at burner

See Figure 24 for recommended connection at burner, al-

lowing burner mounting door to swing open completely for

servicing.

Figure 23 OVD Vent damper wiring diagram

1. WTGO Boiler models ending in “D”, such as WTGO-3D,

require the installation of the Field Controls OVD-7 damper,

Weil-McLain part number 381-800-515.

2. When installing the boiler, wire all controls from vent damper

and thermal switch in accordance with the OVD damper

manual and the following wire diagrams.

3. Connect damper wires to the boiler as follows:

a. Remove black wire (burner disconnect harness) from

the B1 terminal, and connect that wire to the Yellow

wire from damper, using a wire nut.

b. Connect the orange wire from the damper to the B1

screw terminal.

c. Connect the black wire from the damper to the L1

screw terminal.

d. Connect the white wire from the damper to the L2

screw terminal.

e. Connect the green wire from the damper to ground.

Connect oil piping

Connect wiring - vent

damper

Figure 24 Recommended oil piping connection to

burner

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Start-up

Fill the system

1. Close manual and automatic air vents and boiler

drain cock.

2. Fill to correct system pressure. Correct pressure will

vary with each installation. Normal cold water ﬁll

pressure for residential systems is 12 psig. Boiler

water pH 7.0 to 8.5 is recommended.

Failure to maintain recommended pH

level can cause section failure and leaks.

3. Open automatic air vent one turn.

4. Open other vents.

a. Starting on the lowest ﬂoor, open air vents one

at a time until water squirts out. Close vent.

b. Repeat with remaining vents.

5. Reﬁll to correct pressure.

When using antifreeze

Do not use automotive, ethylene glycol,

undiluted or petroleum-based antifreeze.

Severe personal injury, death or substan-

tial property damage can result.

• Use antifreeze especially made for hydronic systems.

Inhibited propylene glycol is recommended.

• 50% solution provides protection to about -30°F.

Do not exceed 50% mixture.

• Local codes may require back-ﬂow preventer or

actual disconnect from city water supply.

• Determine quantity according to system water con-

tent. Boiler water content is listed on back cover of

manual. Percent of solution will affect sizing of heat

distribution units, circulator and expansion tank.

• Follow antifreeze manufacturer’s instructions.

• Do not add cold water to hot boiler. Thermal shock

can cause sections to crack.

To place in operation

1. Verify boiler is ﬁlled with water.

2. Open burner mounting door and verify rear tar-

get wall, ﬂoor and burner door insulations are in

proper position.

3. Verify burner mounting door is closed tightly and

burner wiring harness is connected to Hydrolevel

control.

Factory burner adjustment and settings may not be

suitable for speciﬁc job conditions. See “Burner adjust-

ments”, below.

A burner nozzle change may be required -

refer to the burner instructions or boiler’s

rating label for correct nozzle selection

Make final burner adjustments using

combustion test equipment to assure

proper operation. Do not fire boiler

without water. Sections will overheat,

damaging boiler and resulting in sub-

stantial property damage.

4. Vent air from system. Repeat Steps 4 and 5 under

“Fill the system.” Air in system can interfere with

water circulation and cause improper heat distri-

bution.

5. Check boiler and system piping for leaks. See “Tips

for water systems” on page 4.

6. Inspect breeching and venting for proper operation.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Date Installed: ____________________________

Boiler Model Number: _______ Series: ____________

Consumer Protection (CP) Number(s): _________

Measured Btu or GPH Input: ________________



Installation instructions have been followed.



Check-out procedure has been performed.



Above information is certiﬁed to be correct.



Information received and left with owner/

maintenance person.

Installation and service certiﬁcate

Installer: ________________________________________________________________________________________________

(Company) (Address) (Phone)

_________________________________________

(Installer’s Signature)

Installation and service certiﬁcate

Check off Steps as completed



Boiler and heat distribution units ﬁlled with water?



Automatic air vent, if used, opened one full turn?



Air purged from system? Piping checked for leaks?



Air purged from oil piping? Piping checked for leaks?



Flue cap in place and tightened? Burner door closed, sealed

and nut tight? Burner plugged in and service switch on?

Obtain gas-tight seal to prevent possible ﬂue gas

leakage and carbon monoxide emissions, leading

to severe personal injury or death.



Proper draft and burner ﬂame? Final adjustment made with

combustion test equipment?



Test limit control: While burner is operating, move indica-

tor on limit control below actual boiler water temperature.

Burner should go off while circulator continues to operate.

Raise setting on limit control above water temperature and

burner should re-ignite.



Test additional ﬁeld-installed controls: If boiler has a low

water cutoff, additional high limit or other controls, test for

operation as outlined by manufacturer. Burner should be

operating and should go off when controls are tested. When

controls are restored, burner should re-ignite.



Limit control set to system temperature requirements (max.

220°F)?



For multiple zones, ﬂow adjusted to distribute heat in all

zones?



Thermostat heat anticipator setting (if available) set properly?

Refer to “Connect wiring, ” page 24.



Boiler cycled with thermostat? Raise to highest setting and

verify boiler goes through normal start-up cycle. Lower to

lowest setting and verify boiler goes off.



Observed several operating cycles for proper operation?



Set room thermostat(s) to desired room temperature?



Completed Installation and Service Certiﬁcate below?



Reviewed pages 1–7 with owner or maintenance person and

instructed person to keep for future reference?



Returned all instructions provided with boiler to its envelope

and placed with boiler for future reference?

Check-out procedure

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Annual service check list

Annual Service Call

Checklist

(follow in order listed below)

Dates Comments

Check that boiler area is free from combus-

tible materials, gasoline and other ﬂam-

mable vapors and liquids.

Check for and remove any obstruction

to combustion and ventilation air ﬂow to

boiler.

Check breeching and chimney or vent for

obstructions, damage, etc. Repair or replace

as necessary.

Clean boiler ﬂue ways. See page 32.

Perform service on relief valve and circula-

tor. See below.

Check boiler and piping for leaks and repair

if found. Check for leaks at tankless heater

plate. Tighten nuts only if leaks are found

(for WTGO torque to 20-25 ft.lbs.).

Inspect and adjust burner. See burner

manual and:

• change nozzle.

• check ignition electrode settings.

• clean blower housing and wheel.

• make sure blower wheel turns freely.

• oil burner motor if required.

• clean air inlet.

• clean or change fuel ﬁlter and strainer.

Make sure boiler is ﬁlled with water.

Start unit and verify combustion settings

with combustion test equipment.

See page 34.

Verify operation of all controls on boiler.

See page 30.

Any parts of the boiler furnished by Weil-McLain must be replaced by parts listed in Weil-McLain Boiler and Repair Parts Book.

Controls requiring annual service

Water Relief Valve

Check operation of water relief valve.

Follow instructions on label fastened to

relief valve.

Scald potential. Do not check

operation of relief valve un-

less discharge piping has

been installed according to

Boiler Manual. If piping is

not in place, a qualiﬁed ser-

vice technician must prop-

erly install piping.

Circulator

Follow oil-lubricating instructions on cir-

culator. Over-oiling will damage circulator.

Water-lubricated circulators do not need

oiling.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Detailed service procedures

Cleaning boiler ﬂue ways

Make sure all electrical connections to

boiler are turned off and wait until boiler

is warm, not hot, before cleaning. Failure

to do so will result in severe personal

injury, death or substantial property

damage.

1. Top ﬂue boilers — remove breeching and jacket

top panel. Rear ﬂue boilers — remove jacket top

panel.

2. Remove ﬂue collector hood, saving hardware for

reassembly.

3. Shut off oil valves. Arrange drip pans under the

areas of oil piping that will be disconnected. Dis-

connect oil line at burner so that you can swing

open the door completely.

4. Line combustion chamber ﬂoor with newspaper to

catch any soot that will be loosened in the cleaning

process.

5. Starting at the top of the boiler, use a wire ﬂue brush

to thoroughly clean between all pins at all angles. Be

careful not to damage side walls of rear refractory.

6. Move to the bottom of the ﬂue ways and clean up

between the sections to reach pins left uncleaned

in Step #5.

7. Once the ﬂue ways are cleaned, carefully remove the

paper from the ﬂoor of the combustion chamber.

8. Verify sealing rope around ﬂue area is intact. Visually

check condition and position of insulation in combus-

Figure 25 Thoroughly clean ﬂue ways between

all pins at all angles. Start on top of

boiler, ﬁnish from the bottom.

tion chamber ﬂoor, and the refractories at the rear of boiler and in the burner

mounting door. Replace any parts as necessary.

9. Close burner mounting door and tighten nut securely. Place ﬂue col-

lector hood on top of boiler. Secure with hardware from Step #2.

Maintain a gas-tight seal to avoid possible ﬂue gas leakage

and carbon monoxide emissions, which can lead to severe

personal injury or death.

10. Check breeching for sooting and clean if necessary. Install jacket top

panel and breeching.

11. Reconnect oil line and all electrical connections.

General description of control operation

Automatic air vent

Air is released when cap is unscrewed one turn. If air vent leaks, remove

small cap on top of vent, push in stem of valve and then release to clean

valve seat. Screw cap completely on, then unscrew one turn.

Water relief valve

Provides discharge if boiler pressure exceeds 30 psig.

Temperature limit control

If high boiler water temperature occurs, control shuts down burner, but allows

circulator to run as long as there is a call for heat. Limit should be set higher

than temperature needed for the system. Maximum limit setting is 220°F.

Circulator

Circulator provides forced water circulation through boiler and piping system.

Pressure-temperature gauge

Provides reading of boiler pressure and temperature. Maximum boiler

pressure is 50 psig, maximum water temperature is 220°F. Temperature

will vary according to system and daily heating demands. The range will

be from room temperature up to limit control setting.

Tankless water heater

Weil-McLain tankless heater ratings are based on 200°F boiler water tem-

perature. To get rated output, set tankless heater control to 200°F. Control

can be adjusted to meet system hot water requirements.

Expansion tank

As water heats up, it expands. Tank provides a place for increased water volume.

May be open, closed, or diaphragm-type. If relief valve opens frequently, expan-

sion tank may be water-logged. Drain tank and re-establish proper air cushion.

1. Open-type — Located above highest radiator or baseboard unit, usu-

ally in the attic or closet. Has a gauge glass and overﬂow pipe to drain.

2. Closed-type — Welded gas tight and located above boiler. Tank is par-

tially ﬁlled with water, leaving an air cushion for expansion.

3. Diaphragm-type — Welded gas tight with a rubber diaphragm to separate

air from water. Tank must be located near boiler before inlet to circulator.

An air vent must be installed in air vent tapping on boiler when this type

of tank is used. This eliminates air in system. Normal cold water ﬁll pres-

sure is 12 psig. Tank pressure may be checked with an air pressure gauge.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Handling ceramic ﬁber and ﬁberglass materials

REMOVAL OF COMBUSTION CHAMBER

LINING OR BASE PANELS

The combustion chamber lining or base insula-

tion panels in this product contain ceramic ﬁber

materials

that have been identiﬁed as carcinogenic,

or possibly carcinogenic, to humans

. Ceramic

ﬁbers can be converted to cristobalite in very

high temperature applications. The International

Agency for Research on Cancer (IARC) has con-

cluded, “Crystalline silica inhaled in the form of

quartz or cristobalite from occupational sources

is carcinogenic to humans (Group 1).”:

Precautionary measures

 Avoid breathing ﬁberglass dust and contact with skin

or eyes.

• Use NIOSH certiﬁed dust respirator (N95).

This type of respirator is based on the OSHA

requirements for ﬁberglass wool at the time this

document was written. Other types of respirators

may be needed depending on the job site condi-

tions. Current NIOSH recommendations can be

found on the NIOSH web site at http://www.

cdc.gov/niosh/homepage.html. NIOSH approved

respirators, manufacturers, and phone numbers are

also listed on this web site.

• Wear long-sleeved, loose ﬁtting clothing, gloves,

and eye protection.

 Apply enough water to the combustion chamber lining

or base insulation to prevent airborne dust.

 Remove combustion chamber lining or base insulation

from the boiler and place it in a plastic bag for disposal.

 Wash potentially contaminated clothes separately from

other clothing. Rinse clothes washer thoroughly.

NIOSH stated First Aid

 Eye: Irrigate immediately

 Breathing: Fresh air

REMOVAL OF FIBERGLASS WOOL

INSTALLATION OF FIBERGLASS WOOL

OR BASE PANELS:

This product contains ﬁberglass jacket

insulation and ceramic ﬁber materials in

combustion chamber lining or base panels

in gas ﬁred products. Airborne ﬁbers from

these materials have been listed by the State

of California as a possible cause of cancer

through inhalation.

Precautionary measures

 Avoid breathing ﬁberglass dust and contact with

skin or eyes.

• Use NIOSH certiﬁed dust respirator

(N95). This type of respirator is based

on the OSHA requirements for ﬁberglass

wool at the time this document was writ-

ten. Other types of respirators may be

needed depending on the job site condi-

tions. Current NIOSH recommendations

can be found on the NIOSH web site at

http://www.cdc.gov/niosh/homepage.html.

NIOSH approved respirators, manufactur-

ers, and phone numbers are also listed on

this web site.

• Wear long-sleeved, loose fitting clothing,

gloves, and eye protection.

 Operations such as sawing, blowing, tear out, and

spraying may generate airborne ﬁber concentra-

tion requiring additional protection.

 Wash potentially contaminated clothes separately

from other clothing. Rinse clothes washer thor-

oughly.

NIOSH stated First Aid

 Eye: Irrigate immediately

 Breathing: Fresh air

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Close clearance installation

Manual reset

temperature switch

Thermostat

44156

Figure 26 Manual reset temperature switch location Figure 27 Manual reset temperature switch wiring

Area above boiler

Bracket

1 to 5

inches

Manual reset

temperature

switch

Combustible surface

#6 X ½" Phillips

Sheet metal

screw

#10 X ½" Phillips

sheet metal screw

Close clearance installation

Substitute these instructions for corresponding material in manual.

All other procedures and practices must remain the same.

Recommended service and minimum clearances shown on page 8

should be used where possible. Where closer clearances are required:

• Top of boiler — If less than 24" available, provide removable

surface to allow for cleaning boiler ﬂue ways.

• Right or left side — Minimum 2 inches.

• Front — Minimum 2 inches from burner.

• Type “L” double-wall ﬂue pipe to combustible surface — as listed

in Table 6, page 35 and Figure 28 through Figure 30, page 35.

Jacket cap must be in place on boiler to avoid requiring

an 9" minimum clearance from back or top of boiler

to combustible material. Flue pipe clearances must

take precedence over jacket clearances.

1. Install boiler using clearances described at left.

2. Install barometric control 18-20 inches from boiler in breeching.

3. Attach manual reset temperature switch near upper surface of

enclosed area. See Figure 26.

4. Wire switch in series with thermostat. See Figure 27.

5. Provide two combustion/ventilation openings when installing in

conﬁned space. Size opening 140 sq. in. (1000 Btu) per 1 GPH

input. Locate openings near top and bottom of enclosed space.

To provide close clearances as described on pages 34 and 35:

Obtain the Close Clearance Kit, Weil-McLain Part No. 386-500-050. Install the kit as described below. Failure to use

kit or install as described can result in a ﬁre hazard, causing severe personal injury, death or substantial property

damage.

Burner adjustments

Final burner adjustments must be made using

combustion test equipment to assure proper

operation. Do not ﬁre boiler without water or

sections will overheat.

1. Refer to burner manual for start-up.

2. Allow boiler to heat to design condition.

3. Burner should be adjusted to 13% CO

or less with a

smoke level of zero and over-ﬁre of -0.01” to -0.02”. Re-

adjust burner combustion to account for environmental

conditions. Actual CO

value will vary and should be

adjusted for clean and safe combustion operation. Seasonal

variations as well as sufﬁcient combustion air supply can

affect proper combustion and boiler performance. The

burner should only be adjusted by a service professional

with appropriate instrumentation.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Dimension A

(When desired minimum

clearance from

Type “L” double-wall

vent pipe to combustible

surface is:)

Use the following

protection**:

½” thick insulation board

***

over one-inch glass ﬁber

or mineral wool batts+

24 gauge sheet metal with

one-inch ventilated air

space

½” thick insulation board

***

with one-inch ventilated

air space

* All clearances measured from outer surface of

equipment to combustible surface, not to the

protection used.

** Apply to combustible surface unless otherwise

noted. Cover all surfaces as specied in Table and

Figure25. icknesses are minimum.

*** Factory-fabricated board made of non-

combustible materials, normally bers, having

thermal conductivity in range of one (Btu-inch)/

(hr./sq. ./°F) or less.

+ Mineral wool batts (blanket or board), having min.

density of 8 lb./3 and a min. melting point of

1500°F.

Other dimensions available. Refer to NFPA-31.

Close clearance installation (continued)

Figure 28 Flue pipe clearances Figure 29 Back vent clearances

Figure 30 Top vent clearances

Table 6 Protection required for clearances

less than 6 inches from double-wall

vent pipe*

Combustible surface

Protection

Type "L"

double-wall

vent pipe

24" For servicing

or min. 2" For close

clearances

Combustible

surface

Combustible

surface

Note: 2" min. on sides

Combustible

surface

Combustible

surface

Note: 2" min. on sides

24" For

servicing

or min. 2"

For close

clearances

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Replacement parts

Repair parts must be purchased through Weil-McLain for the speciﬁc boiler as indicated in the list below. Results from

using modiﬁed or other manufactured parts will not be covered by warranty and may damage boiler or impair operation.

Table 7 WTGO Section and ﬂue collector part numbers for Series 4

Item Description Part No.

Front section w/heater opening

7013

316-700-260

Wide intermediate section

(WTGO-3) 7010

316-700-075

B Narrow intermediate section 7015 316-700-065

Intermediate section w/draw rod

lugs 7016

316-700-070

Back section w/7" ue, supply &

2" return 7027

316-700-235

Section replacement kit

(for 1 joint, includes seals, rope,

adhesive and collector hood

hardware) front or back section

386-700-852

Section replacement kit

(for 2 joints, includes seals, rope

and adhesive) intermediate

section

386-700-851

Section assembly, for WTGO-3 with

jacket & collector hood installed

386-701-038

Section assembly, for WTGO-4 with

jacket & collector hood installed

386-701-039

Section assembly, for WTGO-5 with

jacket & collector hood installed

386-701-040

Section assembly, for WTGO-6 with

jacket & collector hood installed

386-701-041

Section assembly only, for WTGO-3

386-700-978

Section assembly only, for WTGO-4

386-700-980

Section assembly only, for WTGO-5

386-700-981

Section assembly only, for WTGO-6

386-700-982

Section assembly only, for WTGO-7

386-700-662

Section assembly only, for WTGO-8

386-700-663

Section assembly only, for WTGO-9

386-700-664

Collector hood kit for WTGO-3*

386-700-337

Collector hood kit for WTGO-4*

386-700-337

Collector hood kit for WTGO-5*

386-700-338

F Collector hood kit for WTGO-6* 386-700-339

Collector hood kit for WTGO-7*

450-020-188

Collector hood kit for WTGO-8*

450-020-189

Item Description Part No.

Collector hood kit for WTGO-9*

450-020-190

G Tie rod ½ x 5½ (WTGO-7, 8, 9) 560-234-464

G Tie rod ½ x 10¾ (WTGO-7) 560-234-491

G Tie rod ½ x 12 (WTGO-7) 560-234-492

G Tie rod ½ x 14 (WTGO-3, 4, 8, 9) 560-234-470

G Tie rod ½ x 15 (WTGO-9) 560-234-495

G Tie rod ½ x 17 (WTGO-5) 560-234-472

G Tie rod ½ x 20 (WTGO-6) 560-234-534

G Tie rod ½ x 23¼ (WTGO-7) 560-234-538

G Tie rod 11/42 x 26 3/8 (WTGO-8) 560-234-542

G Tie rod ½ x 29½(WTGO-9) 560-234-497

Heater cover plate carton (cover

plate, gasket, studs, & nuts)

386-700-360

Combustion chamber kit (rear &

front Ref., Door ref. Blanket,

rope, blanket & water glass)

386-700-355

Burner mounting door assembly

(door, obs. port, rope, ins. & pins)

386-700-358

K Burner mounting door 7070 330-054-302

L Door hinge 7054 330-054-300

M Door refractory 386-700-359

N Door refractory blanket 591-222-115

P Observation port shutter 460-039-867

Q Door seal rope 5' 590-735-105

3/8" Glass rope for collector hood

(7' for largest size hood)

590-735-109

Flue cap assembly (cap, strap,

rope & screws)

386-700-344

Flue brush 123D 591-706-214

Blocked vent shutoff switch

(Canada only)

511-624-650

* Includes ue cap assembly, rope and hardware for

installation.

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Replacement parts (continued)

Figure 31 WTGO Section and ﬂue collector parts for Series 4

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Replacement parts (continued)

Table 8 WTGO Trim part numbers for Series 4

Item Description Part no.

Combination pressure-temperature gauge kit, 60° – 360° F., 0 - 75 psi,

31/8" dia., 1/4" NPT, short shank, with 1/4" x 1/2" reducing bushing

380-000-000

ASME pressure relief valve, set to relieve at 30 PSIG, 3/4" male inlet, 3

/4" female outlet

511-546-920

Electronic aquastat, high limit or combination high/low limit, with LWCO, high limit 100°–

220°, low limit 110°- 200°, circulator amps: 5.8 FLA, anticipator: 0.2 amps

381-300-000

Drain cock, 3/4" NPT, 11/2" shank 511-210-423

Drain cock, 3/4" NPT 511-246-392

5 Circulator

WTGO 3 & 4 – Taco 007e ECM 511-405-153

WTGO 3 - 6 – Taco 007 511-405-113

Circulator universal hardware kit 11/4" (Includes: (1) Flange, (1)

Gasket, (2) Screws and (2) nuts) for sizes 2, 3 & 4 only

381-354-526

Circulator universal hardware kit 11/2" (Includes: (1) Flange, (1)

Gasket, (2) Screws and (2) nuts) for sizes 5 & 6 only

381-354-531

7 Well 3/4" NPT, 6.25" long, extended shank type 592-300-027

8 Burner harness assembly 591-391-850

9 Barometric damper 510-512-267

10 Flue pipe brackets (set of 2) (Not shown) 426-700-268

Vent damper kits - Required for ENERGY STAR

compliance, (Version 3.0 Boilers speci-

cation of 87% AFUE), with reduced rates only

WTGO-3RD (Optional equipment)

WTGO-4RD (Optional equipment)

WTGO-5RD (Optional equipment)

WTGO-6RD (Optional equipment)

WTGO-7RD (Optional equipment)

Vent damper kit - Required for High Input nozzle installation

WTGO-3D, WTGO-3LD, WTGO-4D, WTGO-5D, WTGO-6D, and WTGO-7D

381-800-502

381-800-503

381-800-504

381-800-505

381-800-506

381-800-515

12 Outdoor - temperature sensor (Wireless) 386-701-047

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Replacement parts (continued)

Figure 32 WTGO Trim part for Series 4

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Replacement parts (continued)

Boiler

Size

Jacket panel with

insulation — front

Left side & rear Right side & rear

Top panel with

cap

WTGO-3L 381-355-962 381-355-963 381-355-982 381-355-969

WTGO-3 381-355-964 381-355-965 381-355-974 381-355-970

WTGO-4 381-355-964 381-355-966 381-355-974 381-355-971

WTGO-5 381-355-964 381-355-967 381-355-975 381-355-972

WTGO-6 381-355-964 381-355-968 381-355-976 381-355-973

Table 9 WTGO part numbers for Series 4

Common jacket parts for all boilers

Plastic ue cap cover with insulation 560-917-105

Jacket hardware kit 386-700-853

Touch up paint, Cloud spray can 381-359-278

Touch up paint, Slate spray can 384-000-141

Figure 33 WTGO Boiler jacket for Series 4

Complete Jacket cartons

3 section WTGO-3 416-700-468

3 section WTGO-3L 416-700-469

4 section 416-700-470

5 section 416-700-471

6 section 416-700-472

7 section 416-700-473

8 section 416-700-474

9 section 416-700-475

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Dimensions

6 ¼

[158.8]

29 ⁄

[750.9]

For 7

dia.

[177.8]

Vent pipe

Alternate

return

(“A”

boilers

only)

7 Dia.

[177.8]

7 ⁄

[182.6]

2 

[66.7]

15 ½

[393.7]

Approx.

7 Dia

[177.8]

7 Dia

[177.8]

Left side Front

Intermediate Back

14  [358.8]

Boiler Size WTGO-3L WTGO-3 WTGO-4 WTGO-5 WTGO-6 WTGO-7 WTGO-8 WTGO-9

inches

20 23

342.9 342.9 345.9 428.7 508 587.2 666.7 746.2

inches

20 22

349.2 428.7 428.7 508 587.2 666.7 746.2 825.5

Figure 34 WTGO dimensions — inches (mm)

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

DOE

Ratings

Table 10 WTGO Series 4 oil-red water boiler ratings

AHRI Certiﬁed Ratings

Boiler

Model

(9)

Burner Input

Heating

Capacity

Seasonal

Efciency

Net

Rating

(water)

Draft

Loss

Thru

boiler

Boiler

Water

Content

Flue

Outlet

Diameter

Minimum

Chimney

OVD

Damper

Required

GPH

(3)

MBH

(3)

MBH

(2)

AFUE

MBH

(2) (5)

In W.C.

(8)

Gallons

Inches

(7)

Rect.

Inches

Round

Inches

Height

Feet

Yes/No

WTGO-3LR 0.70 98 86

(4) 86.4 75 0.010

11.0 7 8 x 8 6 15

WTGO-3LD 0.95 133 115 (4) 86.0 100 0.010 Yes

WTGO-3R 0.80 112 98 (4) 86.2 85 0.020

14.9 7 8 x 8 6 15

WTGO-3RD 0.80 112 98 (4) 87.0 85 0.010 Yes

WTGO-3D 0.95 133 115 (4) 86.0 100 0.020 Yes

WTGO-4R 1.00 140 122 (4) 86.2 106 0.010

13.4 7 8 x 8 6 15

WTGO-4RD 1.00 140 123 (4) 87.0 107 0.010 Yes

WTGO-4D 1.20 168 146 (4) 86.0 127 0.010 Yes

WTGO-5R 1.20 168 147 (4) 86.1 128 0.015

15.9 7 8 x 8 7 15

WTGO-5RD 1.20 168 148 (4) 87.0 129 0.015 Yes

WTGO-5D 1.45 203 176 (11) 86.0 153 0.015 Yes

WTGO-6R 1.40 196 171 (4) 86.1 149 0.015

18.4 7 8 x 8 7 15

WTGO-6RD 1.40 196 173 (4) 87.0 150 0.015 Yes

WTGO-6D 1.75 245 213 (11) 86.0 185 0.015 Yes

WT GO-7R 1.60 224 196 (4) 86.0 170 0.015

20.8 7 8 x 8 8 15

WT GO-7RD 1.60 224 197 (4) 87.0 171 0.015 Yes

WTGO-7D 2.00 280 244 (11) 86.0 212 0.015 Yes

WTGO-8 2.30 322 266 (4)(6) - 231 0.025 23.3

7 8 x 12 8

20 No

WTGO-9 2.55 357 295 (4)(6) - 257 0.030 25.8 20 No

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.

Ratings

NOTES:

(1) WTGO boiler designed with convertible vertical and horizontal ue outlet.

(2) MBH refers to thousands of Btu per hour.

(3) Based on 140,000 Btu/gal.

(4) Based on standard test procedures prescribed by the United States Department of Energy at combustion condition of

13.5% CO

and -0.02" W.C. dra over re.

(5) Net AHRI ratings are based on net installed radiation of sucient quantity for the requirements of the building and

nothing need be added for normal piping and pick-up. Water ratings are based on a piping and pick-up allowance of

1.15.

An additional allowance should be made for unusual piping and pick-up loads.

(6) AHRI gross output.

(7) See page16 for minimum breeching diameter.

(8) Listed dra losses are for factory-shipped settings.

(9) Boiler model suxes: “R” designates a reduced input version. No separate/additional damper kit required. “D”

designates that the separate High Input OVD Automatic Vent Damper P/N 381-800-515 is required. “RD” designates

a reduced input version and the separate ES Vent damper is required (P/N 381-800-501 through 381-800-506).

(10) "L" designates a boiler with special front section (1½” supply tapping).

(11) Based on standard test procedures prescribed by the United States Department of Energy at combustion of 13.0%

and -0.02” W.C. dra over re.

NOTE: A burner nozzle change may be required - refer to the burner instructions or boiler’s rating label for correct

selection

Table 11 WTGO Series 4 oil-red water boiler rating notes

Part number 550-142-332/0421

WTGO

OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 4 — Boiler Manual

Weil-McLain WTGO SERIES 4 OIL-FIRED WATER BOILER WTGO-5R Residential Boilers

Product's Documents

User Manual

Specifications

Weil-McLain WTGO SERIES 4 OIL-FIRED WATER BOILER WTGO-5R Questions and Answers