Weil-McLain WGO User manual

Part number 550-141-826/1014
Thismanualmustonlybeusedbyaqualifiedheatinginstaller/servicetechnician.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.
• Installation
• Startup
• Maintenance
• Parts
Boiler Manual
Oil-Fired Water Boilers

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
When calling or writing about the boiler
Please have boiler model number and series from boiler rating label and CP number(s) from boiler jacket,
burner and controls. On page 28 of this manual is space to list CP number(s).
Packaged and non-packaged boilers
Packaged boilers, available only in sizes 2 through 6, are factory assembled, complete with block, jacket and
controls. Burner is shipped separately.
Non-packaged boilers, available in all sizes, 2 through 9, are shipped with block assembled, with jacket.
Controls, trim and burner shipped separately for field assembly.
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
Part number 550-141-826/1014
2
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

HOMEOWNER and SERVICE TECHNICIAN — read and follow completely.
Contents
Using this manual . . . . . . . . . . . . . . . . . . . . .2
When calling or writing about the boiler . . . . . . . .2
Packaged and non-packaged boilers. . . . . . . . . .2
Hazard denitions . . . . . . . . . . . . . . . . . . . . .2
Contents . . . . . . . . . . . . . . . . . . . . . . . . . .3
Please read before proceeding . . . . . . . . . . . . . .4
Tips for water systems — . . . . . . . . . . . . . . .4
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
WGO (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
Foundation . . . . . . . . . . . . . . . . . . . . . . .9
Install boiler — packaged boilers only . . . . . . . . . 10
Place boiler. . . . . . . . . . . . . . . . . . . . . . 10
Perform hydrostatic pressure test . . . . . . . . . . 10
Install boiler — non-packaged boilers only . . . . . . 12
Place boiler. . . . . . . . . . . . . . . . . . . . . . 12
Perform hydrostatic pressure test . . . . . . . . . . 14
Install jacket
(sizes 7 through 9 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 water piping . . . . . . . . . . . . . . . . . . 18
General piping information . . . . . . . . . . . . . .18
Install piping . . . . . . . . . . . . . . . . . . . . . 18
DIAPHRAGM expansion tank (Figure 9, page 19). . 18
CLOSED expansion tank (Figure 10, page 19) . . . 18
To connect WGO 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 wiring. . . . . . . . . . . . . . . . . . . . . . 22
General wiring requirements . . . . . . . . . . . . . 22
Thermostat wiring . . . . . . . . . . . . . . . . . . 22
3-Wire zone valve applications. . . . . . . . . . . . 22
Junction box (furnished) . . . . . . . . . . . . . . .23
Burner wiring . . . . . . . . . . . . . . . . . . . . . 23
High temperature limit . . . . . . . . . . . . . . . . 23
Connect wiring — blocked vent
shutoff switch option . . . . . . . . . . . . . . . . . . 25
Blocked vent shutoff switch . . . . . . . . . . . . . 25
Connect oil piping . . . . . . . . . . . . . . . . . . . . 26
General oil piping requirements . . . . . . . . . . . 26
Oil piping connection at burner. . . . . . . . . . . . 26
Start-up. . . . . . . . . . . . . . . . . . . . . . . . . . 27
Fill the system . . . . . . . . . . . . . . . . . . . . 27
When using antifreeze . . . . . . . . . . . . . . . .27
To place in operation . . . . . . . . . . . . . . . . .27
Check-out procedure . . . . . . . . . . . . . . . . . . 28
Check off steps as completed . . . . . . . . . . . . 28
Installation and service certificate . . . . . . . . . .28
Annual service check list . . . . . . . . . . . . . . . . 29
Controls requiring annual service . . . . . . . . . . 29
Detailed service procedures . . . . . . . . . . . . . . 30
Cleaning boiler flueways . . . . . . . . . . . . . . .30
General description of control operation . . . . . . .30
Handling ceramic ber and berglass materials . . . 31
Close clearance installation . . . . . . . . . . . . . . 32
Close clearance installation . . . . . . . . . . . . . 32
Burner adjustments for packaged
and non-packaged boilers . . . . . . . . . . . . . .32
Replacement parts . . . . . . . . . . . . . . . . . . . 34
Dimensions . . . . . . . . . . . . . . . . . . . . . . . 40
Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Part number 550-141-826/1014 3
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

HOMEOWNER and SERVICE TECHNICIAN — read and follow completely.
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 perform-
ing 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 flueways 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, reduc-
ing 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 compounds 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 hardness), 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 discon-
nect 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.
Please read before proceeding
Homeowner —
• For homeowner or person responsible for
simple start-up and routine maintenance of
the system
• Instructions on page 1 through page 7 must
be followed to assure proper operation of your
boiler. See page 7 for lists common problems
and possible corrections. In addition, it is your
responsibility to:
• Have boiler and burner installed by a quali-
fied installer.
• Have boiler and burner serviced annually
by a qualified service technician.
• Review and understand start-up and rou-
tine maintenance procedures with quali-
fied service technician.
• Perform routine maintenance as described
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 fol-
lowed to assure proper operation of this boiler.
• Annually service boiler and burner to assure
proper operation. See page 29 for service
record.
• Review and explain start-up and routine main-
tenance procedures with homeowner.
Follow instructions below to prevent
severe personal injury, death or sub-
stantial 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 chamber,
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 mount-
ing 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 routine
maintenance or service.
Part number 550-141-826/1014
4
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — 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 in-
structions 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.
Part number 550-141-826/1014 5
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

HOMEOWNER and SERVICE TECHNICIAN — read and follow completely.
Operation
WGO (see Figure 1)
1. If burner does not fire, check for:
• Service switch on boiler 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 WGO 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 Service switch on boiler
3 Water relief valve
4 Temperature-pressure gauge
5 Circulator
6 Limit control / low water
cut-off
7 Reset button on burner
primary control
8 Burner primary control
Part number 550-141-826/1014
6
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — 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.
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
flueway. Contaminated combustion
air supply.
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 boiler operation.
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.
OR
Domestic water from
tankless heater is always
lukewarm.
Mineral deposits insulate
internal waterways of heater.
Have qualified service technician delime 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 550-141-826/1014 7
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
Before installing boiler
Installations must comply with
• United States
• State and local plumbing, heating and electrical codes.
• National codes where applicable.
• Canada
• CanadianStandardsAssociation, CSA B139, Installation Code for Oil-
Burning Equipment.
• CSA C22.1 Canadian Electrical Code Part One.
• 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 26 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 coun-
ters, etc.) — see Appendix, page 32.
Top View
Walls
Floor
Ceiling
Wall
Figure 2 Recommended service clearances
Left side
A Provide 6" minimum clearance for service, provide 12"
minimum clearance for burner door swing.
B Minimum clearance from vent pipe to combustible mate-
rial: 6" for type “L” double-wall vent, 9" for single-wall
vent.
24"
A
A
A
BB
B
24"
Homeowner — STOP! The procedures and information on this and following pages are intended only for a quali-
fied 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.
Part number 550-141-826/1014
8
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
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
as less than 7200 cubic feet per 1 GPH input of all ap-
pliances in area. A room 8 ft. high x 33.5 ft. x 33.5 ft.
is 7200 cu. ft.).
Permanent Openings
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.
Inside air
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 equip-
ment that can pull air from room (including clothes
dryer and fireplace).
Outside air
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 require-
ments for 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 block-
age 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 equip-
ment to prove open before boiler operation.
Foundation
Lay a foundation, if needed. Boiler may be installed
on non-carpeted combustible flooring. Solid concrete
blocks can be used to create a pad.
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.
Before installing boiler (continued)
Installation instructions:
Packaged boiler — Continued on page 10
Non-packaged boiler — Continued on page 12
Boiler
model
Length
inches
Width
inches
Min.
height
inches
WGO-2 14 22 2
WGO-3 17 22 2
WGO-4 17 22 2
WGO-5 20 22 2
WGO-6 23 22 2
WGO-7 26 22 2
WGO-8 29 22 2
WGO-9 32 22 2
Table 1 Boiler foundation sizes
Part number 550-141-826/1014 9
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — 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 jacket cap on top of boiler.
b. Loosen two screws holding flue cap strap to collector hood. Remove
strap and flue cap from opening. Re-tighten screws.
c. Check rope placement inside flue cap.
(Read under step #6 below).
d. Loosen two 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. Snap jacket cap in back outlet opening.
Jacket cap must be in place on boiler to avoid requiring an 18”
minimum clearance from back or top 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 working pressure.
Do not leave boiler unattended. Cold
water fill can expand and damage cast
iron, resulting in severe personal injury,
death or substantial property damage.
6. Check for maintained gauge pressure for more
than 10 minutes. 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 550-141-826/1014
10
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — 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 continued on page 15.
Part number 550-141-826/1014 11
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
Install boiler — non-packaged boilers only
Fiberglass wool and ceramic fiber ma-
terials are possible cancer hazards. See
warning on page 31.
Place boiler
Non-Packaged WGO-2 through 6 —
position on site
Smaller sized boilers may be top heavy.
Use caution when handling to avoid mi-
nor personal injury or property damage.
Boiler is shipped for back flue outlet. To change to top
flue outlet (see Figure 3):
1. Loosen two screws holding flue cap strap to collec-
tor hood. Remove strap and flue cap from opening.
Re-tighten screws.
2. Check rope placement inside flue cap.
(Read under Step #3 on page 13.)
3. Loosen two 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.
Non-Packaged WGO-7, 8 & 9 — split the assembled
block for easier handling (see Figure 4, page 13)
1. Open burner mounting door and, using utility knife, slit floor insula-
tion at joint to be separated.
2. Remove 5½" draw rod and the longest draw rod from each side. Pull
block apart. Save draw rods, nuts, washers and sealing rings for reas-
sembly.
3. Move divided block to location.
4. Clean port openings with clean rag.
Do not use petroleum-based compounds to clean openings.
Damage to system components can result, causing property
damage.
5. Place rings in port openings. If ring slips out of groove, stretch ring
gently for several seconds, then place in groove.
6. Position sections so aligning lugs fit into sockets of next section. Make
sure sealing rope is in good condition and in position.
7. Oil threads on draw rods. Install washer and nut on end to be tightened.
Use nut only on other end.
8. 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.
9. 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.
10. Metal-to-metal contact should be made around port openings. If gap
does exist, it should be less than .020". Check with feeler gauge.
11. If gap around port openings exceeds .020", check for dirt on port
openings, sockets or misaligned lugs. If corrections are made and gap
still exists, contact your Weil-McLain distributor or sales office before
continuing installation.
Part number 550-141-826/1014
12
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
Install boiler — non-packaged boilers only (continued)
Non-Packaged WGO-7, 8 & 9 — install flue
collector hood (see Figure 4)
Obtain gas-tight seal to prevent possible flue gas
leakage and carbon monoxide emissions, leading
to severe personal injury or death.
1. Thread Tinnerman clip on screw so that clip fits snugly in
notch of hold-down lug. Screw must not turn.
2. 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.
3. Position flue collector hood on top of boiler sections and
over screws and clips as shown in Figure 4.
4. Install washers and nuts. Tighten nuts until collector hood
makes contact with Tinnerman clip.
5. Flue Cap
• 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. 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.
6. Check level. Shim legs, if needed.
Figure 4 Change from back flue outlet to top flue outlet (optional)
Sealing
rope in
groove
inside cap
Flue
cap
Flue cap
strap
Flue
collector
hood
Sealing
rope with
adhesive
tape
Nut
Washer
Tinnerman
clip
Screw Hold-down
lug
Separate
block here
for easier
handling
Part number 550-141-826/1014 13
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
Perform hydrostatic pressure test
1. See Figure 5 and Control Tapping table 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 1 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.
Figure 5 Control tapping locations
Front section
E3
R1
C
L
B1 H
N
Location Size Function
B1 1½" Return piping
B2 1½" Alternate return piping for
A/B WGO
C 1½" Supply piping
E3 1/4"Pressure-temperature
gauge
H ¾" Drain valve
L ¾" High limit control
N ½" Air vent or expansion
tank piping
R1 ¾" Relief valve
Table 2 Control tappings
B2
Back section
Install boiler — non-packaged boilers only (continued)
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
(sizes 7 through 9 only)
Before installing jacket, remove burner mounting door. See jacket
instructions for details.
Install boiler controls
See Control Tapping Table and Figure 5 and Figure 6, page 15
to install controls.
1. Install limit control. If not furnished, use high limit with
maximum 220°F setting.
2. Affix CP number label(s) on jacket front panel.
Part number 550-141-826/1014
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GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
Figure 6 Water boiler controls
Install burner
(also refer to instructions packed with
burner)
Use only burners specified for use on
Weil-McLain GOLD oil boilers. DO
NOT use burners specified for use on
Weil-McLain Model 68 boilers. Contact
individual burner manufacturers for
proper burner selections.
Relief
valve
Water
pressure-temperature
gauge
Limit control / low water cut-off
Drain valve
Circulator
For P-WGO and A-WGO boiler:
1. Secure universal mounting flange and gasket to burner mounting door.
Use three bolts provided.
2. Secure burner on flange with three bolts.
3. Position burner so end of air tube is level to 1½° tilt downward. 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. Securely close door with nut.
Install burner — all boilers
Part number 550-141-826/1014 15
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
Connect breeching
General chimney requirements
• Designed for natural draft firing. Connect boiler to vertical chimney.
• 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, Installation of Oil-Burning Equipment.
• NFPA 211, Standard for Chimneys, Fireplaces,Vents and Solid Fuel
Burning Appliances.
• In Canada, refer to CSA B139, Installation Code for Oil-Burning
Equipment.
• 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:
• 6 inches — Type “L” double-wall vent
• 9 inches — Single-wall vent
• Minimum chimney sizes should be used.
Oversized chimneys, outside masonry chimneys and/or
derated inputs can result in condensation in chimney.
Connect breeching:
Long horizontal breechings, excessive number 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 2 flue pipe brackets.
2. Connect full-sized breeching when possible. See Minimum Chimney
Size Table.
• Back outlet — see Figure 7, page 17.
• Top outlet — see Figure 8, page 17.
3. 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.
4. When burner and boiler are properly installed, draft
overfire 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.
5. An induced draft fan for the chimney may be
necessary 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.
Boiler
model
number
Minimum
breeching
diameter
(note 3)
Minimum
AHRI
chimney size
Minimum
chimney
height
Rect. Round
WGO-2 5" 8" x 8"
(note 1) 6" 15'
WGO-3
WGO-4 6"
WGO-5 6" 8" x 8"
(note 1) 7" 15'WGO-6 7"
WGO-7
WGO-8 7" 8" x 12"
(note 2) 7" 20'
WGO-9
Note 1 6¾" x 6¾" inside liner
Note 2 6½" x 10½" inside liner
Note 3 Flue collar on boiler is 7" diameter
Table 3 Minimum chimney sizes
Part number 550-141-826/1014
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GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
Connect breeching (continued)
Figure 7 Back outlet breeching connection
Figure 8 Top outlet breeching connection
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)
Part number 550-141-826/1014 17
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
General piping information
• All packaged WGO boilers are shipped with an installed
combination temperature limit control/low water cut-off.
• If installation is to comply with ASME or Canadian
requirements, an additional high temperature limit is
needed. 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 al-
lowable set point is 220°F. Wire control as shown on
wiring diagram.
• Use backflow check valve in cold water supply as required
by local codes.
Install piping
• See Figure 9 or Figure 10, page 19, and Table 4, page 18
for near-boiler piping and single-zone piping. See page 20
to complete multiple-zone piping or page 21 to complete
piping for systems operating below 140°F.
• For multiple-boiler piping, refer to Weil-McLain’s “Pri-
mary/Secondary Piping Guide” and “M-WGO Multiple
Boiler Manual.”
• Install relief valve vertically in “R1” tapping on front
of boiler. See Figure 9 or Figure 10 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 9, 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 9.
CLOSED expansion tank
(Figure 10, 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 Figure
9 to expansion tank. Use ½" N.P.T. piping. Pitch
any horizontal piping up towards tank 1 inch per
5 feet of piping.
To connect WGO boilers to
indirect-fired water heaters
Install and wire per water heater manual provided with
water heater.
Connect water piping
Boiler model
number To system From system
WGO-2 1" 1"
WGO-3 1¼" 1¼"
WGO-4 1¼" 1¼"
WGO-5 1½" 1½"
WGO-6 1½" 1½"
WGO-7 1½" 1½"
WGO-8 2" 2"
WGO-9 2" 2"
* All piping sizes based on 20°F
temperature rise through boiler.
Table 4 Water piping sizes
Part number 550-141-826/1014
18
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
Connect water piping (continued)
Figure 9 Piping with DIAPHRAGM expansion tank
Figure 10 Piping with CLOSED expansion tank
Isolation
valve
From
system
Isolation valve
Cold water fill
To system
“C” tapping
“N” tapping
Circulator
(Alternate circulator location) “B1” tapping
Relief
valve
Circulator
Closed type expansion tank
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 550-141-826/1014 19
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual

SERVICE TECHNICIAN ONLY — read and follow completely.
Zone 2
Zone 1
1
2
55
1
2
1
3
1
Piping MULTIPLE ZONES
1. Follow instructions on page 18 and page 19 to
install piping near boiler.
2. See Figure 11 or Figure 12 to complete installation
3. Zoning with circulators:
a. Size each circulator to individual circuit re-
quirements.
b. Remove circulator (when furnished as standard
equipment).
c. Install balancing valves to adjust flow to distrib-
ute heat to all zones.
d. Separate relay is required for each circulator.
4. Zoning with zone valves:
a. Install balancing valves to adjust flow to distrib-
ute heat to all zones.
b. Separate transformer is required to power zone
valves. Refer to “Weil-McLain Zone Valve Wir-
ing Guide” for details.
Connect water piping (continued)
Figure 12 Multiple zoning with ZONEVALVES
Zone 2
Zone 1
1
4
5
5
1
1
1
Figure 11 Multiple zoning with CIRCULATORS
Legend
1 Isolation valve
2 Flow control valve
3 Circulator
4 Zone valve
5 Drain valve
Part number 550-141-826/1014
20
GOLD WGO OIL-FIRED NATURAL DRAFT WATER BOILER — SERIES 3 — Boiler Manual