Weil-McLain PFG-7 User Manual
Gas-fired
water boiler
PFG
• Installation
• Service
Series 7
• Operation
• Parts
For additional information,
refer to . . .
Control Supplement
Read all instructions before installing
This manual must only be used by a qualified heating installer/service technician.
Read all instructions before installing. Perform steps in the order given. Failure
to comply could result in severe personal injury, death or substantial property
damage.
Installer Leave all instructions with boiler for future reference.
Any claims for damage or shortage in shipment must be filed immediately against
the transportation company by the consignee.
Owner Installation and service must be performed by qualified contractor.
Part No. 550-110-641/0605
PFG SerieS 7 GaS-Fired Water Boiler — Boiler Manual
Contents
Section I: Installation 2-14
Codes ................................................................. 2
Combustion air and ventilation openings............ 3
Select the boiler location .................................... 3
Installation clearances ........................................ 3
Chimney or vent requirements ........................... 4
When removing boiler from common vent .......... 4
Boiler foundation ................................................ 5
Placing the boiler ................................................ 5
Residential garage installation ........................... 5
Hydrostatic pressure test .................................... 5
Boiler piping connections . . ............................... 6
Recommended piping ........................................ 6
Multiple zoning ................................................... 7
Filling the system ................................................ 7
Bypass piping ..................................................... 8
External heat exchangers ................................... 9
Freeze protection ................................................ 9
Using with refrigeration system .......................... 9
Size and install gas piping ........................... 10-11
Draft hood installation ....................................... 12
Spill switch installation ...................................... 12
Damper installation ........................................... 12
Breeching erection ........................................... 12
Wiring ............................................................... 12
Install room thermostat ..................................... 12
Wiring multiple zones ....................................... 13
Canadian installations – chain and s-hook ....... 13
Checkout procedure ......................................... 14
Section II: Service 15-19
Section III: Replacement Parts 20-21
Section IV: Ratings, Dimensions 22-23
Hazard definitions
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.
Read before proceeding
The boiler contains ceramic fiber and fiberglass materials.
Use care when handling these materials per instructions on
page 15 of this manual. Failure to comply could result in severe
personal injury.
Do not use petroleum-based cleaning or sealing compounds
in boiler system. Severe damage to system components can
result, causing substantial property damage.
Read all instructions before installing. Failure to follow all
instructions in proper order can cause severe personal injury,
death or substantial property damage.
When calling or writing about the boiler—
Please have the boiler model number from
the boiler rating label and the CP number
from the boiler jacket. You may list the
CP number in the space provided on the
Installation and service certificate
found on page 14.
Codes
Installation must comply with all local codes, laws,
regulations and ordinances. Also United States National
Fuel Gas Code ANSI Z223.1-latest edition. When required, the installation must conform to Standard for
Controls and Safety Devices for Automatically Fired
Boilers, ANSI/ASME CSD-1. Safe lighting and other
performance criteria were met with the gas manifold
and control assembly provided on the boiler when the
boiler underwent tests specified in ANSI Z21.13-latest
edition.
Canadian installations must comply with CAN/CSA
B149.1 or .2 Installation Codes. The equipment shall be
installed in accordance with those installation regulations in force in the local area where the installation is
to be made. These shall be carefully followed in all cases.
Authorities having jurisdiction shall be consulted before
installations are made.
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Part Number 550-110-641/0605
PFG SerieS 7 GaS-Fired Water Boiler — Boiler Manual
Section I: Installation
Combustion air and ventilation openings
Combustion air and ventilation openings must comply with Section 5.3, Air for Combustion and Ventilation, of National Fuel
Gas Code ANSI Z223.1-latest edition, or applicable local building codes. Canadian installations must comply with CAN/CSA
B149.1 or .2 Installation Codes.
Provide adequate combustion and ventilation air to:
• Ensure proper combustion
• Reduce risk or severe personal injury or
death from flue gas spillage and carbon
monoxide emissions.
Do not install an exhaust fan in the boiler room.
Boiler installation must ensure sufficient openings in building
and boiler room to provide adequate combustion air and ventilation. Consider construction tightness of building when deciding
whether additional outside openings may be needed.
Older buildings with single-pane windows, minimal weatherstripping 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.
Select the boiler location
• Consider all connections to boiler before selecting a location.
• Boiler must be installed so gas control system components are pro
tected from dripping or spraying water or rain during operation or
service.
• Non-combustible floor ONLY. See “Boiler foundation”, Page 5.
To avoid personal injury, death or property damage,
keep boiler area clear and free from combustible
materials, gasoline and other flammable vapors
and liquids.
Installation clearances
Suggested minimum clearances for servicing
• 24 inches for cleaning and servicing, left side.
• 18 inches for access to controls and components, front.
• 48 inches from top for cleaning flueways.
• 6 inches on remaining sides.
PFG-5 through PFG-7: Required minimum clearances
to combustible surface in alcove installations (see
below)
PFG 5 thru 7: Top 42” R. Side 5” Front: Alcove 18”
Rear 5” L. Side 5”
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Air from inside building (boiler in interior room):
• Tightly constructed buildings must be provided with openings to
outside for combustion and ventilation air. These openings must be
sized to handle all fuel burning appliances, exhaust and ventilation
fans and fireplaces.
• When openings to boiler room are taken to interior spaces, provide
two permanent openings: a combustion air opening within 12 inches
of floor and a ventilation opening within 12 inches of ceiling. Each
opening must provide a minimum free area of one square inch per
1,000 Btuh input of all appliances in room plus requirements for
any exhaust fans in room. The interior space supplying combustion
and ventilation air must have adequate infiltration from outside.
Air directly from outside to boiler room:
• Tightly constructed buildings must be provided with combustion
air and ventilation openings to boiler room which are adequate to
handle the boiler needs plus the needs of all other fuel-burning appliances, fireplaces and exhaust or ventilation fans.
• Combustion and ventilation openings connecting directly or by
ducting to outside, or to attic or crawl spaces that freely connect
with outside, must be sized as follows:
1. Outside wall or vertical ducting - one square inch per 4,000
Btuh input of all appliances in room plus requirements for any
exhaust fans or other appliances in room.
2. Horizontal ducting - one square inch per 2,000 Btuh of all appli
ances in room plus requirements for any exhaust fans or other
appliances in room.
3. All ducting must be same size as permanent openings. Minimum
size of ducting must be no less than 9 square inches.
4. Other size ducting must comply with local codes.
PFG-8: Required minimum clearances to combustible
surfacel in alcove installations
PFG 8: Provide minimum 24” between jacket and any com
bustible wall(s). Provide minimum 48” between jacket top and
combustible ceiling or surface above the boiler.
Install in a space large in comparison to size of boiler.
Clearances from piping materials to combustible surfaces
• Single wall vent pipe must be at least 6 inches from combustible
surface.
• Type “B” double wall metal vent pipe - refer to vent manufacturer’s
recommendation for clearances to combustible surface.
• Hot water pipes must be at least ½” from combustible surface.
Note Minimum clearances from combustible
surfaces for models PFG-5 through PFG-7
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PFG SerieS 7 GaS-Fired Water Boiler — Boiler Manual
Chimney or vent requirements
(also refer to Breaching erection, Page 12)
Venting must be installed according to Part 7, Venting of
Equipment, of National Fuel Gas Code, ANSI Z223.1latest edition and applicable building codes. Canadian
installations must comply with CAN/CSA B149.1 or .2
Installation Codes.
Minimum chimney or vent sizes are on page 22. A chimney or vent without a listed cap should extend at least
3 feet above the highest point where it passes through
a roof of a building and at least 2 feet higher than any
portion of a building within a horizontal distance of 10
feet. A chimney or vent must not extend less than those
distances stated above.
A lined chimney is preferred and must be used when
required by federal, provincial, territorial, state or local
building codes. Vitreous tile linings with joints which
prevent the retention of moisture and linings made
of corrosion-resistant materials are best. Advice for
flue connections and chimney linings can usually be
obtained from the local gas utility. Type “B” double
wall metal vent pipe or single wall vent pipe may be
used as a liner.
Cold masonry chimneys, also known as outside chimneys, typically have one or more walls exposed to
outside air.
When any atmospheric gas-fired boiler with automatic
vent damper is vented through this type of chimney, the
potential exists for condensation to occur. Condensation
can damage a masonry chimney.
Weil-McLain recommends the following to prevent
possible damage:
1. Line chimney with corrosion-resistant metal liner such as
AL29-4C® single wall stainless steel or B-vent. Size liner
per National Fuel Code ANSI Z223.1-latest edition.
2. Provide drain trap to remove any condensate.
Inspect existing chimney or vent before
installing boiler. Failure to clean or replace
perforated pipe or tile lining will cause
severe injury or death.
Do not alter boiler draft hood or place
any obstruction or non-approved damper
in the breeching of vent system. CSA
certification becomes void. Flue gas
spillage and carbon monoxide emissions
will occur causing severe personal injury
or death.
Where two or more gas appliances vent into a common
chimney or vent, equivalent area should be at least equal
to the area of the vent outlet on the largest appliance
plus 50 percent of the area of the vent outlet on the additional appliance(s).
When removing boiler from
common venting system
Failure to follow all instructions listed
below can cause flue gas spillage and
carbon monoxide emissions, resulting in
severe personal injury, death or substantial
property damage.
At the time of removal of an existing boiler, the following
steps shall be followed with each appliance remaining
connected to the common venting system placed in operation, while the other appliances remaining connected
to the common venting system are not in operation.
a. Seal any unused openings in the common venting sys-
tem.
b. Visually inspect the venting system for proper size and
horizontal pitch and determine there is no blockage or
restriction, leakage, corrosion and other deficiencies which
could cause an unsafe condition.
c. Insofar as is practical, close all building doors and windows
and all doors between the space in which the appliances
remaining connected to the common venting system are
located and other spaces of the building. Turn on clothes
dryers and any appliance not connected to the common
venting system. Turn on any exhaust fans, such as range
hoods and bathroom exhausts, so they will operate at
maximum speed. Do not operate a summer exhaust fan.
Close fireplace dampers.
d. Place in operation the appliance being inspected. Follow
the lighting instructions. Adjust thermostat so appliance
will operate continuously.
e. Test for spillage at the draft hood relief opening after
5 minutes of main burner operation. Use the flame of
a match or candle, or smoke from a cigarette, cigar or
pipe.
f. After it has been determined that each appliance remain
ing connected to the common venting system properly
vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers, and any other gasburning appliance to their previous conditions of use.
g. Any improper operation of the common venting system
should be corrected so the installation conforms with the
National Fuel Gas Code, ANSI Z223.1-latest edition. When
resizing any portion of the common venting system, the
common venting system should be resized to approach
the minimum size as determined using the appropriate
tables in Part 11 in the National Fuel Gas Code, ANSI
Z223.1-latest edition.
Canadian installations must comply with CAN/CSA
B149.1 or B149.2 Installation Code.
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PFG SerieS 7 GaS-Fired Water Boiler — Boiler Manual
Boiler foundation
Never install boiler on combustible flooring or
carpeting, even if a concrete or aerated foundation
is used. Severe personal injury, death or substantial
property damage can result.
1. See Figure 1. A level concrete or solid brick pad is required if:
a) There is a possibility of the floor becoming flooded.
b) Non-level conditions exist.
2. An aerated boiler foundation is recommended if any of the following
conditions exist:
a) Electrical wiring or telephone cables buried in the concrete floor
of the boiler room.
b) Concrete floor is “green.”
c) There is a history of the floor becoming flooded.
d) Water is channeled under the concrete.
Figure 1 Boiler foundation
Placing the boiler
1. Remove boiler from shipping pallet. Do not drop boiler or bump
jacket on floor or pallet.
2. Level boiler so that the built-in air separation will work correctly.
Shim legs if necessary. Do not alter legs.
3. Remove front jacket door and burner access panel. Unscrew access
panel screws, remove and discard shipping washers, and reinstall
screws.
4. Check for proper orifice sizing from charts below.
Proper orifices must be used. Failure to do so will
cause severe personal injury, death or substantial
property damage.
5. Level and straighten the burners.
Burners must be seated properly in locating slots
with their openings facing up. Gas orifices must
inject down the center of the burner. Failure to
properly seat burners will result in severe personal
injury, death or substantial property damage.
6. Reinstall access panel.
Residential garage installation
Install boiler so burners are at least 18 inches above the floor.
Hydrostatic pressure test
Pressure test before attaching gas piping or electrical supply.
1. Plug any necessary boiler tappings or openings.
2. Connect water supply. Fill boiler and purge all air. Test at 45 psi for
more than 10 minutes.
Do not leave boiler unattended. A cold water
fill could expand and cause excessive pressure,
resulting in severe personal injury, death or
substantial property damage.
3. Check for maintained gauge pressure and leaks. Repair if found.
Leaks must be repaired at once. Failure to do so
can cause boiler damage, resulting in substantial
property damage.
Do not use petroleum-based sealing compounds in
boiler system. Severe damage to boiler will result,
causing substantial property damage.
4. Drain boiler and remove testing plugs.
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PFG SerieS 7 GaS-Fired Water Boiler — Boiler Manual
Boiler piping connections to the heating
system (refer to piping diagrams, Page 7)
Failure to properly pipe the boiler may result in
improper operation and damage to the boiler or
building.
These boilers are provided with built-in air elimination systems.
1. Install relief valve vertically in top ¾” tapping in right end section.
See WARNING following.
To avoid water damage or scalding due to relief
valve operation:
• Discharge line must be connected to relief valve
outlet and run to a safe place of disposal. Terminate
the discharge line to eliminate possibility of severe
burns should the valve discharge.
• Discharge line must be as short as possible and be
the same size as the valve discharge connection
throughout its entire length.
• Discharge line must pitch downward from the valve
and terminate at least 6” above the floor drain where
any discharge will be clearly visible.
• The discharge line shall terminate plain, not threaded, with a material serviceable for temperatures of
375 °F or greater.
• Do not pipe the discharge to any place where freezing could occur.
• No shutoff valve shall be installed between the
relief valve and boiler, or in the discharge line. Do
not plug or place any obstruction in the discharge
line.
• Failure to comply with the above guidelines could
result in failure of the relief valve to operate, resulting in possibility of severe personal injury, death or
substantial property damage.
• Test the operation of the valve after filling and pressurizing system by lifting the lever. Make sure the
valve discharges freely. If the valve fails to operate
correctly, replace it with a new relief valve.
2. Install pressure-temperature gauge in tapping provided in left end
section.
3. This boiler is for forced hot water circulation only. The circulator and
expansion tank must be selected and sized according to the design
requirements of the system.
a) Size and install circulator. Can be installed on supply or return
piping
b) Size expansion tank to handle the volume of water in the sys
tem.
4. Expansion tank installations.
a) Closed type expansion tanks - connect from the ¾” N.P.T.
expansion tank tapping on the left end section (located just
behind the supply outlet tapping) to the expansion tank using
¾” N.P.T. piping. Any horizontal expansion tank piping must
pitch upward toward the tank at least 1 inch for each 5 feet of
piping.
b) Diaphragm type expansion tank - may be located anywhere in
the system, preferably near the boiler.
A manual or automatic type air vent must be
installed in the ¾” N.P.T. tapping when a diaphragm
type tank is used.
The most common cause of lime deposits in boilers is inadequate
expansion tank volume. If the expansion tank is too small, system
water is lost from the relief valve and make-up water is added
through the fill valve. Eventual section failure will result.
5. Connect the system supply piping to the supply outlet tapping on
the left end of the boiler. See Figure 2a for minimum pipe size.
6. Connect the system return piping to the return tapping on the right
end of the boiler. See Figure 2a for minimum pipe size.
7. Install drain valve provided with boiler on left side. The installer
must provide a drain cock to drain the right (return) side of the
boiler and its connecting piping. The drain cock on the left side of
the boiler will not fully drain the right side.
8. Low water cut off:
a) Must be installed on any PFG boiler if the boiler is located above
radiation level.
b) Must be installed on all PFG-8 boilers to meet ASME specifica
tions (low water cut-off not supplied by Weil-McLain).
c) May be required by certain state, local or territorial codes or
insurance companies.
If a low water cut-off is required, use a control designed especially
for water installations. An electrode probe type low water cut-off
may be located in a tee in the supply line above the boiler.
9. If the system is to be ASME inspected and approved, an additional
high temperature limit is needed. Purchase and install the control
in the supply outlet piping to the boiler.
Figure 2a Minimum recommended pipe sizes
(Supply and return sizes refer to minimum size of
pipe connected to the boiler for 20°F temperature
drop between supply and return.)
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Part Number 550-110-641/0605
PFG SerieS 7 GaS-Fired Water Boiler — Boiler Manual
Figure 2b Piping – Closed type expansion tank
Use circulators or zone valves in each circuit for multiple
circuit applications.
Figure 2c Piping – Closed diaphragm type expansion tank
Use circulators or zone valves in each circuit for multiple
circuit applications.
Multiple zoning
1. Zone valves:
a) Refer to zone valve manufacturer’s literature for wiring
and application. A separate transformer is required to
power zone valves.
b) Provide balancing valves to adjust the flow so it is
about the same in each zone.
2. Circulators:
a) Zoning with circulators requires a relay for each cir
cuit.
b) Install flow control valves to prevent gravity circula
tion.
c) Provide balancing valves to adjust the flow so it is
about the same in each zone.
d) Size common return and supply piping for total flow
of all circulators.
Filling the system
1. Close manual air vents, drain cock, and automatic air vent,
if used.
2. Fill to correct system pressure. Correct pressure will vary
with each application. Residential systems are often designed for 12 pounds cold fill pressure.
3. Open automatic air vent one turn, if used.
4. Air must be vented for the system. Air in the system can
interfere with water circulation and cause improper heat
distribution.
a) Open manual water feed valve.
b) Starting on the lowest floor, open the air vents one at
a time until water squirts out. Close vent.
c) Repeat with remaining vents.
d) Close manual water feed valve when correct boiler
pressure is reached.
5. To purge air from system, install isolation valve in return
piping.
a) Connect a garden hose to the purge valve located
above the isolation valve.
b) Close isolation valve. Open purge valve.
c) Open hand water feed valve and allow system to purge
all air. If system has more than one circuit, purge each
circuit separately by opening each balancing valve one
at a time.
d) Close purge valve.
e) Open isolation valve.
f) Fill the system to the correct pressure.
6. Keep the system filled by occasionally opening the air
vents as in Step 4 above. Add water to make up system
pressure.
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Part Number 550-110-641/0605
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PFG SerieS 7 GaS-Fired Water Boiler — Boiler Manual
Bypass piping
Bypass piping is not normally required on
any baseboard system.
Bypass piping should be used for the following installations. (Bypass, supply, and return piping should be
same size.)
1. Use the piping shown in Figure 3 to protect:
• radiant panels, plaster, etc. from high temperature
water supplied from boiler, or
• boiler from condensation caused by low temperature
water returned from system.
2. Use the piping shown in Figure 4 to protect boiler from
condensation formed by low water temperature returned
from large water content converted gravity systems, etc.
Figure 3
Figure 4
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Part Number 550-110-641/0605
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