National Products BW3 User Manual
Installation, Start-Up, and Operating Instructions
Gas-Fired
Induced-Draft Hot Water Boilers
BW3
Series B
Sizes 42,500 through 225,000
®
NOTE: Read the entire instruction manual before starting the installation. These instructions must be affixed on or adjacent to the boiler.
This symbol → indicates a change since the last issue.
CANADIAN GAS ASSOCIATION
APPROVED
R
MODEL BW3
ama
ASME
®
A95465
Index Page
SAFETY CONSIDERATIONS.....................................................................................................................................................................................2
INTRODUCTION..........................................................................................................................................................................................................3
BOILER RATINGS AND CAPACITIES.................................................................................................................................................................3-4
LOCATING THE BOILER.......................................................................................................................................................................................4-5
FRESH AIR FOR COMBUSTION...........................................................................................................................................................................5-6
Boiler Located in Unconfined Space.......................................................................................................................................................................5
Boiler Located in Confined Space .......................................................................................................................................................................5-6
INSTALLATION—SYSTEM PIPING .....................................................................................................................................................................6-7
For Use with Cooling Units.....................................................................................................................................................................................7
Low Design Water Temperature Systems (Below 140°F) .....................................................................................................................................7
Form: IM-BW3A-05 Cancels: IM-BW3A-04 Printed in U.S.A. 8-99 Catalog No. 63BW-3A1
CHIMNEY AND VENT PIPE CONNECTION .......................................................................................................................................................7-9
Checking Chimney....................................................................................................................................................................................................8
Minimum Vent Pipe Clearance................................................................................................................................................................................8
Removing Existing Boiler from Common Venting System....................................................................................................................................9
OPTIONAL HORIZONTAL VENTING WITH POWER VENTER ....................................................................................................................9-10
GAS SUPPLY PIPING ..........................................................................................................................................................................................10-11
Checking Gas Supply .............................................................................................................................................................................................10
Connecting Gas Piping......................................................................................................................................................................................10-11
Checking Gas Piping..............................................................................................................................................................................................11
ELECTRICAL WIRING..............................................................................................................................................................................................12
Electric Power Supply............................................................................................................................................................................................11
Installing Thermostat..............................................................................................................................................................................................11
Wiring Diagram......................................................................................................................................................................................................12
SEQUENCE OF OPERATION...................................................................................................................................................................................11
EQUIPMENT AND OPTIONAL ACCESSORIES ..............................................................................................................................................13-14
Relief Valve............................................................................................................................................................................................................13
Expansion Tank (Optional) ....................................................................................................................................................................................13
Diaphragm-Type Expansion Tank (Optional)........................................................................................................................................................13
Air-Eliminating Fitting (Air Purger) (Optional)....................................................................................................................................................13
Main Air Vent for Downflow Systems or Diaphragm-Type Expansion Tank (Optional) ..................................................................................13
Automatic Fill Valve (Optional)............................................................................................................................................................................13
Drain Valve.............................................................................................................................................................................................................13
Water Temperature Control....................................................................................................................................................................................13
Circulating Pump....................................................................................................................................................................................................14
Blower (Draft Inducer)...........................................................................................................................................................................................14
Pressure Switch.......................................................................................................................................................................................................14
Rollout Switch (Flame Rollout Safety Shutoff)....................................................................................................................................................14
STARTING BOILER...................................................................................................................................................................................................14
How a Hot Water System Operates.......................................................................................................................................................................14
Filling System with Water......................................................................................................................................................................................14
FOR YOUR SAFETY READ BEFORE OPERATING.......................................................................................................................................14-15
GAS VALVE OPERATING INSTRUCTIONS.........................................................................................................................................................15
CHECKING AND ADJUSTING................................................................................................................................................................................16
Gas Valve Safety Shutdown Test ..........................................................................................................................................................................16
Pilot Burner Adjustment.........................................................................................................................................................................................16
Main Burner Air Adjustment .................................................................................................................................................................................16
Limit Controls Adjustment.....................................................................................................................................................................................16
Thermostat Heat Anticipator Adjustment..............................................................................................................................................................16
Safety Controls Check............................................................................................................................................................................................16
MAINTAINING BOILER......................................................................................................................................................................................17-18
Burners....................................................................................................................................................................................................................17
Relief Valve............................................................................................................................................................................................................17
Expansion Tank ......................................................................................................................................................................................................17
Boiler Flue Passages...............................................................................................................................................................................................17
Vent Pipe.................................................................................................................................................................................................................17
Water System..........................................................................................................................................................................................................17
Cleaning Boiler and Burners.............................................................................................................................................................................17-18
Blower.....................................................................................................................................................................................................................18
SERVICE HINTS ........................................................................................................................................................................................................19
REPAIR PARTS.....................................................................................................................................................................................................20-23
SAFETY CONSIDERATIONS
Installing and servicing heating equipment can be hazardous due to gas and electrical components. Only trained and qualified personnel should
install, repair, or service heating equipment. Untrained personnel can perform basic maintenance functions such as maintaining water level. All
other operations must be performed by trained service personnel. When working on heating equipment, observe precautions in literature, on tags,
and on labels attached to or shipped with unit and other safety precautions that may apply.
→
Follow all safety codes. In the United States, follow all safety codes including the National Fuel Gas Code (NFGC) NFPA 54-1999/ANSI
Z223.1-1999. In Canada, refer to the current edition of the National Standard of Canada CAN/CGA-B149.1- and .2-M95 Natural Gas and Propane
Installation Codes (NSCNGPIC). Wear safety glasses and work gloves. Have fire extinguisher available during start-up and adjustment procedures
and service calls.
Recognize safety information. This is the safety-alert symbol
potential for personal injury.
→
Understand the signal words DANGER, WARNING, CAUTION, and NOTE. These words are used with safety-alert symbol. DANGER identifies
most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in personal injury or
death. CAUTION is used to identify unsafe practices which would result in minor personal injury or product and property damage. NOTE is used
to highlight suggestions which will result in enhanced installation, reliability, or operation.
. When you see this symbol on unit or in instructions and manuals, be alert to
—2—
INTRODUCTION
This boiler cannot be used with all types of chimneys. Read these instructions carefully before installing.
These Gas-Fired Hot Water Boilers are low-pressure, sectional cast iron boilers design certified by the American Gas Association (A.G.A.) and
Canadian Gas Association (C.G.A.) for use with natural and propane gases. They are constructed and hydrostatically tested for a maximum
working pressure of 50 psi in accordance with the American Society of Mechanical Engineers (A.S.M.E.) Boiler and Pressure Vessel Code Section
IV Standards for cast iron heating boilers.
Check to be sure boiler size is correct before starting installation. See rating and capacity table shown in Fig. 1. Also be sure new boiler is for
the type of gas being used. Check rating plate on right side of boiler.
The boiler must be supplied with correct type of gas, fresh air for combustion, and a suitable electrical supply. Boiler must also be connected to
a suitable venting system and an adequate piping system. Finally, a properly located thermostat is needed for control of heating system. If there
are any doubts as to the various requirements, check with local authorities and obtain professional help where needed. Take time to complete all
the steps for SAFE and PROPER operation of heating system.
→
If this boiler is installed in a building under construction, special care must be taken to insure a clean combustion air supply during the construction
process. Airborne particulates such as from drywall dust and from fiberglass insulation can clog the burner ports and cause incomplete combustion
and sooting.
Where required by authority having jurisdiction, the installation must conform to American Society of Mechanical Engineers Safety Code for
Controls and Safety Devices for Automatically Fired Boilers, No. CSD-1.
→
Before installing the boiler in the United States, refer to the current edition of the NFGC and the NFPA 90B. For copies of the NFGC and NFPA
90B, contact the National Fire Protection Association Inc., Batterymarch Park, Quincy, MA 02269; or for only the NFGC contact the American
Gas Association, 400 N. Capitol St., N.W., Washington DC 20001.
→
Before installing the boiler in Canada, refer to the NSCNGPIC. For a copy of the NSCNGPIC, contact Standard Sales, CSA International, 178
Rexdale Boulevard, Etobicoke (Toronto), Ontario, M9W 1R3, Canada.
→
Installation must comply with regulations of serving gas supplier and local building, heating, plumbing or other codes in effect in the area in which
installation is made. In absence of local building codes, installation must comply with NFGC in the United States and the NSCNGPIC in Canada.
The following steps are all necessary for proper installation and safe operation of boiler.
1. LOCATING THE BOILER
2. FRESH AIR FOR COMBUSTION
3. INSTALLATION—SYSTEM PIPING
4. CHIMNEY AND VENT PIPE CONNECTION
5. GAS SUPPLY PIPING
6. ELECTRICAL WIRING
7. CHECKING AND ADJUSTING
WARNING: Keep boiler area clean and free from combustible materials, gasoline, and other flammable vapors and
liquids. Failure to follow this warning could result in explosion, electrical shock, fire, personal injury, or death.
WARNING: Improper installation, adjustment, alteration, service, maintenance, or use can cause carbon monoxide
poisoning, explosion, fire, electrical shock, or other conditions which may cause personal injury or property damage.
Consult a qualified installer, service agency, local gas supplier, or your distributor or branch for information or assistance.
The qualified installer or agency must use only factory-authorized and listed kits or accessories when modifying this
product. Boilers with cast iron burners are not to be converted to propane. Failure to follow this warning could result in
electrical shock, fire, personal injury, or death.
NOTE: Installers—Follow local regulations with respect to installation of CO detectors. Follow maintenance recommendations in this instruction
manual.
N.B. Techniciens—Veuillez vous conformer à la réglementation en vigueur concernant l’ installation des détecteurs d’oxyde de carbone. Suivre
les consignes d’entretien figurant dans le manuel d’instruction ci-joint.
BOILER RATINGS AND CAPACITIES
The ratings marked "Net I=B=R Rating" indicate the amount of remaining heat input that can be used to heat the radiation or terminal units. The
→
Net I=B=R Ratings shown are based on an allowance of 1.15 in accordance with the factors in the I=B=R Standard as published by The Hydronics
Institute. New York City MEA Number 484-84-E-Vol. III.
Selection of boiler size should be based upon "Net I=B=R Rating" being equal to or greater than calculated heat loss of building.
Consult manufacturer before selecting a boiler for installations having unusual piping and pickup requirements.
These boilers must stand on a non-combustible floor. If installed on a combustible floor, a factory-approved combustible floor base must be used.
BOILERS FOR USE AT HIGH ALTITUDE
This boiler is factory equipped for use at altitudes of 0-2000 ft above sea level. For use at altitudes above 2000 ft above sea level, input ratings
are reduced by a change in main burner orifice size.
U.S.A. Only—For altitudes above 2000 ft above sea level, input ratings should be reduced at the rate of 4 percent for each 1000 ft above sea level.
→
Consult the NFGC or the manufacturer for correct orifice sizing information. High-altitude orifices are available from boiler manufacturer.
—3—
RELIEF
VALVE
PRESSURE
TEMP
GAGE
A
1 1⁄4″ SUPPLY
COMBINATION
LIMIT & RELAY
CONTROL
1 1⁄4″ RETURN
23 1⁄4″
VENT
CONNECTOR
BLOWER
29″
23″
25 1⁄4″
PRESSURE
SWITCH
5 5⁄8″ 5 5⁄8″
BURNER
1 3⁄4″
7″
GAS
VALVE
CIRCULATOR
INT. PILOT
CONTROL
LEFT SIDE RIGHT SIDEFRONT
A85084
Gas-Fired Hot Water Boilers
NATURAL AND PROPANE GAS† DIMENSIONS (IN.)
BOILER MODEL NUMBER*
BW3AAN000042ABAA 2 42.5 36 31 11 4
BW3AAN000075ABAA 3 75.0 63 55 14-1/4 4
BW3AAN000112ABAA 4 112.5 94 82 17-1/2 4
BW3AAN000150ABAA 5 150.0 125 109 20-3/4 4
BW3AAN000187ABAA 6 187.5 155 135 24 4
BW3AAN000225ABAA 7 225.0 186 162 27-1/4 4
* Sixth position of Model No. indicates natural or propane gas usage: N = Natural Gas
† Boilers are equipped for altitudes up to 2000 ft only.
U.S.A Only—For altitudes above 2000 ft, ratings should be reduced at the rate of 4 percent for each 1000 ft above sea level.
Canada Only—Boilers may be used at high altitude by using a certified field conversion kit, resulting in 10 percent derate.
Heating Capacity is based on Department of Energy (DOE) test procedure.
MBH—1000 Btuh (British Thermal Unit Per Hr)
Canada Only—For altitudes in the range of 2000-4500 ft above sea level, boilersmay be field equipped for use at high altitude by using a certified
NO. OF
SECTIONS
Fig. 1—Dimensional Drawing and Boiler Ratings and Capacities
A.G.A.
Input
MBH
P = Propane Gas
Heating
Capacity
MBH
Net
I=B=R
Rating
MBH
field conversion kit. The change in main burner orifice size results in boiler’s input rating being reduced by 10 percent. The conversion shall be
carried out by a manufacturer’s authorized representative in accordance with the requirements of manufacturer, provincial or territorial authorities
having jurisdiction, and in accordance with the requirements of the CAN/CGA-B149.1 and CAN/CGA-B149.2 Installation Codes. The certified
field conversion kit includes a conversion data plate which must be attached to boiler adjacent to rating plate indicating that boiler has been
converted for high-altitude use. The conversion data plate must be filled in with the correct conversion information.
→ LOCATING THE BOILER
NOTE: This unit MUST be set on a concrete or other non-combustible material base or floor.
1. Select level location as centralized with piping system and as near chimney as possible.
2. Place crated boiler at selected location. Remove crate by pulling crate sides from top and bottom boards. When boiler is to be installed on
a combustible floor, a combustible floor base must be used.
This boiler must NOT be installed on carpeting.
3. Boiler is to be level. Metal shims may be used under base legs for final leveling.
4. The floor supporting boiler must be non-combustible. If it is combustible, place the boiler on a factory-approved combustible floor base.
We use a 2-in. Cladlite™ pad as a combustible floor base. These are available from your local supplier. Use a minimum 24-in. X 30-in.
pad for 2-5 section boilers and a minimum 30-in. X 30-in. pad for 6-7 section boilers. The boiler must be centered on combustible floor
base.
5. Additional clearances for service may exceed clearances for fire protection. Always comply with the minimum fire protection clearances
shown on the unit. An 18-inch clearance should be maintained on any side where passage is required to access another side for cleaning,
servicing, inspecting or replacement of any part that may need attention. An 18-inch clearance is recommended on the control side for
servicing.
6. Determine boiler room size. Rooms that are large in comparison with the size of boiler are defined as rooms having a volume equal to or
greater than 16 times the volume of the boiler. Where room ceiling height is greater than 8 ft, volume of room shall be figured on the basis
of 8 ft ceiling height. Determination of room size should be based on total volume of all gas fired equipment installed in that room. (See
Table 1.) Refer to Section 6.3 of NFGC, Central Heating Boilers and Furnaces for further information, including approved methods for
reducing clearances in large rooms.
Width Vent Diameter
A
To Chimney
(Category I)
—4—
→ Table 1—Room Large In Comparison With Boiler
MINIMUM ROOM
BOILER SIZE
(SECTIONS)
2 4.3 68.7
3 5.6 89.0
4 6.8 109.3
5 8.1 129.5
6 9.4 149.8
7 10.6 170.1
* For room with single boiler only.
BOILER VOLUME
(CU FT)
VOLUME REQUIRED
TO BE LARGE
ROOM
(CU FT)*
Table 2—Minimum Clearances From Combustible Materials and For Servicing
ALCOVE OR ROOM
PART OF BOILER
Top 66
Rear 66
Control Side 86
Opposite Control Side 66
Front 18 18
Flue/Vent Connector 66
Boiler Piping 11
NOT LARGE
IN COMPARISON
WITH BOILER (IN.)
ROOM LARGE
IN COMPARISON
WITH BOILER (IN.)
7. Table 2 shows minimum clearances from combustible materials.
8. Equipment shall be installed in a location in which the facilities for ventilation permit satisfactory combustion of gas, proper venting, and
maintenance of ambient temperature at safe limits under normal conditions of use. Equipment shall be located so as not to interfere with
proper circulation of air. When normal infiltration does not provide necessary air, outside air shall be introduced as described in Fresh Air
for Combustion section.
9. Advise owner to keep air passages free of obstructions. Ventilation and combustion air must enter boiler room without restrictions.
10. The boiler shall be installed such that the automatic gas ignition system components are protected from water (dripping, spraying, rain , etc.)
during appliance operation and service (condensate trap, control replacement, etc.).
→FRESH AIR FOR COMBUSTION
Provision for combustion and ventilation air must be in accordance with Section 5.3 of NFGC, Air for Combustion and Ventilation, or applicable
provisions of local building codes.
Canadian installations must be installed in accordance with NSCNGPIC and all authorities having jurisdiction.
WARNING: Be sure to provide enough fresh air for combustion. Enough air ensures proper combustion and
ASSURES THAT NO HAZARD WILL DEVELOP DUE TO LACK OF OXYGEN. Failure to follow this warning can cause a fire,
personal injury, or death.
You must provide for enough fresh air to assure proper combustion. The fire in the boiler uses oxygen. It must have a continuous supply. The air
in a house contains only enough oxygen to supply the burner for a short time. Outside air must enter the house to replace the oxygen used by the
burner. Study the following examples to determine your fresh air requirements.
CAUTION: Air for combustion must not be contaminated by halogen compounds, which include fluoride, chloride,
bromide, and iodide. These elements are found in aerosol sprays, detergents, bleaches, cleaning solvents, salts, air
fresheners, and other household products. Excessive exposure to contaminated combustion air will result in safety and
performances related problems.
CAUTION: If a fireplace or a kitchen or bathroom exhaust fan is used, an outside air intake should be installed. These
devices rob the boiler and water heater of combustion air.
PROCEDURE 1—BOILER LOCATED IN UNCONFINED SPACE
EXAMPLE 1:
An unconfined space is defined as a space whose volume is not less than 50 cubic feet per 1,000 Btu per hour of the total input rating of all
appliances installed in that space.
If your boiler is in an open area (unpartitioned basement) in a conventional house, the air that leaks through the cracks around doors and windows
will usually be adequate to provide air for combustion. The doors should not fit tightly. Do not caulk the cracks around the windows.
—5—
Equipment located in buildings of unusually tight construction shall be provided with air for combustion, ventilation, and dilution of flue gases
using the methods described in example 2B or shall be specially engineered. The authority having jurisdiction must approve specially engineered
installations.
PROCEDURE 2—BOILER LOCATED IN CONFINED SPACE
EXAMPLE 2A: ALL AIR FROM INSIDE THE BUILDING
The confined space shall be provided with two permanent openings communicating directly with an additional room(s) of sufficient volume so
that the combined volume of all spaces meets the criteria for an unconfined space. The total input of all gas utilization equipment installed in the
combined space shall be considered in making this determination. Each opening shall have a minimum free area of one square inch per 1,000 Btu
per hour of the total input rating of all gas utilization equipment in the confined space, but not less than 100 square inches. One opening shall be
within 12 inches of the top and one within 12 inches of the bottom of the enclosure. The minimum dimension of air openings shall not be less
than 3 inches.
EXAMPLE 2B: ALL AIR FROM OUTDOORS
The confined space shall communicate with the outdoors in accordance with examples 1 or 2. The minimum dimension of air openings shall not
be less than 3 in. Where ducts are used, they shall be of the same cross-sectional area as the free area of the openings to which they connect.
1. Two permanent openings, one commencing within 12 inches of the top, and one commencing within 12 inches of the bottom of the
enclosure shall be provided. The openings shall communicate directly, or by the ducts,with the outdoors or spaces (crawl or attic) that freely
communicate with the outdoors
a. Where directlycommunicating with the outdoors or where communicatingto the outdoors through vertical ducts, eachopening shall have
a minimum free area of 1 sq. in. per 4000 Btu per hour of total input rating of all equipment in the enclosure. (See Table 3A.)
b. Where communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 sq. in. per 2000
Btu per hour of total input rating of all equipment in the enclosure. (See Table 3B.)
2. One permanent opening commencing with 12 inches of the top of the enclosure shall be permitted where the equipment has clearance of
at least 1 inch from the sides and back and 6 inches from the front of the appliance. The opening shall directly communicate with the
outdoors or shall communicate through a vertical or horizontal duct to the outdoors or spaces (crawl or attic) that freely communicate with
the outdoors and shall have a minimum free area of:
a. 1 sq. inch per 3000 Btu per hour of the total input of all equipment located in the enclosure (see Table 3C), and
b. Not less than the sum of the areas of all vent connectors in the confined space.
Table 3A—Fresh Air Duct Capacities for Vertical Ducts (Btuh)*
100% FREE AREA 75% FREE AREA 25% FREE AREA
Fresh Air
Duct Size (In.)
3" X 12" 144,000 108,000 36,000
8"X8" 256,000 192,000 64,000
8" X 12" 384,000 288,000 96,000
8-1/2" X 16" 512,000 384,000 128,000
* 1 Square Inch per 4,000 Btuh
1/4-in. Mesh
Screen
Metal
Louvers
Wood
Louvers
Fresh Air
Duct Size (In.)
3" X 12" 72,000 54,000 18,000
8"X8" 128,000 96,000 32,000
8" X 12" 192,000 144,000 48,000
8-1/2" X 16" 256,000 192,000 64,000
* 1 Square Inch per 2,000 Btuh
Fresh Air
Duct Size (In.)
3" X 12" 108,000 81,000 27,000
8"X8" 192,000 144,000 48,000
8" X 12" 288,000 216,000 72,000
8-1/2" X 16" 384,000 288,000 96,000
* 1 Square Inch per 3,000 Btuh
Table 3B—Fresh Air Duct Capacities for Horizontal Ducts (Btuh)*
100% FREE AREA 75% FREE AREA 25% FREE AREA
1/4-in. Mesh
Screen
Metal
Louvers
Table 3C—Fresh Air Duct Capacities for Vertical or Horizontal Ducts (Btuh)*
100% FREE AREA 75% FREE AREA 25% FREE AREA
1/4-in. Mesh
Screen
Metal
Louvers
—6—
Wood
Louvers
Wood
Louvers
INSTALLATION—SYSTEM PIPING
1. Place boiler in selected location (as close to chimney as possible). Boiler is shipped assembled. Only the relief valve with a drain line to
carry any water to a drain and a drain valve need to be installed.
2. Install relief valve on 3/4-in. pipe nipple in tapped opening in left end section. Connect a drain line of same pipe size (3/4 in.) to carry any
water away to a drain. No shutoff of any description shall be placed between safety relief valve and boiler, or on discharge pipes between
such safety valves and the atmosphere. Installation of safety relief valve shall conform to the requirements of the ANSI/ASME Boiler and
Pressure Vessel Code, Section IV.
3. Install drain valve on lower left side of boiler as marked.
4. Connect supply and return lines to boiler. The connections may require certain additional fittings and parts. (See Fig. 2 and 4.)
ELECTRIC
ZONE
VALVES
TO ZONE 1
SUPPLY MAIN
RETURN
LINE
AIR VENT
AIR
PURGER
FILTROL
TANK
LIMIT
CONTROL
A96140
COLD WATER
RELIEF
VALVE
AIR VENT
INLET
SUPPLY
MAIN
AIR
GAUGE
RETURN
LINE
PURGER
FILTROL
TANK
LIMIT
CONTROL
Fig. 2—Forced Hot Water Typical Piping
A95176
COLD
WATER
RELIEF
VALVE
TO ZONE
2 SUPPLY
MAIN
INLET
GAUGE
Fig. 3—Forced Hot Water Typical Piping with
Zone Control Valves
If installing an entire new heating system, first install all radiation units (panels, radiators, or cabinets) and supply and return mains, then make
connections at boiler.
In connecting cold water supply to water valve, make sure that a clean water supply is available. When water supply is from a well or pump, a
sand strainer should be installed at pump.
A hot water boiler installedabove radiation level must be equipped witha low water cut-off device. A periodicinspection is necessary as is flushing
of float-type devices per the manufacturer’s specific instructions.
PROCEDURE 1—FOR USE WITH COOLING UNITS
When this boiler is used in connection with refrigeration systems,it shall be installed so thatthe chilled medium is piped in parallel with the heating
boiler. Appropriate valves must be used to prevent the chilled medium from entering the heating boiler. (See Fig. 4.)
When this boiler is connected to heating coils located in air handling units where they may be exposed to refrigerated air circulation, the piping
system shall be equipped with flow control valves or other automatic means to prevent gravity circulation of boiler water during cooling cycles.
PROCEDURE 2—LOW DESIGN WATER TEMPERATURE SYSTEMS (BELOW 140°F)
If boiler is to be used in a heating system where design water temperatures below 140°F are desired (for example radiant floor heating), a 3-way
or 4-way mixing valve or suitable alternative is required to prevent low temperature return water from entering boiler. Follow mixing valve
manufacturer’s Installation Instructions.
The minimum design return water temperature to boiler to prevent condensation in boiler and venting system is 120°F. The minimum high limit
setting is 140°F.
CHIMNEY AND VENT PIPE CONNECTION
For boilers with connections to gas vents or chimneys, vent installations shall be in accordance with Part 7 NFGC, Venting of Equipment, in the
United States or Part 7 NSCNGPIC, Venting System and Air Supply for Appliances in Canada, and applicable provisions of local building codes.
PROCEDURE 1—CHECKING CHIMNEY
The chimney is a very important part of the heating system. It must be clean, the right size, properly constructed, and in GOOD CONDITION.
No boiler can function properly with a bad chimney.
1. Use local codes for installation or NFGC. In Canada, follow CAN/CGA-B149.1 or .2 Installation Codes. It is very important to properly
size the venting system for induced draft appliances. Consult the Vent Sizing Tables in Part 11 of the NFGC in the United States for correct
sizing information. In Canada, consult the Vent Sizing Tables in Appendix B of the NSCNGPIC.
—7—
TO SYSTEM
A
B
C
D
WATER
CHILLER
VALVES C & D
CLOSE FOR HEATING;
OPEN FOR COOLING
VALVES A & B
OPEN FOR HEATING;
CLOSE FOR COOLING
A96141
Fig. 4—Piping Arrangements for Boiler Used in Connection with Refrigeration System
2. The boiler’s induced draft blower has a 3-in. outlet. A 3-in. X 4-in. increaser fitting is included in the parts bag. Locate increaser fitting
on outlet of induced draft blower and secure gastight with a bead of the factory-supplied silicone sealant. The increaser fitting is required
on this boiler for Category I venting, and 4 in. is the minimum permissible vent diameter. This does NOT imply that the vent connector
is intended to be 4-in. diameter pipe. The vent connector shall be sized according to the appropriate NFGC venting tables in the U.S.A. or
the NSCNGPIC in Canada, and may be required to be larger than 4-in. diameter.
NOTE: The boiler installation for chimney venting is not complete unless the 3-in. X 4-in. increaser fitting is located and secured.
3. These are energy-efficient boilers with a low stack or exhaust temperature.
4. If venting into masonry chimney without a liner, line chimney from top to bottom with either:
a. listed Type-B vent pipe
b. listed flexible vent liner
c. poured ceramic liner
5. Outside chimneys should not be used unless they are either:
a. enclosed in a chase
b. lined with Type-B vent pipe, listed flexible vent liner, or other certified chimney lining system
6. The vent connector from boiler to chimney should run as directly as possible with as few elbows as possible.
7. Where possible, it is recommended to common vent water heater and boiler. Consult the appropriate Vent Sizing Tables in either the NFGC
or NSCNGPIC for specific requirements of multiple appliance venting.
8. If boiler is the only appliance connected to vent, Type-B vent pipe is recommended for vent connector.
9. Slope pipe up from boiler to chimney not less than 1/4 in. per ft.
10. End of vent pipe must be flush with inside face of chimney flue. Use a sealed-in thimble for chimney connection.
11. The sections of vent pipe should be fastened with at least 3 sheet metal screws to make piping rigid. Use stovepipe wires to support pipe
from above.
12. Do not connect to fireplace flue.
13. Do not install a damper on this boiler.
PROCEDURE 2—MINIMUM VENT PIPE CLEARANCE
If vent pipe must go through a crawlspace, Type-B vent pipe should be used. Where vent pipe passes through a combustible wall or partition, use
a ventilated metal thimble. The thimble should be 4 in. larger in diameter than vent pipe.
If boiler is installed with single-wall vent, it must have a 6-in. clearance between its surface and any combustible material.
A new Type-B gas vent or flexible liner must be installed in accordance with instructions furnished with vent. Maintain clearances as specified
for vent pipe.
Check vent pipe to see if it is firestopped where it goes through floor or ceiling. It should have an approved vent cap with clearances from roof
shown in Fig. 5. If clearances are less than shown in Fig. 5, have vent checked by local authorities.
—8—
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