Crown Boiler BSI SERIES Service manual

DESIGNED TO LEAD
980433 Rev 11 - 3/23
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage, injury, or
loss of life. For assistance or additional information, consult a qualified installer, service agency or the gas
supplier. This boiler requires a special venting system. Read these instructions carefully before installing.
!
BSI Series
Gas-Fired Natural Draft Steam Boilers
INSTALLATION, OPERATING and SERVICE
INSTRUCTIONS
TO THE INSTALLER:
Affix these instructions on or adjacent to boiler.
Provide model number and serial number when
seeking information and support.
TO THE CONSUMER:
Retain these instructions for future reference.
Contact heating contractor for all issues and support.
9902339
H
Models:
• BSI069
• BSI103
• BSI138
• BSI172
• BSI207
• BSI241
• BSI276
PROTECT YOUR INVESTMENT
REGISTER YOUR WARRANTY AT
VELOCITYBOILERWORKS.COM

The following terms are used throughout this manual to bring attention to the presence of hazards of various
risk levels, or to important information concerning product life.
The Massachusetts Board of Plumbers and Gas Fitters has approved these boilers. See the Massachusetts Board of
Plumbers and Gas Fitters website for the latest Approval Code or ask your local Sales Representative.
The Commonwealth of Massachusetts requires this product to be installed by a licensed Plumber or Gas fitter.
DANGER
Explosion Hazard. DO NOT store or use gasoline or other flammable vapors or liquids in the vicinity of
this or any other appliance.
If you smell gas vapors, DO NOT try to operate any appliance - DO NOT touch any electrical switch or
use any phone in the building. Immediately, call the gas supplier from a remotely located phone.
Follow the gas supplier’s instructions or if the supplier is unavailable, contact the fire department.
!
NOTICE: Indicates special instructions on
installation, operation, or maintenance which
are important but not related to personal injury
hazards.
DANGER
Indicates an imminently hazardous situation
that, if not avoided, will result in death or serious
injury.
CAUTION
Indicates a potentially hazardous situation
that, if not avoided, may result in moderate or
minor injury or property damage.
WARNING
Indicates a potentially hazardous situation
that, if not avoided, could result in death or
serious injury.
! !
!
WARNING
This boiler must only be serviced and repaired by skilled and experienced service technicians.
• If any controls are replaced, they must be replaced with identical models.
• Read, understand and follow all the instructions and warnings contained in all the sections of this
manual.
• If any electrical wires are disconnected during service, clearly label the wires and assure that the wires
are reconnected properly.
• Never jump out or bypass any safety or operating control or component of this boiler.
• Assure that all safety and operating controls and components are operating properly before placing
the boiler back in service.
!

WARNING
Asphyxiation Hazard. Fire Hazard. Explosion Hazard. This boiler requires regular maintenance and
service to operate safely. Follow the instructions contained in this manual.
• Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal
injury or loss of life. Read and understand the entire manual before attempting installation, start-up
operation, or service. Installation and service must be performed only by an experienced, skilled, and
knowledgeable installer or service agency.
• This boiler must be properly vented.
• This boiler needs fresh air for safe operation and must be installed so there are provisions for adequate
combustion and ventilation air.
• Asphyxiation Hazard. The interior of the venting system must be inspected and cleaned before the
start of the heating season and should be inspected periodically throughout the heating season.
A clean and unobstructed venting system is necessary to allow noxious fumes that could
cause injury or loss of life to vent safely and will contribute toward maintaining the boiler’s efficiency.
• Installation is not complete unless a safety relief valve is installed in the supply piping. - See the Water
Piping Section of this manual for details.
• This boiler is supplied with safety devices which may cause the boiler to shut down and not re-start
without service. If damage due to frozen pipes is a possibility, the heating system should not be left
unattended in cold weather; or appropriate safeguards and alarms should be installed on the heating
system to prevent damage if the boiler is inoperative.
• Do not obstruct the combustion or ventilation air supply to the boiler.
• Burn Hazard. This boiler contains very hot water under high pressure. Do not unscrew any pipe fittings
nor attempt to disconnect any components of this boiler without positively assuring the water is cool
and has no pressure. Always wear protective clothing and equipment when installing, starting up or
servicing this boiler to prevent scald injuries. Do not rely on the pressure and temperature gauges to
determine the temperature and pressure of the boiler. This boiler contains components which become
very hot when the boiler is operating. Do not touch any components unless they are cool.
• Respiratory Hazard. Boiler materials of construction, products of combustion and the fuel contain
alumina, silica, heavy metals, carbon monoxide, nitrogen oxides, aldehydes and/or other toxic or
harmful substances which can cause death or serious injury and which are known to the state of
California to cause cancer, birth defects and other reproductive harm. Always use proper safety
clothing, respirators and equipment when servicing or working nearby the appliance.
• Failure to follow all instructions in the proper order can cause personal injury or death. Read all
instructions, including all those contained in component manufacturers manuals which are provided
with the boiler before installing, starting up, operating, maintaining or servicing.
• All cover plates, enclosures and guards must be in place at all times.
DANGER
Explosion Hazard. Electrical Shock Hazard. Burn Hazard. This boiler uses flammable gas, high voltage
electricity, moving parts, and very hot water under high pressure.
Assure that all gas and electric power supplies are off and that the water temperature is cool before attempting
any disassembly or service. Do not attempt any service work if gas is present in the air in the vicinity of the
boiler. Never modify, remove or tamper with any control device.
!
!

Table of Contents
I. Product Description ............................................................................... 1
II. Specications ......................................................................................... 1
III. Pre-Installation .................................................................................... 2
IV. Locating the Boiler ................................................................................ 3
V. Air for Combustion & Ventilation ......................................................... 4
VI. Venting ................................................................................................... 8
VII. Steam Piping .......................................................................................... 11
VIII. Indirect Water Heater Piping ................................................................. 16
IX. Gas Piping ............................................................................................ 17
X. Wiring .................................................................................................... 19
XI. Start-Up & Checkout ............................................................................. 23
XII. Operation ............................................................................................... 29
XIII. Service & Maintenance .......................................................................... 30
XIV. Troubleshooting ..................................................................................... 34
XV. Parts ........................................................................................................ 38
Appendix A .......................................................................................................44

1
1
I Product Description
The BSI series boilers are low pressure cast iron gas red steam boilers designed for use in closed steam heating systems
at steam pressures below 15psi. These boilers are Category I draft diverter equipped appliances, which must be vented by
natural draft using a lined masonry or listed metal chimney system. An adequate supply of air for combustion, ventilation and
dilution of ue gases must be available in the boiler room. These boilers are not designed for use in process or other “open”
steam systems.
II Specications
TABLE 2.2: BSI SPECIFICATIONS
FIGURE 2.1: BSI BOILERS - GENERAL CONFIGURATION
BSI SPACE HEATING RATINGS
NATURAL AND LP GAS
NO. OF
SEC.
DIMENSIONS
WATER
VOLUME
(Gal.)
CROWN
MODEL
NUMBER
INPUT
(MBH)
HEATING
CAPACITY
(MBH)
AHRI NET RATING STEAM
(MBH) AFUE
(%)
“A”
(in)
“B”
(in)
“C”
(in)
“D”
(in)
SQ. FT. MBH
BSI069 69 57 179 43 82.0 3 12-3/4 28 40-7/16 4 5.1
BSI103 103 85 267 64 82.0 4 16 28 40-7/16 5 6.5
BSI138 138 113 354 85 82.0 5 19-1/4 28 40-7/16 6 7.9
BSI172 172 142 446 107 82.1 6 22-1/2 28 40-7/16 6 9.3
BSI207 207 171 533 128 82.1 7 25-3/4 30 40-7/16 7 10.7
BSI241 † 241 199 621 149 82.2 8 29 30 40-7/16 7 12.1
BSI276 † 276 229 717 172 82.2 9 32-1/4 30 40-7/16 8 13.5
1. Not for use at altitudes above 2,000 ft. in natural or LP gas.
†Available as semi-packaged boiler.

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2
III Pre-Installation
1) Inspect shipment carefully for signs of damage. Any claim for damage or shortage in shipment must be led immediately
against carrier by consignee. No claims for variances or shortages will be allowed by Boiler Manufacturer, unless presented
within sixty (60) days after receipt of equipment.
2) Safe, reliable operation of this boiler depends upon installation by a professional heating contractor in strict accordance with
this manual and the requirements of the authority having jurisdiction.
• In the absence of an authority having jurisdiction, installation must be in accordance with this manual and the
National Fuel Gas Code, ANSI Z223.1-latest edition. In Canada, follow CAN/CSA B149.1 (Natural Gas and
Propane Installation Code).
• Where required by the authority having jurisdiction, this installation must conform to the Standard for Controls and
Safety Devices for Automatically Fired Boilers (ANSI/ASME CSD-1)-latest edition.
3) Make sure that a properly sized chimney is available which is in good condition. Consult the authority having jurisdiction,
Part VI of this manual, and the National Fuel Gas Code for additional information on venting requirements.
4) Make sure the boiler is properly sized. A steam boiler must be sized to match the amount of connected radiation. If the
boiler is undersized for the connected radiations, radiators furthest from the boiler will remain cold, resulting in uneven
heat. This will happen even if the output of the boiler matches the design heat loss of the structure. Conversely, a boiler
that is too large for the connected radiation will short cycle on pressure, resulting in inecient operation. Determine
the boiler size required for the connected radiation using a reference such as the I=B=R Residential Hydronic Heating
Guide (Pub. RHH) published by Air Conditioning Contractors of America (ACCA).
5) Make sure that the boiler received is congured for the correct gas (natural or LP).
6) This boiler is not congured for installation at altitudes above 2000ft.
WARNING
Carefully read all instructions before installing boiler. Failure to follow all instructions in proper order can cause
personal injury or death.
!
DANGER
• Do not attempt to operate a natural gas boiler on LP, or an LP boiler on natural gas without first converting
it using a kit provided by the factory.
• Failure to properly convert this boiler for the fuel being used will result in operation of the boiler at
high Carbon Monoxide (CO) levels and/or other unsafe conditions, resulting in personal injury or loss of
life. Improper conversion may also result in unreliable operation and severe property damage.
!

3
3
IV Locating the Boiler
1) Clearances:
• Observe minimum clearances shown below to avoid potential re hazard. Except as noted, these clearances apply to all
combustible construction as well as noncombustible walls, ceilings and doors. Also see Figure 4.1.
Front - Alcove Left Side - 6” Right Side - 18”
Rear - 6” Top - 17”
• A 24” service clearance from the jacket is recommended on the left, right, and front of the boiler. These clearances may
be reduced to those shown in Figure 4.1, however servicing the boiler will become increasingly dicult as these service
clearances are reduced.
• If the right side 24” service clearance is reduced, adequate clearance must be maintained to easily read and access the
controls. Alternatively, access may be provided using a door.
2) The boiler must be installed on a hard level surface. This surface may be combustible.
3) Do not install this boiler in a location where gasoline or other ammable vapors or liquids, or sources of hydrocarbons (i.e.
bleaches, cleaners, chemicals, sprays, paint removers, fabric softeners, etc.) are used or stored.
4) Do not install this boiler in an area where large amounts of airborne dust will be present, such as a workshop.
5) The boiler should be located as close to the chimney as possible.
6) Do not install this boiler over carpeting. This may cause a re.
7) Do not install this boiler directly on a surface that may get wet. Raise the boiler on a pad.
8) Protect ignition system components from sources of water that may spray, drip or rain on them during installation or service.
9) For basement installation provide concrete base if oor is not level or if water may be encountered on oor around boiler.
WARNING
Failure to observe the following location requirements could result in a fire, explosion or Carbon Monoxide (CO)
hazard.
!
FIGURE 4.1: CLEARANCES TO COMBUSTIBLE CONSTRUCTION AND NONCOMBUSTIBLE CEILINGS,
WALLS, AND DOORS.

4
4
V Air for Combustion and Ventilation
Sucient fresh air must be supplied for combustion, ventilation, and ue gas dilution. Provisions for an adequate fresh air
supply must be made in accordance with local codes, or in the absence of such codes, the National Fuel Gas Code (NFPA 54/
ANSI Z223.1). In Canada, refer to the Natural Gas and Propane Installation Code (CAN/CSA 149.1).
The National Fuel Gas Code describes three basic ways to supply this boiler with adequate fresh air:
Indoor Combustion Air – Combustion air is drawn into the boiler room from other parts of the building and from the outdoors
through natural inltration (cracks under doors, etc). This method can not be used in all cases – see discussion below.
Outdoor Combustion Air – Combustion air is brought directly into the boiler room from outdoors through ducts or grills sized
and installed specically for this purpose.
Mechanical Combustion Air Supply – Combustion air is brought into the room from outdoors using a blower system that is
engineered specically for this purpose.
Each of the above methods is described in more detail in the following sections. The National Fuel Gas Code also describes
some acceptable variations on these techniques that do not appear here.
Using the Indoor Combustion Air Method
1) Total the input of all appliances in the boiler room in thousands of BTU/hr.
2) Find the volume of the boiler room in cubic feet:
Volume (ft3) = Length (ft) x Width (ft) x Height (ft)
If the boiler room adjoins another room and there is no door present between these two rooms, add the volumes of the
rooms together. Repeat for any other connected rooms which do not have doors. Do not add the volume of two rooms
separated by a door even if that door is “always left open”.
3) Divide the volume obtained in Step 2 by the input calculated in Step 1.
4) If the result is at least 50 ft3 per 1000BTU/hr, and neither of the conditions described in (6) below are met, normal inl-
tration should provide adequate fresh air into the boiler room.
5) If the result is less than 50 ft3 per 1000BTU/hr, provide two openings into the boiler room, one near the oor and one
near the ceiling. The top edge of the upper opening must be within 6” of the ceiling and the bottom edge of the lower
opening must be within 6” of the oor (Figure 5.1):
• Each opening must have a free area of 1 square inch per 1000 BTU/hr input of all gas burning appliances in the
boiler room. The minimum opening dimension is 3 inches. Minimum opening free area is 100 square inches per
opening.
• If the total volume of both the boiler room and the room to which the openings connect is less than 50 cubic feet
WARNING
• This boiler is not designed for use in a space that is depressurized relative to the outdoors. Operating this
boiler in a depressurized space may cause severe personal injury or death.
• INSUFFICIENT COMBUSTION AIR SUPPLY may result in the production and release of deadly Carbon
Monoxide (CO) into the home.
• PROVIDE ENOUGH AIR to ventilate the boiler room, and sustain combustion. Ignition failure, overheating,
fire, carbon monoxide, and spillage of flue gases may result from poor air supply.
• Do not install this boiler in areas where it will draw combustion air from areas where chemicals, such as
bleaches, fabric softeners, paints, cleaners, refrigerants, and cat boxes are used or stored. Do not draw
combustion air containing large amounts of dust such as that generated by dry wall construction or
woodworking. Failure to observe this warning could result in objectionable odors, severe boiler damage,
personal injury or loss of life.
!

5
5
per 1000 BTU/hr of total appliance input, install a pair of identical openings into a third room. Connect additional
rooms with openings until the total volume of all rooms is at least 50 cubic feet per 1000 BTU/hr of input.
• The “free area” of an opening takes into account the blocking eect of mesh, grills, and louvers. Where screens are
used, they must be no ner than ¼” (4 x 4) mesh.
• If providing openings into adjacent rooms is undesirable, use the Outdoor Combustion Air Method.
6) Do not use the Indoor Combustion Air Method described above if either of the following are true:
a. The indoor space is so tightly constructed that the number of air changes per hour is known to be 0.4 or less.
b. The boiler room is depressurized relative to the outdoors. This depressurization is possible if the structure is
tightly constructed and/or is equipped with exhaust fans.
Example:
A 103MBH input boiler and a water heater are to be installed in a room measuring 6 ft - 3 in x 7 ft with an 8 ft
ceiling. The water heater has an input of 30000 BTU/hr:
Total input in thousands of BTU/hr = (103000 BTU/hr + 30000 BTU/hr) ÷ 1000 = 133
Volume of room = 6.25 ft x 7 ft x 8 ft = 350 ft3
350÷135 = 2.59. Since 2.59 is less than 50, there will be an inadequate fresh air supply in the boiler room un-
less openings are installed between the boiler room and at least one adjacent room. It turns out that the boiler room
in this example is adjacent to a full basement which is 20ft x 45ft x 8ft high. If two openings are installed into this
basement that each have a free area of 135in2, the combined volume of the boiler room and basement will be:
350ft3+ 6400ft3 = 6750ft3 and:
6750÷133 = 50.8ft3per 1000 BTU/hr.
In the absence of one of the conditions described in (6) above, this arrangement should provide an adequate fresh
air supply to all the appliances in the boiler room.
6” MAX
6” MAX
FIGURE 5.1: INDOOR COMBUSTION AIR METHOD

6
6
Using the Outdoor Combustion Air Method
1) Openings must be installed between the boiler room and the outdoors or a ventilated space, such as an attic or crawl
space, which communicates directly with the outdoors.
2) Two openings are required. The top edge of the upper opening must be within 6 inches of the ceiling. The bottom edge
of the lower opening must be within 6 inches of the oor.
3) Size openings and ducts as follows:
• Vertical ducts or openings directly outdoors (Figure 5.2, Figure 5.3, and Figure 5.4) - Each opening must have a free
cross sectional area of 1 square inch per 4000 BTU/hr of the total input of all gas-red appliances in the boiler room.
Minimum opening size is 3 inches.
• Openings to outdoors via horizontal ducts (Figure 5.5) - Each opening must have a free cross sectional area of 1
square inch per 2000 BTU/hr of the total input of all gas red appliances in the boiler room. Minimum opening size
is 3 inches.
FIGURE 5.2: ALL AIR FROM OUTDOORS, VENTILATED CRAWL SPACE AND ATTIC
FIGURE 5.3: ALL AIR FROM OUTDOORS, VIA VENTILATED ATTIC
6”

7
7
• The “free area” of an opening takes into account the blocking eect of mesh, grills, and louvers. Where screens are
used, they must be no ner than ¼” (4 x 4) mesh.
• If motorized louvers are installed in the openings to the outdoors, they must be interlocked to prevent operation of
the fuel burning appliances in the boiler room unless the louvers are open.
Mechanical Combustion Air Supply
A mechanical system may be used to bring all combustion air to the boiler which meets all of the following requirements:
1) The system must be manufactured specically for this purpose.
2) Size the system to deliver combustion air at the rate prescribed by the system manufacturer’s instructions, but no less
than 0.35 CFM for each 1000 BTU/hr of the combined input of all fuel burning appliances in the boiler room. If
exhaust fans are present within the building, additional capacity may be required to prevent the boiler room from being
depressurized.
3) The system must be interlocked to prevent operation of the fuel burning appliances in the boiler room if the system is not
operating.
6” MA X
6” MA X
FIGURE 5.4: OUTDOOR COMBUSTION AIR METHOD: USING OPENINGS INTO BOILER ROOM
6” M AX
6” M AX
FIGURE 5.5: OUTDOOR COMBUSTION AIR METHOD: USING HORIZONTAL DUCTS INTO BOILER ROOM

8
8
VI Venting
The vent system installation must be in accordance with local codes, or in the absence of such codes, the National Fuel Gas
Code (NFPA 54/ANSI Z223.1).
A typical vent installation is illustrated by Figure 6.1. The components of vent installation are boiler draft diverter, vent
damper, vent connector and chimney. This boiler is equipped with a draft hood which is built into the boiler; do not attempt to
install an external draft hood.
1) Acceptable Chimneys - The following chimneys may be used to vent this boiler:
• Listed Type B or L gas vent - Install in accordance with the manufacturer’s instructions, the terms of its listing, and
applicable codes.
• Masonry Chimney - The masonry chimney must be constructed in accordance with local codes, or in the absence of
any, the Standard for Chimneys, Fireplaces, Vents, and Solid Fuel Burning Appliances (NFPA 211). The chimney
must be lined with a clay liner or other listed lining system. Do not vent this boiler into an unlined chimney.
2) Acceptable Vent Connectors - The following may be used for vent connectors:
• Listed type B or L Gas Vent
• Single Wall Galvanized Pipe - Use 0.018” (26 gauge or heavier). The size and location of the chimney may not
permit the use of a single wall connector in some cases. (see the National Fuel Gas Code). Do not use single wall
pipe for vent connectors in attics.
• Other Vent Connectors Permitted by the National Fuel Gas Code.
3) Chimney and Vent Connector Sizing - Size the chimney and vent connector in accordance with the National Fuel Gas
Code.
WARNING
• Improper venting may result in property damage and/or the release of flue gases, which contain deadly
Carbon Monoxide (CO), into the home, which can cause severe personal injury or death.
• Do not use plastic venting materials (such as CPVC, PVC and RADEL) to vent this boiler.
• Inspect existing chimney before installing boiler. Failure to clean or replace damaged pipe or tile lining will
cause severe injury or death.
!
FIGURE 6.1: TYPICAL VENT SYSTEM INSTALLATION AND COMPONENTS

9
9
RIGHT SIDE VIEW
4) Exterior Chimneys - An exterior chimney has one or more sides exposed to the outdoors below the roof line. The
National Fuel Gas Code prescribes two conditions under which an exterior chimney may be used:
• In some very restrictive cases, this boiler may be vented into an exterior ceramic lined masonry chimney. See the
National Fuel Gas Code for information on when exterior chimneys may be used.
• An exterior masonry chimney may be used if it is lined with B vent or a listed chimney lining system.
5) This boiler may be vented using a listed power venter. The power venter must be in sized and installed in accordance
with the power venter manufacturer’s instructions, the terms of the power venter listing, and applicable codes. The boiler
must be electrically interlocked with the power venter to prevent boiler operation if the power venter fails to operate.
Before deciding to use a power venter, make certain that the ue gas exiting the power venter will not damage adjacent
construction or other structures. Also make certain that the power venter terminal will not be subjected to winds which
could aect power venter operation.
6) Do not connect the vent of this appliance into any portion of a mechanical vent system operating under positive pressure.
7) Do not connect the boiler into a chimney ue serving an open replace or other solid fuel appliance.
8) Prior to boiler installation, inspect chimney for obstructions or other defects and correct as required. Clean chimney as
necessary.
9) Vent pipe should slope upward from draft diverter not less than one inch in four feet. No portion of vent pipe should run
downward or have sags. Vent pipe must be securely supported.
10) The vertical section of vent pipe coming o the boiler should be as tall as possible, while still maintaining the proper
clearance from the horizontal vent connector to combustibles and the proper pitch called for in (9) above.
11) Vent pipe should be installed above the bottom of the chimney to prevent blockage.
12) Vent pipe must be inserted ush with inside face of the chimney liner and the space between vent pipe and chimney
sealed tight.
13) Do not install the vent damper in any portion of the vent system which is used by appliances other than the boiler being
installed.
14) Installation of the vent damper supplied with this boiler is mandatory. Install vent damper (see Figure 6.2) as follows:
a) Open vent damper carton and remove installation instructions. Read the instructions thoroughly before proceeding.
Verify that vent damper is same size as draft diverter outlet (Figure 2.1). Unpack vent damper carefully. Do not
force closed damper blade. Forcing vent damper closed may result in damaged gear train and void warranty.
b) Vent damper is factory shipped having approximately ¾” diameter hole in the vent damper blade, which must be
plugged. Use the plug supplied with the damper.
c) Mount the vent damper on the ue collar without modication to either and secure with sheet metal screws. Make
sure screws do not interfere with damper blade operation. Vent damper blade position indicator must be visible to
users.
d) The damper wire harness is shipped pre-wired into the boiler. Plug the loose end of this harness into the damper and
secure the exible conduit to the damper using a connector nut provided.
Provide adequate clearance to combustible construction and servicing.
e) Install vent connector pipe and vent ttings from vent damper outlet to chimney or gas vent. Secure with sheet metal
screws and support as required.
FIGURE 6.2: VENT DAMPER INSTALLATION DETAILS

10
10
Removing an Existing Boiler from a Common Chimney
In some cases, when an existing boiler is removed from a common chimney, the common venting system may be too large
for the remaining appliances. 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 opening in the common venting system.
b) Visually inspect the venting system for proper size and horizontal pitch and determine there is no blockage or
restriction, leakage, corrosion and other deciencies which could cause an unsafe condition.
c) Insofar as practical, close all building doors and windows and all doors between the space in which all 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
replace dampers.
d) Place in operation the appliance being inspected. Follow the lighting instructions. Adjust thermostat so the appliance
will operate continuously.
e) Test for spillage at the draft hood relief opening after ve (5) minutes of main burner operation. Use the ame of a
match or candle, or smoke from a cigarette, cigar, or pipe.
f) After it has been determined that each appliance remaining connected to the common venting system properly vents
when tested as outlined above, return doors, windows, exhaust fans, replace dampers and any other gas-burning
appliances to their previous condition 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. 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 10
of the National Fuel Gas Code, ANSI Z223.1.

11
11
VII Steam Piping
NOTICE:
Do not use copper for steam piping for the following reasons:
1. High coefficient of thermal expansion can induce mechanical stresses and cause expansion/
contraction noises if not accounted for in piping system design and installation.
2. High heat transfer rate (heat loss) of uninsulated copper piping must be included in normal piping
and pickup factors used to size the boiler.
3. Soldering or brazing pastes and fluxes that end up in the system can cause poor heat transfer,
surging, an unsteady water line and wet steam if not thoroughly removed during the skimming
procedure.
4. Galvanic corrosion of adjoining metal may occur due to dissimilar metals in certain water chemistry if
dielectric unions are not used.
WARNING
•Do not use softened water in steam boilers. Accelerated boiler corrosion will result. Tie in fresh water supply
to boiler upstream of a water softener.
• Oxygen contamination of boiler water will cause corrosion of iron and steel boiler components, and can
lead to boiler failure. Check for and correct system leaks.
!
General Piping Notes
Figures 7.2 through 7.4 shows recommended near boiler piping for most common types of gravity return steam systems.
Additional information on steam system design may be found in the I=B=R Residential Hydronic Heating Guide (Pub. RHH)
published by Air Conditioning Contractors of America (ACCA).
One of the primary purposes of this near boiler piping is to separate tiny water droplets from the steam exiting the boiler
so that “dry” steam is sent to the system. If the near boiler piping is not correct, wet steam will enter the system and the
following problems may occur:
• Short cycling on low water
• Boiler or system Flooding
• Hammering
• Failure to heat one or more radiators
Avoid the three common piping mistakes shown in Figure 7.5. This applies even if the existing boiler has one of the piping
mistakes shown in Figure 7.5 and appears to be working. If two or more steam mains must be connected to the boiler, connect
a separate take-o for each main into the header between the riser(s) and equalizer. Also note the following points:
1) A size reduction must be made to connect the header to the equalizer. This reduction must be made in the equalizer line.
Do not make this size reduction in the horizontal header.
2) One pipe steam systems require air vents on each radiator, as well as at the end of each main. For the system to work
properly, these vents must be properly installed, sized, and be in good condition. Inspect and replace any defective vents. If
there are no vents at the ends of the mains, install them.
3) The use of gravity returns on a multiple steam boiler installation is not recommended due to potential problems
maintaining a uniform water line in all boilers (even a one ounce per square inch dierence in the pressure of adjacent boilers
will cause a 1 ¾ inch dierence in their water lines).
4) For installations with condensate or boiler feed pumps, follow the pump manufacturer’s selection and installation
instructions. Such systems generally do not require Hartford loops.
5) Do not use a check valve in place of, or in addition to, a Hartford loop on a gravity return system.
6) Pipe the ll connection from a clean source of cold water. When the water supply is from a well, make sure that a strainer
is installed in the well system.

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7) The single most important factor in determining expected life cycle of a steam boiler is the amount of fresh water added
to boiler during operation. Fresh water brings minerals and oxygen into the boiler. These contaminants greatly accelerate
corrosion of cast iron boiler sections. Assure all system radiators, piping and vents are absolutely leak tight.
• If system contains hidden piping (hidden behind walls, buried in concrete, etc.) pressure test this piping and repair
any leaks found.
• Providing a means of monitoring the amount of fresh water added to the system will allow an increase in water
loss to be identied, and the cause corrected, before signicant damage to the boiler occurs. This can be
accomplished using water meter installed in the water feed line. Alternatively, some automatic water feeders, such as
the Hydrolevel VXT Series, have the ability to monitor the total amount of water they have added to the system.
Near-Boiler Piping Installation
1) Install safety valve (spindle must be in vertical position) into tapping on boiler left side using the 3/4” NPT nipples
and elbow supplied (Figure 7.1).
2) Pipe the discharge of the safety relief valve to a location where water or steam will not create a hazard or cause
property damage if the valve opens. The end of the discharge pipe must terminate in an unthreaded pipe.
If the safety valve discharge is not piped to a drain it must terminate at least 6 inches above the oor. The
termination of the safety valve discharge piping must be in an area where it is not likely to become plugged by
debris or subjected to freezing.
WARNING
• Pipe discharge of relief valve to a location where water or steam will not create a hazard or cause property
damage if the relief valve opens.
• End of discharge pipe must terminate in an unthreaded pipe.
• Termination of the relief valve discharge piping must be in an area where it is not likely to become plugged
by debris or subjected to freezing.
!
3) Install drain valve into tapping on boiler left side using the 2 x 3/4 bushing provided (see Figure 7.1).
4) Install the nipple and cap provided in the 1-1/4 skimmer tapping as shown in Figure 7.1.
5) The BSI069 - BSI172 may be piped with either one or two Supply risers as shown in Figures 7.2 and 7.3
respectively. If only one supply riser is used, use the 2” nipple and cap provided to plug the unused supply tapping
(Figure 7.1).
6) The optional “drop header” piping shown in Figure 7.4 is useful when there is limited overhead clearance
between the boiler and the mains. The riser closest to the equalizer can be omitted on the BSI069 through BSI172.
7) The piping shown in Figures 7.2 through 7.4 are shown with the equalizer and return connections on the right
side. This piping can be “ipped” so that the equalizer/return are on the left side and the boiler drain located
on the right. If only one riser is used on the BSI069 through BSI172 it must be located on the side opposite the
equalizer/return.
DANGER
• Do not install any valves between boiler and relief valve.
• Do not install any valves between relief valve and discharge.
• Do not move relief valve from factory specified location.
• Do not plug relief valve discharge.
• Do not install a relief valve with a setting greater than 15 psi.
!

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FIGURE 7.2: STEAM BOILER PIPING FOR GRAVITY RETURN, SINGLE RISER (BSI069 - BSI172 ONLY)
"A" "B" "C" "D"
BSI069 * 2 1 1/2 1 1/4
BSI103 * 2 1 1/2 1 1/4
BSI138 * 2 1 1/2 1 1/4
BSI172 * 2 1 1/2 1 1/4
BOILER
MODEL
MINIMUM PIPE DIA. (IN NPT)
* SECOND 2" SUPPLY RISER OPTIONAL
FIGURE 7.1: INSTALLATION OF FACTORY SUPPLIED FITTINGS

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FIGURE 7.3: STEAM BOILER PIPING FOR GRAVITY RETURN, DUAL RISER
"A" "B" "C" "D"
BSI069 2 2 1 1/2 1 1/4
BSI103 2 2 1 1/2 1 1/4
BSI138 2 2 1 1/2 1 1/4
BSI172 2 2 1 1/2 1 1/4
BSI207 2 3 1 1/2 1 1/4
BSI241 2 3 2 1 1/2
BSI276 2 3 2 1 1/2
BSI311 2 3 2 1 1/2
BSI346 2 3 2 1 1/2
BSI380 2 3 2 1 1/2
BOILER
MODEL
MINIMUM PIPE DIA. (IN NPT)
FIGURE 7.4: STEAM BOILER PIPING FOR GRAVITY RETURN, DROP HEADER PIPING
"A" "B" "C" "D"
BSI069 2* 2 1 1/2 1 1/4
BSI103 2* 2 1 1/2 1 1/4
BSI138 2* 2 1 1/2 1 1/4
BSI172 2* 2 1 1/2 1 1/4
BSI207 2 3 1 1/2 1 1/4
BSI241 2 3 2 1 1/2
BSI276 2 3 2 1 1/2
BSI311 2 3 2 1 1/2
BSI346 2 3 2 1 1/2
BSI380 2 3 2 1 1/2
MINIMUM PIPE DIA. (IN NPT)BOILER
MODEL
* SECOND 2" SUPPLY RISER OPTIONAL

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FIGURE 7.5: COMMON NEAR-BOILER PIPING MISTAKES