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VIII. Gas Piping
WARNING
Explosion Hazard. Failure to properly pipe gas supply to boiler may result in improper
operation or leaks of flammable gas.
•
Gas supply to boiler and system must be absolutely shut off prior to installing or servicing boiler gas
piping.
•
Always assure gas piping is absolutely leak free and of the proper size and type for the connected load.
•
Use a thread compound compatible with liquefied petroleum gas. Failure to use proper thread
compounds on all gas connectors may result in leaks of flammable gas.
•
If inlet pressure is above 1/2 psig (3.4 kPa) an additional gas pressure regulator is required. Consult gas
supplier.
•
Size corrugated stainless steel tubing (CSST) to ensure proper capacity and minimize flow restrictions.
Gas piping to the boiler must be sized to deliver adequate gas for the boiler to fire at the nameplate
input at an inlet pressure between the minimum and maximum values shown in Table 8.2. When sizing,
also consider other existing and expected future gas utilization equipment (i.e. water heater, cooking
equipment). For more information on gas line sizing, consult the utility or the National Fuel Gas Code,
NFPA54/ANSI Z223.1, and/or CAN/CSA B149.1 Natural Gas and Propane Installation Code.
Figure 8.1 shows typical gas piping connection to the boiler. A sediment trap must be installed upstream
of all gas controls. Install the factory provided manual shut-off valve outside the jacket with a ground joint
union as shown. All above ground gas piping upstream from manual shut-off valve must be electrically
continuous and bonded to a grounding electrode. Refer to National Electrical Code, NFPA 70.
The boiler and its gas connection must be leak tested before placing the boiler in operation. When doing
this, the boiler and its individual shut-off must be disconnected from the rest of the system during any
pressure testing of that system at pressures in excess of 1/2 psi (3.5kPa). When pressure testing the gas
system at pressures of 1/2 psi (3.5kPa) or less, isolate the boiler from the gas supply system by closing its
individual manual shut-off valve. Locate leaks using an appropriate combustible gas non-corrosive leak
detector solution.
DANGER
Explosion Hazard. o not use matches, candles, open flames or other ignition source to
check for leaks.
WARNING
If gas pressure in the building is above ½ psig (3.4 kPa), an additional gas pressure
regulator is required. Using one additional regulator for multiple gas appliances may result in unsafe
boiler operation. The additional regulator must be able to properly regulate gas pressure at the input of
the smallest appliance. If the regulator can not do this, two or more additional regulators are required.
Consult regulator manufacturer and/or local gas supplier for instructions and equipment ratings.
107672-03 - 5/18
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