SG Series Boilers – Installation and Service Manual
18
2.4 GAS SERVICE PIPING
The boiler and its gas connection must be leak tested before placing the boiler in operation. The gas
controls furnished are suitable for a maximum operating gas pressure of 1/2 psi (14 inches water
column).
The boiler and its individual shutoff valve must be disconnected from the gas supply piping system during
any pressure testing of that system at test pressures in excess
of 1/2 psig (14 inches water column).
The boiler must be isolated from the gas supply piping system by closing its individual manual shutoff
valve during any pressure testing at test pressures equal to or less than
1/2 psig (14 inches water column).
A manual main shut-off valve should be installed in the gas line outside the boiler jacket and as required
in Section 2.2. The valve should be readily accessible for turning on and off.
A drip pocket or sediment trap should be installed in the gas supply line upstream of the gas controls and
as close to the boiler as possible (example shown in Figure 8 in Section 5).
Some of the pressure regulators or pressure regulating sections of gas valves are provided with an
integral vent limiter and threaded connection. A bleed or gas relief line should be connected to it and
piped to the outdoors.
The pipe compound used should be resistant to the action of liquefied petroleum gases. Check for gas
leaks in piping before placing the boiler in operation by using a soap and water solution. DO NOT USE
AN OPEN FLAME.
INSTALLER MUST IDENTIFY EMERGENCY SHUT-OFF DEVICES.
All piping and fittings must be installed as per codes in Section 2.2.
2.5 AIR SUPPLY FOR COMBUSTION AND VENTILATION
A sufficient air supply MUST be provided to this boiler. Air openings to the boiler room provide the air for
combustion, flue gas dilution and ventilation and are always required, regardless whether the air is taken
from inside or outside. The air opening size and location (as well as other air supply and venting
considerations) must conform to Section 2.2.
The boiler room must never be under a negative pressure. Always provide air openings sized not only to
the dimensions required for the total input of all fuel-fired appliances in the boiler space, but also to
handle the air movement rate of any exhaust fans or air movers using air from the building or space.
The venting terminations must always be kept clear of obstructions (i.e. snow, ice, etc.). Louvers and
grilles used in the air supply and ventilation system should be kept clear of any dust, dirt, or debris which
will block proper air flow.
2.6 CORROSIVE ATMOSPHERES
If a gas boiler is to be installed near a corrosive or potentially corrosive air supply, the boiler should be
isolated from it and outside air should be supplied as recommended in Section 2.5.
Chemical vapors from products containing chlorine or fluorine must be avoided. Even though these
chemicals may be safe to breathe, corrosive substances can become liberated when passed through a
gas flame. Even at low concentrations, these chemicals can significantly contaminate the air supply and
shorten the life of any gas burning appliance. The following is a list of some of the products which should
be avoided:
• bleaches and chlorinated cleaning products
• paints and sprays
• water softeners (calcium or sodium chloride)
• leaking refrigeration equipment
• freon from common aerosol dispensers
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