Gas Piping - PEERLESS Stainless Steel Gas Boilers Installation, Operation & Maintenance Manual

GAS PIPING

4. GAS PIPING
1. Size and install the gas supply piping properly in
order to provide a supply of gas sufficient to meet
the maximum demand without exceeding a pressure
drop greater than .5" W.C. between the meter and
the boiler.
2. Determine the volume of gas to be provided to the
boiler in cubic feet per hour. To obtain this value,
divide the Btu per hour rating (on the boiler rating
label) by the heating value of the gas in Btu per
cubic feet. Obtain the heating value of the gas from
the gas supplier. As an alternative, use Table 4.1 or
4.2 on the next page to obtain the volume of gas to
be provided to the boiler.
3. Use the value obtained above as the basis for piping
sizing. Size the gas piping in accordance with Table 3
for natural gas. Consult the National Fuel Gas Code
ANSI Z223.5/NFPA 54 and/or CAN/CGA B149 for
other sizing options and LP gas pipe sizes.
4. Locate the drop pipe adjacent to, but not in front of
the boiler.
5. Install a sediment trap. See Figure 4.1. Locate a tee
in the drop pipe at same elevation as the gas inlet
connection to the boiler. Extend the drop pipe to a
pipe cap.
6. Install a ground joint union ahead of the gas control
assembly to permit servicing of the control. Install a
service valve as shown in Figure 4.1.
WARNING
Use a pipe joint sealing compound that is resistant to
the action of liquefied petroleum gas. A non-resistant
compound may lose sealing ability in the presence of
this gas, resulting in a gas leak and fire or explosion
potential.
7. Check piping for leaks prior to placing the boiler in
operation.
Use an approved gas detector, a non-corrosive leak
detection fluid or other leak detection method. If
leaks are found, turn off all gas flow and repair as
necessary.
WARNING
When checking for leaks, do not use matches,
candles, open flames or other methods that provide a
source of ignition. This can ignite a gas leak,
resulting in fire or explosion.
8. The gas piping connection to the boiler must be a
minimum of 3/4 pipe size. Boiler is provided with a
3/4 x 1/2 pipe reducer. Do not remove the reducer.
12
Figure 4.1:Gas Connection to Boiler
9. Disconnect the boiler and its individual shut-off valve
from the gas supply piping system during any
pressure testing of that system at test pressure in
excess of 1/2 psig (3.5 kPa). Remove the mounting
screws of the flanged gas connection on the gas
valve, and disconnect flange from valve.
CAUTION
Do not subject the gas valve to more than 1/2 psi
pressure. Doing so may damage the valve.
Isolate the boiler from the gas supply piping system
by closing its individual service valve during any
pressure testing of the gas supply piping system at
test pressure equal to or less than 1/2 psig (3.5 kPa).
10. Check for proper supply pressures to boiler at
sediment trap location. Remove pipe cap and
provide fittings as required. Minimum permissible
supply pressure (Inches Water Column):
Natural Gas
LP Gas
Maximum permissible supply pressure to the boiler
(Inches Water Column):
Natural Gas
LP Gas
11. Maintain a minimum distance of 10 feet between a
gas pressure regulator and boiler.
12. Gas line must be properly purged of air to allow for
normal main burner ignition.
3.7"
3.7"
13.5"
13.5"