Burnham 20_PV_I - Manual (Page 8)

8
IV. Gas Piping
A. Size gas piping. Design system to provide adequate
gas supply to boiler. Consider these factors:
1. Allowable pressure drop from point of delivery to
boiler. Maximum allowable system pressure is ½
psig. Actual point of delivery pressure may be less;
contact gas supplier for additional information.
Minimum gas valve inlet pressure is listed on
rating label.
2. Maximum gas demand. Table 1 lists boiler input
rate. Also consider existing and expected future gas
utilization equipment (i.e. water heater, cooking
equipment).
Boiler
Model
Number
Input Rate
[cubic feet per hour]
Gas
Connection
Size
Natural Gas LP/Propane
203PV 62 24 ‰
204PV 96 38‰ ‰
205PV 130 52 ‰
206PV 164 65 ‰
Table 1: Rated Input
3. Length of piping and number of fittings. Refer to
Table 2 for maximum capacity of Schedule 40 pipe.
Table 3 lists equivalent pipe length for standard
fittings.
4. Specific gravity of gas. Gas piping systems for gas
with a specific gravity of 0.70 or less can be sized
directly from Table 2, unless authority having
jurisdiction specifies a gravity factor be applied. For
specific gravity greater than 0.70, apply gravity
factor from Table 4. If exact specific gravity is not
shown choose next higher value.
For materials or conditions other than those listed
above, refer to National Fuel Gas Code, NFPA 54/
ANSI Z223.1, or size system using standard
engineering methods acceptable to authority having
jurisdiction.
B. Connect boiler gas valve to gas supply system.
1. Use methods and materials in accordance with local
plumbing codes and requirements of gas supplier.
In absence of such requirements, follow National
Fuel Gas Code, NFPA 54/ANSI Z223.1 and/or
CAN/CGA B149 Installation Codes.
2. Use thread (joint) compounds (pipe dope) resistant
to action of liquefied petroleum gas.
3. Install sediment trap, ground-joint union and
manual shut-off valve upstream of boiler gas
control valve and outside jacket. See Figure 6.
4. All above ground gas piping upstream from manual
shut-off valve must be electrically continuous and
bonded to a grounding electrode. Do not use gas
piping as grounding electrode. Refer to National
Electrical Code, ANSI/NFPA 70 and/or CSA C22
Electrical Code.
C. Pressure test. The boiler and its gas connection must
be leak tested before placing boiler in operation.
1. Protect boiler gas control valve. For all testing over
½ psig, boiler and its individual shutoff valve must
be disconnected from gas supply piping. For testing
at ½ psig or less, isolate boiler from gas supply
piping by closing boiler's individual manual shutoff
valve.
2. Locate leaks using approved combustible gas
detector, soap and water, or similar nonflammable
solution. Do not use matches, candles, open flames,
or other ignition source.
Figure 6: Recommended Gas Piping