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V. Gas Piping
Failure to properly
pipe gas supply to boiler may
result in improper operation and damage to the
boiler or structure.
Always assure gas piping is
absolutely
leak free and of the proper size and
type for the connected load.
An additional
gas pressure
regulator
may be
needed. Consult gas supplier.
B.
Connect
boiler gas valve to gas supply system.
Ao
Size gas piping.
Design system to provide
adequate
gas
supply to boiler. Consider
these factors:
1.
2.
Table
Allowable pressure drop from point of delivery to
boiler. Maximum allowable system pressure is */2
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 on front of boiler.
Maximum gas demand. Table 3 lists boiler input
rate. Also consider existing and expected future gas
utilization equipment (i.e. water heater, cooking
equipment).
3: Rated Input
Boiler
Model
Number
Input Rate
[cubic feet per hour]
Gas
Connection
Size
Natural
Gas
62
96
130
164
LP/Propane
243A
38½
52
653A
PVCG30
½
PVCG40
½
PVCG50
½
PVCG60
½
3. Length of piping and number of fittings. Refer to
Table 4 for lnaxilnuln capacity of Schedule 40 pipe.
Table 5 lists equivalent pipe length for standard
fittings.
4. Specific gravity of gas. Corrections for the specific
gravity of natural gas can be found in Table 6.
For materials or conditions other than those listed
above, refer to National Fuel Gas ('ode, NFPA
54/ANSI Z223.1, or size system using standard
engineering methods acceptable to authority having
jurisdiction.
_
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 ('ode, NFPA 54/ANSI Z223.1.
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.
See Figure 10.
4.
I',11 N ,_ ..i . ...............................
[:
°
C¢,pj,
'/'
Figure 10: Recommended
Gas Piping
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 ('ode, ANSI/NFPA 70.
18
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