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V. Gas Piping
WARNING
Failure to properly pipe gas supply to boiler
may result in improper operation and dam-
age 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.
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. The
minimum and maximum gas valve inlet pressure is
stamped on the rating label and can be found in table
3.
2. Maximum gas demand. Refer to the boiler's input
found in Figure 1 or as printed on it's rating label.
Also consider existing and expected future gas
utilization equipment (i.e. water heater, cooking
equipment).
3. Length of piping and number of fittings. Refer to
Table 5 for maximum capacity of Schedule 40 pipe.
Table 6 lists equivalent pipe length for standard fit-
tings.
Table 3: Gas Ratings
Maximum
Boiler
Gas Pressure
Model
(in. w.c.)
SOL-300
14
SOL-500
14
SOL-750
14
SOL-1000
14
SOL-1250
14
SOL-1500
14
USA boilers built for installation at altitudes greater than 2,000 feet above sea level have been
specifically orificed to reduce gas input rate 4 percent per 1,000 feet above sea level per the
National Fuel Gas Code, NFPA 54/ANSI Z223.1.
4
Minimum
Manifold
Gas Pressure
Pressure
(in. w.c.)
(in. w.c.)
4.5
3.5
4.5
1.3
4.5
2.3
4.5
1.9
4.5
1.5
4.5
1.3
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 5, 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.
Table 4: Specific Gravity Correction Factors
Specific
Gravity
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
1.00
For materials or conditions other than those listed above, re-
fer to National Fuel Gas Code, NFPA54/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.
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 14.
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, NFPA 70.
C.
Pressure test. The boiler and its gas connection must be
NOTICE
Correction
Specific
Correction
Factor
Gravity
1.10
1.10
1.04
1.20
1.00
1.30
0.96
1.40
0.93
1.50
0.90
1.60
0.87
1.70
0.84
1.80
0.82
1.90
0.78
2.00
Factor
0.74
0.71
0.68
0.66
0.63
0.61
0.59
0.58
0.56
0.55
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