U.S. Boiler Company INDEPENDENCE, Installation, Operating And Service Instructions

Page: 19 / 72

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VI. Gas Piping
WARNING
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.
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 indicated on
Rating Label, located on the vestibule panel.
2. 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. Length of piping and number of fittings. Refer to
Table 4 for maximum capacity of Schedule 40 pipe.
Table 5 lists equivalent length for standard fittings.
4. Corrections for the specific gravity of natural gas
can be found in Table 6.
Table 3: Rated Input
For materials or conditions other than those listed
above, refer to the National Fuel Gas Code , ANSI
Z223.1/NFPA 54 and/or Natural Gas and Propane
Installation Code , CAN/CSA B149.1, or size system
using standard engineering methods acceptable to
authority having jurisdiction.
WARNING
Failure to use proper thread compounds on all
gas connectors may result in leaks of flammable
gas.
WARNING
Gas supply to boiler and system must be
absolutely shut off prior to installing or servicing
boiler gas piping.
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 the National
Fuel Gas Code , ANSI Z223.1/NFPA 54 and/or
Natural Gas and Propane Installation Code , CAN/
CSA B149.1.
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 valve and
outside jacket. See Figure 26.
Figure 26: Recommended Gas Piping
Boiler
Model
Number
Rated Capacity
[cubic feet per hour]
Gas
Connection
Size
Natural LP/Propane
IN3I 62 24¾ ½
IN4I 105 42 ½
IN5I 140 56 ½
IN6I 175 70 ½
IN7I 210 84 ¾
IN8I 245 98 ¾
IN9I 280 112 ¾
IN10 315
(1)
--- ¾
(2)
IN11 349
(1)
--- ¾
( 2)
IN12 385 --- 1
(1)
Reduce IN10 - IN11 input by 3% in Canada
(2)
Gas connection size is 1" on IN10 and IN11
Continuous Ignition (Standing Pilot)