1080 ft
3
/hr
From the natural gas maximum capacities
table, at 100 ft and 1080 ft
3
/hr the required
minimum pipe size is 2”.
A 100 ft pipe run is needed for a 270 MBH
propane gas heater.
270 MBH = 270 kBtu/hr
From the propane gas maximum capacities
table, at 100 ft and 270 kBtu/hr the required
minimum pipe size is 1”.
Inlet and Manifold Pressures
For natural gas units, the minimum inlet gas
pressure to the unit is 6”wc and maximum
inlet gas pressure to the unit is 10.5”wc. For
propane units, the minimum inlet gas
pressure to the unit is 11”wc and the
maximum inlet gas pressure to the unit is
13”wc.
A field provided 1/8” NPT pressure tap is
required to be installed in the piping just
upstream of the shutoff valve for test gage
connection to allow checking of the gas
supply pressure at the unit.
A factory installed pressure tap on the outlet
end of the gas valve can be used to verify a
manifold pressure of 3.5”wc for natural gas,
or 10.5”wc for propane V3-A & V3-B
(10.0”wc on size V3-C).
Gas Pressure Regulator & Overpressure
Protection Device
A gas pressure regulator must be installed if
natural gas supply pressure to the unit is
greater than 10.5”wc and less than 2 psi
(55.4”wc). Regulators must comply with the
latest edition of the Standard for Line
Pressure Regulators, ANSI Z21.80/CSA
6.22.
Both a gas pressure regulator and
overpressure protection device (OPD) must
be installed if gas supply pressure to the unit
is greater than 2 psi (55.4”wc) and less than
5 psi (138.4”wc), in compliance with ANSI
Z21.80/CSA 6.22. For proper heater
operation, pressure to the regulator MUST
NOT be greater than 5 psi (138.4”wc).
Piping Supports
Gas supply piping must be supported directly
at the connection to the unit and at intervals
listed in the following table with metal straps,
blocks, or hooks. Piping should not be
strained or bent.
Table 14 - Gas Piping Supports
To Next Page
Loading...
