Install Instructions

31
Gas Piping
NATURAL GAS
Pipe Sizing - Natural Gas
Refer to Table 1 for schedule 40 metallic pipe
length and diameter requirements for natural
gas, based on rated CHALLENGER input
(divide by 1,000 to obtain cubic feet per hour).
- Table 1 is based on Natural Gas with a spe-
cific gravity of 0.60 and a pressure drop
through the gas piping of 0.30”w.c. [0.75
mbar].
- For additional gas piping sizing informa-
tion, refer to ANSI Z223.1. For Canadian
installations refer to B149.1.
Natural Gas Supply Pressure Requirements
1. Pressure required at the gas valve inlet
supply pressure port:
- Maximum 13”w.c. [32 mbar] at flow or
no flow conditions to the burner.
- Minimum 5”w.c. [13 mbar] during flow
conditions to the burner. Must be veri-
fied during start up and with all other
gas appliances operating within the gas
piping service.
- Maximum gas inlet pressure must not
be exceeded and minimum gas inlet
pressure is for the purpose of input
adjustment.
2. Install 100% lockup gas pressure regulator
in the gas supply line if inlet pressure can
exceed 13”w.c. [32 mbar] at any time.
Adjust the lockup pressure regulator for
13”w.c. [32 mbar] maximum.
DO NOT adjust or attempt to measure
gas valve outlet pressure. The gas valve
is factory-set for the correct outlet pres-
sure. This setting is suitable for natural
and propane gas and requires no field
adjustment. Attempts by the installer to
adjust or measure the gas valve outlet
pressure could result in damage to the
valve, causing potential severe personal
injury, death or substantial property
damage.
Table 2: Natural Gas Orifice Requirements
WARNING
Length of Pipe in
Feet
Capacity of Schedule 40 Metallic Pipe in Cubic Feet of Natural Gas Per
Hour (based on 0.60 specific gravity, 0.30" w.c. pressure drop)
SCH 40 1/2" 3/4" 1" 1-1/4" 1-1/2"
10 132 278 520 1050 1600
20 92 190 350 730 1100
30 73 152 285 590 890
40 63 130 245 500 760
50 56 115 215 440 670
75 45 93 175 360 545
100 38 79 150 305 460
150 31 64 120 250 380
Table 1: Gas Piping Sizing - Natural Gas
CHALLENGER
MODEL
Natural
Orifice Size
Orifice
Marking
CC85 0.256” [6.50 mm] 650
CC105 0.256” [6.50 mm] 650
CC125 0.285” [7.25 mm] 725