GC9C80 Installation Manual
19
High altitude kits are purchased according to the installation
derate the furnace by adjusting the manifold pressure
The combination of the lower air density and a lower manifold
-
er amount of air into the burner. This may cause incomplete
3
content of the
3
for use with L.P. gas. Refer to the section on PROPANE GAS/
-
propriate kits. The indicated kits must be used to insure safe
and proper furnace operation. All conversions must be per-
This unit is equipped with a 24 volt gas valve controlled
during furnace operation by the integrated control module.
regulator spring with a propane gas spring from an appro-
priate manufacturer’s propane gas conversion kit. Taps for
measuring the gas supply pressure and manifold pressure
are provided on the valve.
position. Refer to the lighting instructions label or Startup
Procedure & Adjustment for use of this control during start
up and shut down periods.
The gas piping supplying the furnace must be properly sized
and length of the run. The gas line installation must comply
with local codes, or in their absence, with the latest edition of
Length of Nominal Black Pipe Size
1/2" 3/4" 1" 1 1/4" 1 1/2"
10 132 278 520 1050 1600
20 92 190 350 730 1100
30 73 152 285 590 980
40 63 130 245 500 760
50 56 115 215 440 670
60 50 105 195 400 610
70 46 96 180 370 560
80 43 90 170 350 530
90 40 84 160 320 490
100 38 79 150 305 460
0.60 Specif ic Gravity Gas)
To connect the furnace to the building’s gas piping, the in-
staller must supply a ground joint union, drip leg, manual
In some cases, the installer may also need to supply a tran-
sition piece from ½” pipe to a larger pipe size.
The following stipulations apply when connecting gas pip-
ing. Refer to Gas Piping Connections
line connections to the furnace.
• Gas piping must be supported external to the furnace
cabinet so that the weight of the gas line does not distort
the burner rack, manifold or gas valve.