# 45465K005
Page 22
4.
The remaining speed taps must be connected to
dummy terminals marked “PARK” on the control board.
Checking and Adjusting Gas Input
The minimum permissible gas supply pressure for the pur-
pose of input adjustment is 5" W.C. for natural gas or
11" W.C. for propane gas. This furnace requires conversion for
use with propane (see
Accessories
section on page 27 for
correct kit). The maximum inlet gas supply pressure is 10.5"
W.C. for natural gas and 13" W.C. for propane. Gas input must
never exceed the value shown on the furnace rating plate.
G1D80BR and G1D80BT Models
G1D80BR and G1D80BT units are equipped for rated
input at manifold pressures of 3.5" W.C. for natural gas or
10.0" W.C. for propane gas.
To measure inlet or outlet pressure on the G1D80BR and
G1D80BT models, remove plug from desired pressure tap
(inlet or outlet) as shown in Figure 26 and connect a water
manometer or gauge to the proper pressure tap.
The furnace rate must be /- 2% of
the appliance rating input.
CAUTION
To adjust the regulator, disconnect the hose and remove
the barbed fitting in the downstream side of the gas valve.
Turn the adjusting screw on the regulator clockwise to
increase pressure and input; counterclockwise to de-
crease pressure and input.
Replace the barbed fitting and reconnect the hose after
adjusting the regulator. Be sure to replace the inlet and outlet
pressure tap plugs after testing and/or adjusting gas input.
To continue the checking and adjusting gas input procedure
on G1D80BR and G1D80BT models, see
For Natural Gas:
on next page.
G2D80CR and G2D80CT Models
G2D80CR and G2D80CT units are equipped for rated
input at manifold pressures of 1.7" W.C. (1
st
stage) and
3.5" W.C. (2
nd
stage) for natural gas. When these model
furnaces have been converted for use with propane gas,
the manifold pressures are 4.9" W.C. (1
st
stage) and
10.0" W.C. (2
nd
stage).
To measure inlet or outlet pressure on the G2D80CR and
G2D80CT models, remove plug from desired pressure tap
(inlet or outlet) as shown in Figure 27 and connect a water
manometer or gauge to the proper pressure tap.
G2D80CR and G2D80CT models have separate adjusting
screws (3/32" hex) for 1
st
stage (marked “LO”) and 2
nd
stage
(marked “HI”). The adjusting screws are positioned on
either side of the barbed fitting (see Figure 27). Turn the
adjusting screws clockwise to increase pressure and input;
counterclockwise to decrease pressure and input. The
pressure regulator adjustment is sensitive; one turn of the
adjusting screw will result in a relatively large change in
manifold pressure.
To adjust the regulator on G2D80CR and G2D80CT models:
1.
Set high-fire (2
nd
stage) setting by turning hex adjust-
ment screw to desired rate.
2.
Set low-fire (1
st
stage) setting by turning hex adjust-
ment screw to desired rate.
Checking and Adjusting Gas Input
(G2D80CR/G2D80CT Models)
Figure 27
OFF
ON
Inlet Pressure Tap
1/8" NPT
Outlet Pressure Tap
1/8" NPT
High-Fire (2 Stage) Adjustment
Under Vent Cap
nd
Low-Fire (1 Stage) Adjustment
Under Vent Cap
st
Checking and Adjusting Gas Input
(G1D80BR/G1D80BT Models)
Figure 26
Regulator Adjustment
Under Barbed Fitting
Inlet
Pressure Tap
1/8 NPT
"
Outlet
Pressure Tap
1/8 NPT
"
