GM9C96 Service Manual
SERVICING
29
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High Fire Regulator
Adjust
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Common
Terminal(C)
White-Rodgers Model 36J54 Connected to Manometer
3.5
1. Turn OFF gas to furnace at the manual gas shuto
valve external to the furnace.
2. Connect a calibrated manometer (or appropriate gas
pressure gauge) at either the gas valve inlet pressure
tap or the gas piping drip leg. See White-Rodgers
36J54 gas valve gure for location of inlet pressure tap.
Natural Gas Minimum: 4.5" w.c. Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
If measuring gas pressure at the drip leg, a
eld-supplied hose barb tting must be installed prior
to making the hose connection. If using the inlet pres-
sure tap on the White-Rodgers 36J54 gas valve, then
use the 36G/J Valve Pressure Check Kit, Part No.
0151K00000S.
3. Turn ON the gas supply and operate the furnace and
all other gas consuming appliances on the same gas
supply line.
4. Measure furnace gas supply pressure with burners
ring. Supply pressure must be within the range speci-
ed in the Inlet Gas Supply Pressure table.
If supply pressure diers from table, make the necessary
adjustments to pressure regulator, gas piping size, etc., and/
or consult with local gas utility.
5. Turn OFF gas to furnace at the manual shuto valve
and disconnect manometer. Reinstall plug before turn-
ing on gas to furnace.
6. Turn OFF any unnecessary gas appliances stated in
step 3.
-
Only small variations in gas pressure should be made by adjusting
the gas valve pressure regulator. The manifold pressure must be
measured with the burners operating. To measure and adjust the
manifold pressure, use the following procedure.
.
T
O
PREVENT
UNRELIABLE
OPERATION
OR
EQUIPMENT
DAMAGE
,
THE
GAS
MANIFOLD
PRESSURE
MUST
BE
AS
SPECIFIED
ON
THE
UNIT
RATING
PLATE
. O
NLY
MINOR
ADJUSTMENTS
SHOULD
BE
MADE
BY
ADJUSTING
THE
GAS
VALVE
PRESSURE
REGULATOR
.
1. Turn OFF gas to furnace at the manual gas shuto
valve external to the furnace.
2. Turn o all electrical power to the system.
3. Outlet pressure tap connections:
White-Rodgers 36J54 valve: Back outlet pressure test
screw (inlet/outlet pressure tap) out one turn (counter-
clockwise, not more than one turn).
4. Attach a hose and manometer to the outlet pressure
tap (White-Rodgers valve).
5. Turn ON the gas supply.
6. Turn on power and close thermostat “R” and “W1” con-
tacts to provide a call for low stage heat.
7. Measure the gas manifold pressure with burners ring.
Adjust manifold pressure using the Manifold Gas Pres-
sure table shown below.
8. Remove regulator cover screw from the low (LO) outlet
pressure regulator adjust tower and turn screw clock-
wise to increase pressure or counterclockwise to de-
crease pressure. Replace regulator cover screw.
9. Close thermostat “R”, “W1” and “W2” contacts to pro-
vide a call for high stage heat.
10. Remove regulator cover screw from the high (HI) outlet
pressure regulator adjust tower and turn screw clock-
wise to increase pressure or counterclockwise to de-
crease pressure. Replace regulator cover screw.
11. Turn o all electrical power and gas supply to the sys-
tem.