Service Manual

82
SERVICING
8. Turn on electrical power and verify proper unit opera-
tion.
WARNING
HIGH VOLTAGE
D
ISCONNECT
ALL
ELECTRICAL POWER AND SHUT OFF GAS
SUPPLY BEFORE SERVICING OR INSTALLING THIS UNIT.
MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE TO
DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
Gas Manifold Pressure Measurement and Ad-
justment
Natural Gas Adjustments
WARNING
HIGH VOLTAGE
D
ISCONNECT
ALL
ELECTRICAL POWER AND SHUT OFF GAS SUPPLY
BEFORE SERVICING OR INSTALLING.
NOTE: Use adapter kit #0151K00000S to measure gas
pressure on White-Rodgers 36G54 gas valves.
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 follow-
ing procedure.
1. After turning off gas to furnace at the manual gas shut-
off valve external to the furnace, remove burner com-
partment door to gain access to the gas valve.
2. Connect a calibrated water manometer (or appropriate
gas pressure gauge) at the gas valve outlet pressure
tap. Refer to Measuring Gas Pressure: Two-Stage
Valves figure for two-stage gas valve outlet pressure
tap connections.
LINE VOLTAGE NOW PRESENT
WARNING
3. Turn ON the gas and electrical power supply and oper-
ate the furnace.
4. White-Rodgers 36G54 Valves:
a. Back outlet pressure test screw (inlet/outlet pres-
sure boss) out one turn (counterclockwise, not more
than one turn).
b. Attach a hose and manometer to the outlet pressure
outlet pressure boss.
c. Turn ON the gas supply.
d. Turn on power and close thermostat “R” and “W1”
contacts to provide a call for low stage heat.
e. Measure the gas manifold pressure with burners fir-
ing. Adjust manifold pressure using the Manifold Gas
Pressure table shown below.
f. Remove regulator cover screw from the low (LO) out-
let pressure regulator adjust tower and turn screw
clockwise to increase pressure or counterclockwise
to decrease pressure. Replace regulator cover screw.
g. Close thermostat “R” and “W2” contacts to provide a
call for high stage heat.
h. Remove regulator cover screw from the high (HI) out-
let pressure regulator adjust tower and turn screw
clockwise to increase pressure or counterclockwise
to decrease pressure. Replace regulator cover screw.
i. Turn off all electrical power and gas supply to the
system.
j. Remove the manometer hose from the hose barb fit-
ting or outlet pressure boss.
k. Turn outlet pressure test screw in to seal pressure
port (clockwise, 7 in-lb minimum).
5. Honeywell VR8215 Valve:
a. Remove the outlet pressure boss plug. Install an 1/
8" NPT hose barb fitting into the outlet pressure tap.
b. Attach a hose and manometer to the outlet pressure
barb fitting.
c. Turn ON the gas supply.
d. Turn on power and close thermostat “R” and “W1”
contacts to provide a call for low stage heat.
e. Measure the gas manifold pressure with burners fir-
ing. Adjust manifold pressure using the Manifold Gas
Pressure table shown below.
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High Fire Regulator
Adjust
Regulator
Vent
Measuring Manifold Gas Pressure
(36G54 Valve)