Goodman AMH8 Service Instructions Manual page 57

SERVICING
HIGH VOLTAGE
D ALL
ISCONNECT ELECTRICAL POWER AND SHUT OFF GAS
SUPPLY BEFORE SERVICING OR INSTALLING THIS UNIT.
M
ULTIPLE POWER SOURCES MAY BE PRESENT.
DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
5. Disconnect manometer after turning off gas at manual
shutoff valve. Reinstall plug before turning on gas to
furnace.
6. Turn OFF any unnecessary gas appliances started in
step 3.
7. Turn on gas to furnace and check for leaks. If leaks
are found, repair and then reinstall burner compart-
ment door.
8. Turn on electrical power and verify proper unit opera-
tion.
HIGH VOLTAGE
D ALL
ISCONNECT ELECTRICAL POWER AND SHUT OFF GAS
SUPPLY BEFORE SERVICING OR INSTALLING THIS UNIT.
M
ULTIPLE POWER SOURCES MAY BE PRESENT.
DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
Gas Manifold Pressure Measurement and Adjust-
ment
Natural Gas Adjustments
To test & set low fire manifold gas pressure on the H model
furnace it is recommended that dip switch #2 be set to the
"Two Stage" position and dip switch #3 be set to 5 minute
delay. Operating sequence will be; high fire ignition, after
several seconds the burner input will go to low fire for a 5
minute period. Low fire can be set during this time. To
check & set high fire it is recommended that dip switch #2
be set to single stage for the test period.
HIGH VOLTAGE
D ALL
ISCONNECT 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 fol-
lowing 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 appropri-
WARNING
F
AILURE TO
WARNING
F
AILURE TO
WARNING
ate gas pressure gauge) at the gas valve outlet pres-
sure tap. Refer to Measuring Gas Pressure: Two-
Stage Valves figure for two-stage gas valve outlet pres-
sure tap connections.
WARNING
L
INE VOLTAGE NOW PRESENT
3. White-Rodgers 36G54 Valves:
a. Back outlet pressure test screw ( out one turn (coun-
terclockwise, not more than one turn).
b. Attach a hose and manometer to the outlet pressure.
c. Turn ON the gas supply. Set dip switch #2 set to "two
stage"& dip switch #3 set to "5 minutes"
d. Turn on power and close thermostat "R" and "W"
contacts to provide a call for heat. The burners will
light in high fire and go to low fire after several sec-
onds.
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) outlet
pressure regulator adjust tower and turn screw clock-
wise to increase pressure or counterclockwise to de-
crease pressure. Replace regulator cover screw.
Open thermostat circuit to end the call for heat. Once
the indoor blower turns off, turn off power to fur-
nace.
g. To check & set high fire, set switch#2 to single stage.
Turn on furnace power, close thermostat "R" and
"W" contacts to provide a call for heat.
h. Remove regulator cover screw from the high (HI)
outlet 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
fitting or outlet pressure boss.
k. Turn outlet pressure test screw in to seal pressure
port (clockwise, 7 in-lb minimum).
57