GMES8 GCES8 Service Manual

SERVICING
51
4. Measure gas manifold pressure with burners ring. Adjust
manifold pressure using the table below.
3.5" w.c.
10.0" w.c.
Manifold Gas Pressure
Natural Gas
Propane Gas
The nal manifold pressure must not vary more than ± 0.3
“ w.c. from the above specied pressures. Any necessary
major changes in gas ow rate should be made by changing
the size of the burner orice.
5. White-Rodgers 36G22 Valves:
a. Back outlet pressure test screw (inlet/outlet pressure
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 r-
ing. Adjust manifold pressure using the Manifold Gas
Pressure table shown below.
f. Remove regulator cover screw from the outlet pres-
sure 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 tting
or outlet pressure boss.
k. Turn outlet pressure test screw in to seal pressure port
(clockwise, 7 in-lb minimum).
6. Honeywell VR8215 Valve
a. Remove the outlet pressure boss plug. Install an 1/8"
NPT hose barb tting into the outlet pressure tap.
b. Attach a hose and manometer to the outlet pressure
barb tting.
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 r-
ing. Adjust manifold pressure using the Manifold Gas
Pressure table shown below.
f. Remove regulator cover screw from the outlet pres-
sure 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 tting
or outlet pressure boss.
k. Remove the 1/8" NPT hose barb tting from the outlet
pressure tap. Replace the outlet pressure boss plug
and seal with a high quality thread sealer.
WARNING
HIGH VOLTAGE
D
ISCONNECT
ALL
ELECTRICAL POWER AND SHUT OFF GAS
SUPPLY BEFORE SERVICING OR INSTALLING THIS UNIT.
M
ULTIPLE POWER SOURCES MAY BE PRESENT.
F
AILURE TO
DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.
7. Turn on gas to furnace and check for leaks. If leaks are
found, repair and then reinstall burner compartment door.
8. Turn on electrical power and verify proper unit operation.
Pressure Regulator
Adjustment
(Under Cap Screw)
Gas Valve
On/Off
Selector
Switch
INLET
OUTLET
Inlet Pressure
Tap
Outlet Pressure
Tap
White-Rodgers Model 36J22 (Single-Stage)
Gas Valve On/Off
Selector Switch
Inlet
Pressure
Tap
Pressure Regulator
(under cap screw)
Outlet
Pressure
Tap
Honeywell Model VR8215
WARNING
HIGH VOLTAGE
D
ISCONNECT ALL
ELECTRICAL POWER AND SHUT OFF GAS SUPPLY
BEFORE SERVICING OR INSTALLING.
Gas Rate Range Nominal
High Stage 9.7 to 10.3" w.c. 10.0" w.c.
Manifold Gas Pressure
Propane Gas