Service Manual
SERVICING
83
Gas Valve On/Off
Selector Switch
Regulator
Vent
High Fire
Regulator
Adjust
Low Fire
Regulator
Adjust
Honeywell Model VR9205 (Two-Stage)
Measuring Gas Pressure: Two-Stage Valves
Cont'd
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Common
Terminal(C)
High Fire Coil
Terminal (HI)
Low Fire Coil
Terminal (LO)
Inlet Pressure Tap
1/8 NPT
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Outlet Pressure Tap
1/8 NPT
Honeywell Model VR9205 Connected to Manometer
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 + W1 + 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 sys-
tem.
j. Remove the manometer hose from the hose barb fit-
ting or outlet pressure boss.
k. Remove the 1/8" NPT hose barb fitting 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.
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.
Make sure furnace operates at the proper manifold pres-
sure at both high and low stage outputs.
Gas Rate Range Nominal
High Stage 3.2 to 3.8" w.c. 3.5" w.c.
Low Stage 1.6 to 2.2" w.c. 1.9" w.c.
Manifold Gas Pressure
Natural Gas
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.
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.
Low Stage 5.7 to 6.3" w.c. 6.0" w.c.
Manifold Gas Pressure
Propane Gas
S-308 CHECKING HOT SURFACE IGNITOR
120V Silicon Nitride Igniter - furnaces use a 120V silicon
nitride igniter for ignition. The normal operating temperature
is approximately 2156°F - 2678°F.
DISCONNECT ALL POWER BEFORE SERVICING.
WARNING
1. Remove burner compartment door to gain access to the
ignitor.