64
SERVICING
WARNING
D
ISCONNECT ELECTRICAL POWER AND SHUT OFF GAS SUPPLY.
1. After turning off gas to furnace at the manual gas shutoff
valve external to the furnace, remove burner compartment
door to gain access to the gas valve.
2. Connect a calibrated water manometer (or appropriate
gas pressure gauge) at either the gas valve inlet pressure
tap or the gas piping drip leg as shown in the following
figures.
NOTE:
At either location, a hose fitting must be installed prior
to making the hose connection.
.
Measuring Inlet Gas Pressure
(Alternate Method)
3. Turn ON the gas and electrical power 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 firing.
Supply pressure must be within the range specified in the
following table.
Natural Gas
Minimum: 4.5" w.c.
Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
INLET GAS SUPPLY PRESSURE
If supply pressure differs from above, make necessary ad
-
justments to pressure regulator, gas piping size, etc., and/or
consult with local gas utility.
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.
5. Disconnect manometer after turning off gas at manual
shutoff valve. Reinstall plug before turning on gas to fur
-
nace.
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 compartment door.
8. Turn on electrical power and verify proper unit operation.
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.
Gas Manifold Pressure Measurement and Adjustment
Natural Gas Adjustments
WARNING
HIGH
VOLTAGE
D
ISCONNECT
ALL
ELECTRICAL POWER AND SHUT OFF GAS SUPPLY
BEFORE SERVICING OR INSTALLING.
NOTE:
Follow this procedure to test the gas valve pressure
at 100% firing rate.
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.
1. After turning off gas to furnace at the manual gas shutoff
valve external to the furnace, remove burner compartment
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.
L
INE VOLTAGE NOW PRESENT
WARNING
3. Turn ON the gas and electrical power supply and operate
the furnace.
4. White-Rodgers 36J27 Valves:
a. Remove 1/8” N.P.T. plug using 5/16” Allen wrench &
connect proper adapter for manometer connection.
b. Attach a hose and manometer to the outlet pressure
tap.
c. Turn ON the gas supply.