SERVICING
39
CHECKING GAS PRESSURE
Gas Supply Pressure Measurement
CAUTION
To prevent unreliable operation or equipment damage, the
inlet gas supply pressure must be as specified on the unit
rating plate with all other household gas fired appliances
operating.
Gas inlet and manifold pressures should be checked and
adjusted in accordance to the type of fuel being consumed.
The line pressure supplied to the gas valve must be within
the range specified below. The supply pressure can be mea
-
sured at the gas valve inlet pressure tap or at a hose fitting
installed in the gas piping drip leg. The supply pressure must
be measured with the burners operating. To measure the
gas supply pressure, use the following procedure.
WARNING
Disconnect electrical power and shut off gas supply.
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 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 pri
-
or to making the hose connection.
NOTE:
Use adapter kit #0151K00000S to measure gas
pressure on White-Rodgers 36G22 gas valves.
.
Measuring Inlet Gas Pressure
(Alternate Method)
3. Turn ON the gas and electrical power supply and op-
erate the furnace and all other gas consuming appli-
ances on the same gas supply line.
4. Measure furnace gas supply pressure with burners
firing. Supply pressure must be within the range spec
-
ified 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
Disconnect ALL power before servicing or
changing any electrical wiring. Multiple pow
-
er sources may be present. Failure 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
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
operation.
Gas Manifold Pressure Measurement
and Adjustment
CAUTION
To prevent unreliable operation or equipment damage, the
gas manifold pressure must be as specified on the unit rating
plate. Only minor adjustments should be made by adjusting
the gas valve pressure regulator.
NOTE:
Use adapter kit #0151K00000S to measure gas
pressure on White-Rodgers 36J22 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 following
procedure.
