Checking Gas Pressure - Goodman GM9S80 Service And Troubleshooting

SERVICING
The length of Dimension "A" determines the angle of Gas
Stream "B".
A dent or burr will cause a severe deflection of the gas
stream.

CHECKING GAS PRESSURE

Gas Supply Pressure Measurement
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 appliance 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.
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 follow-
ing figures. Refer to Measuring Gas Pressure: Single
Stage Valves figure for single stage valve inlet pres-
sure tap connections.
NOTE: At either location, a hose fitting must be installed
prior to making the hose connection.
36
A
GAS
STREAM B
DENT OR
BURR
GAS
STREAM B
CAUTION
WARNING
NOTE: Use adapter kit #0151K00000S to measure gas
pressure on White-Rodgers 36J22 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.
INLET GAS SUPPLY PRESSURE
Natural Gas Minimum: 4.5" w.c.
Propane Gas Minimum: 11.0" w.c.
If supply pressure differs from above, make necessary ad-
justments to pressure regulator, gas piping size, etc., and/or
consult with local gas utility.
HIGH VOLTAGE
Disconnect 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.
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.
.
Maximum: 10.0" w.c.
Maximum: 13.0" w.c.
WARNING