Goodman GMH8 - GAS PRESSURE MEASUREMENT AND ADJUSTMENT

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Gas Line
Gas
Shutoff
Valve
Gas Line
To Furnace
Drip Leg Cap
With Fitting
Manometer Hose
Manometer
Open To
Atmosphere
Measuring Inlet Gas Pressure (Alt. Method)
NOTE: If measuring gas pressure at the drip leg, a field supplied
hose barb fitting must be installed prior to making the hose
connection. If using the inlet pressure boss on the gas valve,
then use the 36G Valve Pressure Check Kit, Goodman Part No.
0151K00000S.
3. Turn ON the gas 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
Inlet Gas Supply Pressure table.
Natural Gas
Minimum: 5.0" 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 table, make the necessary
adjustments to pressure regulator, gas piping size, etc., and/or
consult with local gas utility.
5. Turn OFF gas to furnace at the manual shutoff valve and
disconnect manometer. Reinstall plug before turning on
gas to furnace.
6. Turn OFF any unnecessary gas appliances started in step
3.
GAS MANIFOLD PRESSURE MEASUREMENT AND ADJUSTMENT
CAUTION
T
O PREVENT UNRELIABLE OPERATION OR EQUIPMENT DAMAGE, THE GAS
MANIFOLD PRESSURE MUST BE AS SPECIFIED ON THE UNIT RATING PLATE.
O
NLY MINOR ADJUSTMENTS SHOULD BE MADE BY ADJUSTING THE GAS VALVE
PRESSURE REGULATOR.
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.
3. White-Rodgers Model 36G54: Push switch to the OFF
position.
4. Close manual gas shutoff valve external to the furnace.
5. Replace the door on the unit.
GAS SUPPLY PRESSURE MEASUREMENT
CAUTION
T
O 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.
WHITE-RODGERS 36G54 GAS VALVE
The line pressure supplied to the gas valve must be within the
range specified. The supply pressure can be measured at the
gas valve inlet pressure boss 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.
On/Off Switch
Inlet
Pressure Boss
High Fire
Coil Terminal (HI)
Low Fire
Regulator Adjust
M
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M
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A
High Fire Regulator
Adjust
Regulator
Vent
Common
Terminal (C)
Coaxial Coil
Terminal (M)
Outlet
Pressure Boss
Open to
Atmosphere
White-Rodgers Model 36G54 Connected to Manometer
1. Turn OFF gas to furnace at the manual gas shutoff valve
external to the furnace.
2. Connect a calibrated water manometer (or appropriate gas
pressure gauge) at either the gas valve inlet pressure boss
or the gas piping drip leg.