Goodman GMV series - Gas Manifold Pressure Measurement and Adjustment (80% & 90% Single-Stage Furnaces)

120
SERVICING
GAS LINE
GAS SHUTOFF VALVE
GAS LINE
TO FURNACE
DRIP LEG CAP
WITH FITTING
MANOMETER HOSE
MANOMETER
OPEN TO
ATMOSPHERE
Measuring Inlet Gas Pressure
(Alternate Method)
3. Turn ON the gas and electrical power supply and oper-
ate the furnace and all other gas consuming appliances
on the same gas supply line.
4. Measure furnace gas supply pressure with burners fir-
ing. Supply pressure must be within the range specified
in the following table.
Inlet Gas Su
pp
l
y
Pressure
Natural Gas
Minimum: 5.0" W.C. Maximum :10.0" W.C.
Pro
p
ane Gas
Minimum:11.0" W.C. Maximum :13.0" 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.
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.
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.
Gas Manifold Pressure Measurement and Adjust-
ment (80% & 90% Single-Stage Furnaces)
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.
CAUTION
The gas pressure applies to line pressure as well and is
easily checked on the White Rodgers 36G Valve with adapter
kit # 0151K00000S.
Only small variations in gas pressure should be made by
adjusting the gas valve pressure regulator. The manifold pres-
sure must be measured with the burners operating. To mea-
sure and adjust the manifold pressure, use the following
procedure.
WARNING
HIGH VOLTAGE
D
ISCONNECT
ALL
ELECTRICAL POWER AND SHUT OFF GAS SUPPLY
BEFORE SERVICING OR INSTALLING.
1. After turning off gas to furnace at the manual gas shutoff
valve external to the furnace, remove burner compart-
ment 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
as shown in the following figure.
M
a
n
o
m
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t
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r
M
a
n
o
m
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r
H
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High Fire Regulator
Adjust
Regulator
Vent
Measuring Manifold Gas Pressure
(36G54 Valve)