Checking Main Burners; Checking Orifices; Checking Gas Pressure - Maytag Goodman GM9C96 Service And Troubleshooting

SERVICING

CHECKING MAIN BURNERS

The main burners are used to provide complete combustion
of various fuels in a limited space, and transfer this heat of
the burning process to the heat exchanger.
Proper ignition, combustion, and extinction are primarily due
to burner design, orifice sizing, gas pressure, primary and
secondary air, vent and proper seating of burners.
34.5" Burner
D ALL G
ISCONNECT AS AND
In checking main burners, look for signs of rust, oversized and
undersized carry over ports restricted with foreign material,
etc, burner cross-over slots should not be altered in size.

CHECKING ORIFICES

*M9C96/*C9C96 model furnaces have factory installed #45
natural gas orifices (except *M9C960303AN which has #50).
The only time resizing is required is when a reduction in firing
rate is required for an increase in altitude or a furnace is being
converted for use with LP gas.
Orifices should be treated with care in order to prevent
damage. They should be removed and installed with a box-
end wrench in order to prevent distortion. In no instance
should an orifice be peened over and redrilled. This will
change the angle or deflection of the vacuum effect or
entraining of primary air, which will make it difficult to adjust
the flame properly. This same problem can occur if an orifice
spud of a different length is substituted.
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ISCONNECT AS AND
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WARNING
E P S
LECTRICAL OWER UPPLY.
WARNING
E P S
LECTRICAL OWER UPPLY.
1. Check orifice visually for distortion and/or burrs.
2. Check orifice size with orifice sizing drills.
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
Gas Pressure Test
The line pressure supplied to the gas valve must be within the
range specified below. The supply pressure can be measured
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.
INLET
Gas Valve On/Off
Selector Switch
White-Rodgers Model 36J54 (Two-Stage)
A
GAS
STREAM B
DENT OR
BURR
GAS
STREAM B
OUTLET