GM9S80 Service Manual
SERVICING
35
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1. Remove burner compartment door to gain access to
the induced draft blower motor.
2. Disconnect the motor wire leads from its connection
point at the induced draft motor.
3. Using a ohmmeter, test for continuity between each of
the motor leads.
4. Touch one probe of the ohmmeter to the motor frame
(ground) and the other probe in turn to each lead. If
the windings do not test continuous or a reading is
obtained to ground, replace the motor.
5. If the windings have a continuity reading, reconnect
wires. Turn power on to the furnace and turn the ther-
mostat on in the heating mode. Check voltage for
115V at the induced draft motor terminals during the
trial for ignition. If you have 115V and the motor does
not run, replace the induced draft motor.
6. After completing check and/or replacement of induced
draft motor, reinstall burner compartment door.
7. Turn on electrical power and verify proper unit operation.
A combination redundant operator type gas valve which pro-
vides all manual and automatic control functions required for
Single stage gas valves should be tested on the furnace with
24 VAC connected to the gas valve and manometers read-
ing supply line and manifold pressures.
The main burners are used to provide complete combustion
of various fuels in a limited space, and transfer this heat of
secondary air, vent and proper seating of burners.
In checking main burners, look for signs of rust, oversized
and undersized carry over ports restricted with foreign ma-
terial, etc, refer to previous drawing. Burner cross-over slots
must not be altered in size.
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as shown in the following drawing.
No resizing should be attempted until all factors are taken
into consideration such as inlet and manifold gas pressure,
of the gas being consumed.
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ing rate is required for an increase in altitude.
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wrench in order to prevent distortion. In no instance should
1.
2.
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cal size and angle with proper drill size opening should
be installed.