508096-01
Issue 2037
Page 1
6
of 3
1
Blower Compartment
Each blower is statically and dynamically balanced as
an assembly before installation in the unit.
IMPORTANT
GUH80C
units are equipped with a constant torque
ECM motor. It has a DC motor coupled to an
electronic control module both contained in the same
motor housing. The motor is programmed to provide
constant torque at each of the five selectable speed taps.
Each tap requires 24 volts to energize.
Input Voltage Requirements
The circuit is designed to be operated with AC voltage. To
enable a tap requires 12 to 33VAC. Expected current draw
will be less than 20mA.
Troubleshooting the Motor
Troubleshooting the motor is an easy process. Follow
steps below.
1.
Shut off power to unit.
2.
Remove input plugs P48 and P49 from motor. See
Figure 14 for troubleshooting procedure.
If correct voltage is present in tests 1 and 2 and motor is
not operating properly, replace motor. The motor is not field
repairable.
If replacing the indoor blower motor or blower wheel is
necessary, placement is critical. The blower wheel must
be centered in the blower housing as shown in Figure 12.
When replacing the indoor blower motor the set screw
must be aligned and tightened with the motor shaft as
Figure 12.
Blower Wheel Replacement
Center Blower Wheel
in Blower Housing
Figure 13.
Set Screw
Housing Hub
ALIGN AND TIGHTEN SET SCREW WITH
FLAT SIDE OF MOTOR SHAFT
Motor
Shaft
