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12. Blower Motor
IMPORTANT
Each blower is statically and dynamically balanced
as an assembly before installation in the unit.
ML180UHE 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 ve 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
Troubleshooting the motor is an easy process. Follow
steps below.
1 - Shut o power to unit.
2 - Remove input plugs P48 and P49 from motor. See
gure 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
eld 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 gure 12.
When replacing the indoor blower motor the set screw
must be aligned and tightened with the motor shaft as
shown in gure 13.
Center Blower Wheel
in Blower Housing
BLOWER WHEEL REPLACEMENT
FIGURE 12
Set Screw
Housing Hub
ALIGN AND TIGHTEN SET SCREW WITH
FLAT SIDE OF MOTOR SHAFT
Motor
Shaft
FIGURE 13
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