Ecm Tm 2 Variable Speed Furnace Motor Quick Check - American Standard *UD Series Operation Manual

ECM TM 2 Variable Speed Furnace Motor Quick Check
Blower Motor Will Not Run
1. Jumper 24 Volt A.C. "R" terminal to "G" terminal on
the Motor Control Board.
Does motor run?
No: Go to step number 2.
Yes: Motor runs, check thermostat and thermostat
wire.
2. Unplug 16 wire low voltage harness from the
motor control board. Jumper 24 Volts A.C. to pins
12, 15 and common pins 1 and 3.
Does the motor run?
No: Go to step number 3.
Yes: Go to step number 5.
3. Unplug 16 wire low voltage harness from the
motor. Jumper 24 Volts A.C. to motor low voltage plug
pins number 12 and number 15 and pins number 1
and number 3 which are common.
Note: Test plug can be made from a good harness to
simplify this check.
Does motor run?
No: Go to step number 4.
Yes: Fault is in the 16 wire low voltage harness.
Repair or replace it.
4. Is the line voltage to the motor high voltage
power plug pin 4 and pin 5 correct?
Furnace ECM TM 2 motor correct voltage is 120 Volts
A.C. and there must be a jumper wire in this plug
between pins 1 and 2.
No: Correct line voltage fault.
Yes: Line voltage correct and motor will not run.
Replace motor.
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