Armstrong Air
Indoor Blower Motor Not Operating
Indoor blower does not run in cooling, outdoor unit runs normally
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Failed blower motor, Failed blower capacitor (PSC motors), Open blower relay on control board, Blown indoor fuse or tripped limit switch
How to Fix / Troubleshooting
Safety first: Turn off power to the furnace/air handler. Blower wheels can start unexpectedly.
Steps:
- 1. Check thermostat fan setting: Set FAN to ON. If the blower still does not run, the issue is in the indoor unit.
- 2. Inspect fuse and limits: Open the blower compartment and check the low-voltage fuse and any manual reset limit switches. Reset if tripped.
- 3. Listen for motor hum: With power on and a call for fan, listen for a humming motor. A hum without rotation suggests a bad capacitor or seized motor.
- 4. Test capacitor (PSC): Discharge and test the blower capacitor. Replace if out of spec.
- 5. Spin blower wheel: With power off, try rotating the blower wheel by hand. If stiff or noisy, the motor bearings may be failing.
- 6. If motor will not run with correct voltage present: Replace the blower motor (and capacitor if PSC). ECM motors require OEM replacements and setup.
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Repair Difficulty
Hard
4/5
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