Danfoss
Blower or Inducer Motor Bearing Wear
Furnace produces a high-pitched whine or screeching noise during operation
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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
Worn blower motor bearings, failing induced draft fan bearings, blower wheel rubbing housing, loose motor mount
How to Fix / Troubleshooting
Safety first: Turn off power before touching any moving parts. Do not run the furnace if metal-on-metal noises are present.
Steps:
- Identify noise source: Remove access panels and briefly run the furnace to determine if the noise comes from the main blower or the induced draft fan (keep hands clear).
- Inspect blower wheel: With power off, spin the blower wheel by hand. Listen for grinding and check for contact with the housing. Tighten set screws and reposition if needed.
- Check motor mounts: Ensure the motor mounting brackets and rubber isolators are intact and tight.
- Plan for motor replacement: If bearings are noisy or seized, the blower or inducer motor should be replaced with the correct Danfoss-specified motor by a technician.
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Repair Difficulty
Hard
4/5
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