Comfortmaker outdoor unit makes loud buzzing or humming but fan and compressor do not start
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.
Possible Causes
How to Fix / Troubleshooting
Safety: Turn off power at the disconnect and verify with a meter. Capacitors can hold a charge; discharge safely before handling.
Steps:
- Inspect capacitor: Look for bulging top, oil leakage, or rust. Replace if any signs of failure.
- Test capacitance: Remove wires and test with a capacitance meter. Replace if more than ±10% off rating.
- Check contactor: Ensure contacts are clean and making good connection.
- Attempt restart: After replacing capacitor, restore power and test.
Note: If compressor still only hums and trips breaker, it may be locked and require professional evaluation.
Repair Difficulty
Required Part
We may earn a commission from links on this page.