Outdoor unit contactor chattering, buzzing or pitted contacts
Chatter is usually low or unstable 24 V at the contactor coil, not the contactor itself. Pitted contacts are a wear failure that causes voltage drop, heat and hard starts. Measure coil voltage under load and voltage drop across closed contacts.
Single source ~40 min moderateBrands: All
Before you start
- Line voltage (240 V) is present at the contactor: turn off the disconnect and verify 0 V before touching.
- Discharge capacitors before removing wires.
- Live readings only with insulated probes and one hand.
Diagnostic steps
Unlock all 8 steps with expected values
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