Carrier ComfortLink Alarm 63 – Compressor Lockout Causes

What Does Alarm 63 Indicate?

Alarm 63 generally indicates a compressor protection lockout due to repeated fault conditions.

The controller has detected abnormal operation and has disabled the compressor.

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Common Causes

• High head pressure
• Low suction pressure
• Phase imbalance
• Overcurrent condition
• Repeated pressure switch trips

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Troubleshooting

1. Inspect refrigerant pressures
2. Check condenser coil cleanliness
3. Verify fan operation
4. Inspect electrical connections
5. Check overload protection devices

Correct root cause before resetting.

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FAQ

Will resetting fix it permanently?
No. The underlying fault must be corrected.