How to Fix / Troubleshooting

Safety: Unplug the unit. The compressor and surrounding tubing can be very hot; allow cooling time.

Steps:

Check ventilation: Ensure the unit has adequate clearance from walls and that the exhaust hose (for portables) is not kinked or excessively long.
Clean condenser coil: Remove rear panel and clean dust and lint from the condenser fins.
Verify condenser fan: Confirm that the condenser fan motor runs whenever the compressor is on. Replace the motor if it is not running or is very slow.
Electrical check: Use a multimeter to verify supply voltage is within the specified range. Low or high voltage can cause compressor overheating.
Compressor health: If H3 recurs despite good airflow and voltage, the compressor may be failing internally. This requires professional sealed-system service.

Unit displays H3 and shuts down compressor; fan may continue.

Possible Causes