Carrier Heat Pump error codes
6 Carrier heat pump codes and problems, each with ranked causes, safe homeowner checks and honest repair costs. Count the flashes or read the code on your control board, then find it below. Legends vary by board revision, so confirm against the label inside your unit's door.
| Code | What it means | Severity |
|---|---|---|
| Auxiliary heat on constantly | Carrier heat pump running on aux heat nonstop? Learn the causes, from thermostat setup to defrost and refrigerant faults, plus safe fixes and repair costs. | Call a pro |
| Frozen and not defrosting | Carrier heat pump iced over and not defrosting? Learn the causes (airflow, runoff, defrost sensor, board, low charge), safe fixes and repair costs. | Call a pro |
| Ice on outdoor unit | Ice on your Carrier heat pump outdoor unit? Learn normal frost vs. problem ice, the main causes, safe checks, and repair costs from $0 to $2,500+. | Call a pro |
| Not cooling | Carrier heat pump not cooling? Learn the causes, from a stuck reversing valve to low refrigerant, which fixes are safe, and what repairs cost. | Call a pro |
| Not heating | Carrier heat pump not heating? Learn the likely causes (thermostat, defrost, reversing valve, refrigerant, compressor), safe fixes, and US repair costs. | Call a pro |
| Stuck in defrost mode | Carrier heat pump stuck in defrost? Learn the causes (defrost board, sensor, reversing valve, relay), safe checks, and repair costs from $0 to $1,800+. | Call a pro |
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