Unsuccessful defrosting — Defrost conditions not met or repeated failures

What does 83 mean?

The Heat Pump has failed to complete its defrost cycle. This can happen if defrost stop conditions are not met for an extended period (F750) or if multiple defrosts occur in a short timeframe (F110). The compressor and immersion heater will be stopped.

• Excessive ice buildup on the outdoor unit's evaporator coil.
• Faulty defrost sensor or control logic.
• Low refrigerant charge or other system inefficiencies.
• Outdoor unit fan malfunction, preventing proper airflow for defrosting.

Click steps to track your progress.

1. 1

   Visually inspect the outdoor unit for any heavy ice buildup on the coils or fan. If safe to do so, carefully remove excess ice (e.g., with warm water, not sharp objects).

2. 2

   Ensure there are no obstructions around the outdoor unit blocking airflow.

3. 3

   Power cycle the Heat Pump by turning it off at the main breaker for at least 30 seconds, then turn it back on.

4. 4

   If the alarm recurs frequently or the unit remains iced, contact a qualified NIBE service technician for a thorough inspection.