Pentair Pentair UltraTemp Heat Pump Pool Heater dF Error Fix: Defrost Mode

Error code dF on the Pentair Pentair UltraTemp Heat Pump Pool Heater means: Defrost Mode. The heat pump is in defrost mode. This is a normal operating cycle, not an error. When operating in heating mode in cooler weather, the evaporator coil extracts heat from the air and can accumulate frost or ice. The defrost cycle temporarily reverses the refrigerant flow (switching to cooling mode briefly) to melt ice off the coil. The fan may stop during defrost on some models. The cycle lasts a few minutes and then returns to normal heating. If the heat pump seems to be defrosting excessively (every few minutes) or the coil is heavily iced, there may be an underlying issue such as low refrigerant, a faulty coil sensor, or inadequate airflow.

The most successful fix is "Test and Replace Faulty Coil Temperature Sensor" (medium difficulty, ~45 minutes). Estimated DIY cost: $10-$25. HomeMD has 2 community-ranked fixes for this error.

This error is rated info severity. It is generally not urgent and can often be resolved with a simple DIY fix.

Yes — the top-ranked community fix ("Test and Replace Faulty Coil Temperature Sensor") is rated medium difficulty and takes about 45 minutes. Tools needed: T20 Torx screwdriver, Digital multimeter.

DIY cost: $10-$25. Professional repair typically costs $150-$250. Many homeowners save money by trying the top-ranked community fix first.

The Pentair Pentair UltraTemp Heat Pump Pool Heater has 8 other known error codes, including: E01 (Water Temperature Sensor Fault), E02 (Coil Temperature Sensor Fault), E03 (Ambient Temperature Sensor Fault), E04 (High Pressure Switch Tripped), E05 (Low Pressure Switch Tripped), and 3 more.