Pentair Pentair UltraTemp Heat Pump Pool Heater E01 Error Fix: Water Temperature Sensor Fault

Error code E01 on the Pentair Pentair UltraTemp Heat Pump Pool Heater means: Water Temperature Sensor Fault. The water temperature thermistor at the heater inlet or outlet has an open circuit, short circuit, or is reading out of range. The UltraTemp cannot regulate water temperature without a functioning sensor. Check the sensor connector for corrosion. Measure thermistor resistance — it should vary predictably with water temperature. Replace the thermistor if defective.

The most successful fix is "Test and Replace Faulty Water Temperature Thermistor Sensor" (medium difficulty, ~45 minutes). Estimated DIY cost: $15-$25. HomeMD has 2 community-ranked fixes for this error.

This error is rated warning 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 Water Temperature Thermistor Sensor") is rated medium difficulty and takes about 45 minutes. Tools needed: T20 Torx screwdriver, Digital multimeter.

DIY cost: $15-$25. Professional repair typically costs $150-$220. 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: dF (Defrost Mode), E02 (Coil Temperature Sensor Fault), E03 (Ambient Temperature Sensor Fault), E04 (High Pressure Switch Tripped), E05 (Low Pressure Switch Tripped), and 3 more.

Error code E01 also appears on 3 other Pentair models: Pentair IntelliFlo VSF Variable Speed Pool Pump, Pentair IntelliFlo3 VSF Variable Speed Pool Pump, Pentair MasterTemp 400,000 BTU Gas Pool/Spa Heater. The fix may vary by model, so check each model's specific page for tailored repair steps.