Pentair Probe Thermistor Defrost Sensor

If your heat pump is displaying a specific sensor-related error code or failing to engage the defrost cycle during cold weather, the thermistor is often the culprit. A quick diagnostic check with a multimeter can confirm if the sensor is sending an incorrect resistance reading to the control board.

No, this specific part is engineered for Pentair UltraTemp and ThermalFlo models. Always verify your specific heat pump model number against the part number 473665 before purchasing to ensure a proper fit.

Yes, the 4.42-foot length is designed to match the original factory specifications for UltraTemp and ThermalFlo units. It provides sufficient slack to route the sensor to its mounting location without needing extensions.

If you are comfortable working with basic electrical components and have experience opening your heat pump's service panel, this is a straightforward swap. However, if you are unsure about handling internal wiring or accessing the control board, it is safer to have a pool technician perform the replacement.

A faulty sensor can cause your heat pump to misread the ambient temperature, which may lead to ice buildup on the evaporator coils. Over time, this can force the compressor to work harder, reduce heating efficiency, and potentially cause permanent damage to the unit.