Temperature Sensors - Further Reading

Temperature Sensors

Standard 10K Thermistors

Pentair 10K Temperature Sensor.jpg

Temperature sensors for Pentair, Hayward, Jandy, and other automation are standard 10K ohm thermistor sensors. They are used for air, water, and solar temperatures.

Temperature sensors in other pool equipment also use 10K thermistors, including:


The sensor can be tested with a multimeter. It should read 10,000 ohms at 77F (25C) degrees. You can lookup other test values in the Temperature vs Resistance Conversion Chart for 10k Thermistors.

To test the device a 10K ohn resistor can be plugged in in-place of the thermistor cable and the device should read it as 77F (25C) degrees.

Hayward Pool Boss system

The temp sensors (PSC2023 and PSC2022) on the Hayward Pool Boss system are not 10K thermistors.[3] They are Negative Temperature Coefficient (NTC) thermistor where the resistance goes up when the temperature goes down. The span of readings at normal pool temperatures is more than 200K Ohms.[4]

Hayward said the unit was made by Balboa. The Balboa M7 unit looks almost exactly like a direct replacement for the PSC2022 Hayward part except that the wire is 2 feet long instead of 20 feet long.[5]

The Balboa 25-175-0337 is a combined water and air temp sensor with two wires zip-tied together at the board plug end and two probes that look suspiciously just like the Hayward parts. Both of these sensors work and track temps just like the Hayward parts.