Pentair Ultratemp - Water Therm Open error

[outatime]

Hi All

All of a sudden my pool heat pump has quit working, I am getting the error message "Water Therm Open" , I thought it might be a thermistor so I replaced that but it's doing the exact same thing. Anyone else know what might be the issue please? says my pool temp is -27 degrees right now which is off by a lot! Maybe in the 70s if I had to guess.

Thank you very much

Stuart

 

[ajw22]

How old is the HP?

It is either the thermistor or the board.

A reading of -27 says the board is seeing a resistance of 210,716 instead of 10,000 at 77 degrees.

You can get a 10K resistor and connect it where the temperature sensor connects and see what your heater reads. If it reads 77F then your sensors are bad. If it reads something different then your board is bad.

Temperature Sensors - Further Reading

www.troublefreepool.com