GL235 solar controller question

[ddlong131]

Just installed a solar heating system - Heliocol panels with a Hayward GL235 automatic controller. System is working as expected except that the controller is shutting off the solar loop when water temp reaches about 82.5 degrees no matter what the controller setpoint is set to. I checked the voltage levels at the sensor input terminals and they looked OK- collector temp was well above the pool temp and setpoint was well above pool temp. Conditions should have caused controller to engage solar loop.

Any suggestions as to what might be wrong?

 

[Bama Rambler]

I don't see anything in the manual about that. You don't have the sensors switched do you?

 

[Isaac-1]

Did you use official Hayward temperature sensors, or 3rd party ones? If 3rd party ones, they might have the wrong slope to them (4.0 instead of 4.4 %/degree C) making the unit think it has hit its max temperature rating. This is just a guess, but I do know I have seen several ebay vendors selling these not exactly compatible temperature sensors. Also did you extend the wire used to make the temperature sensors reach, if so what type of wire did you use?

Ike