Heater Automatically Turning on and Changing to Spa Mode

[snookums]

Our Pentair Mastertemp HP heater (installed 2017) has become possessed. Over the past week, it started automatically shifting to spa mode and setting the temperature to 272 degrees, or something crazy like that. We re-set all the temperature settings, but it seems to shift back to spa mode / 272, whenever the equipment turns back on in the morning. Today, we turned the heater off while equipment was running - and within a couple of hours, it turned back on itself - and shifted to spa mode / 272 degrees. Thankfully, it has not yet raised the pool temp to much above 90. Has anyone seen this before? Any idea what is causing this?

 

[JamesW]

Probably a bad membrane keypad with a stuck "Spa On" button.

Replace the keypad membrane pad.

The 272 is probably the stack flue sensor temperature, which is displayed when the On button is held down.

 

[JamesW]

 

[snookums]

Thanks James! We'll check that out.