Hi all, I have an unusual problem with my 2015 Pentair Mastertemp 250. It ignites just fine (igniter recently replaced) and brings the pool up to set temp just fine. But then, while maintaining the set temp (usually after 8-12 hours), it randomly shuts down and the Service Heater light lights up. There are no error LEDs lit on the back of the control board, and the Fenwal unit does not have anything on the LED either. It just shuts down and the Service Heater LED is lit - nothing else. If I turn the heater off and back on at the control panel, it again runs just fine for a 8-12 hours and repeats.
It seems to shut down when it's cycling to maintain temp only after an hour or two. I was wondering if anyone else has seen a similar problem or has any advice of what to look into/diagnose, as I'd rather not replace the heater that seems to otherwise work fine. Attached is the graph of temperature from my Sutro over many days. It's about 8-12 hours between the peaks and each time after the temp drops I have to power cycle the heater to restart it which gets rather tedious.
It seems to shut down when it's cycling to maintain temp only after an hour or two. I was wondering if anyone else has seen a similar problem or has any advice of what to look into/diagnose, as I'd rather not replace the heater that seems to otherwise work fine. Attached is the graph of temperature from my Sutro over many days. It's about 8-12 hours between the peaks and each time after the temp drops I have to power cycle the heater to restart it which gets rather tedious.
