I have a pentair mastertemp 400 for about a year now without any problems. However twice in the past week I come home from work to find the heater on in spa mode. I do not have automation. In order to turn on the heater I have to manually push either pool or spa mode on the unit. I do have a pentair variable speed pump that turns on in the morning and cycles through different speeds for approx 8 hours. I have security cameras and verified that no one touched the heater controls. Thoughts?