have Coleman Spa. The Sensors have been checked , work fine. My topside control board says it was the sensor. but it is fine. I would press button and you would hear a click then a humm and then no sound. motor would not do any thhing. I put a hose into fiter housing to get air out. then it worked fine for a while. then stopped. local company said i may have had a power surge and hurt the spa control inside the main box. I will refill tub to try to make sure air bubble is out of heater element, then what?