I have a 1999 Marquis Coastal Series tub. Everything seems to work just fine, except after the tub reaches the set temp, the heat light turns off and it continues to run beyond the set temp. It's gotten up to 106 while set at 80 and then I just turned it off. Also, the filter cycles seems inconsistent. I have it set for 1 hour 2x/day, but it seems to run more than that.

When the tub was at 106, I measured it with another thermometer and it was 106. The fact that the heat light turns off when it reaches the set temp tells me the thermostat is okay.

Does anyone know what may be causing this and are there any troubleshooting ideas? Thanks!