mcHotTub

I had to trouble shoot mine today. Same as others - bad relay. My board looks almost identical to the one in this thread. If you have a multimeter, it is easy to test. http://www.backyardplus.com/testing_heater_relay_board.php has a step by step "how to test". But the short version is that you should have 220 across black/white. Do not test your black to green as in the original post, as that should kick your ground fault. My tub is "new to me", got it from a friend who was moving. It was working fine at his place, but of course after the move had to be refilled. My guess is that the relay being held open for so long to heat the water just could not take it any more. It did get it to about 90 before it died. Hose temp is about 55 right now I would guess, so that is a 45-50 degree change being asked of the heater and relay, quite a bit of work.