94 Soverign Overheating

[cubsno1]

So the other day I dumped and refilled my spa.. (94 Hot Springs Soverign).. today I went back out to throw some more dichlor in there to get my CYA up and the thing was pegged on my floating thermometer. It had to have been 150+ degrees. Obviously I unplugged it, but don't have any idea where to start?? The thermostat is not working, and I believe there is some sort of hi-limit thermostat as well that's not working. I'm familiar with the mechanics of the tub but not so much the electric logic. Any hints?

Thanks,
Tom

 

[y_not]

Most heaters use snap discs that open and close at certain temperatures. Look for these, they can be tested with an OHM meter, or that setting on a multimeter.