We have a 1999 Hot spring Sovereign. The hot tub is set in summer mode and 80 degrees temp but its so hot you can't even set in it. The thermometer we got in it almost read 120 degrees. It also kicks on and off by itself alot we unplugged the aux. wire but didn't help.

The tub may be getting too hot from the jets running too much (on their own).

Was the water already too hot when you put it in summer mode? If so it will probably still not cool down enough on its own. I would drain some and add cool water.

Turn power off. I would take the front control panel out (there are 2 screws under the white light shield towards the top) Then pop the black cover off from the back of it. Then very slightly loosen the four screws that are in the corners. Maybe 1/4 turn.

If they are too tight then the jet button mat be too close to the back panel, and the slightest expansion/contraction of the plastic may cause the jets to come on/off.

If this doesn't help you may need to change that main control panel (just the back piece with the four screws).

Thanks for the help everything's working great now.

I have a morgan spa overheating as well to 140 degrees. Any suggestions?

Thanks

overheating issue here as well just got a new everything (heater pump control pack blower) but still have old topside controls. when i turn the unit on it will heat until hi limit goes off. this makes water to hot to even get in. if i turn it down and try to set it at the appropriate temp level the unit wont kick on if it's temp drops below this limit. i know this is a thermostat issue but which one the actual thermostat that measures the water temp or is it a problem with the topside control. i can't believe it would be the actual thermostat measureing water temp as it is brand new.

any help out there with ideas.