I bought a used 1995 Sundance spa, I filled it and it worked fine. But it leaked. The repair guy had me stand it on end, control up, so that he could find the leak and work on it. IT was up on end for a couple of weeks while he ordered parts. Now it still leaks and the control panel shows an error of "hot". But the heater will still come on. It does show it is running the air also, although that pump does not work (it never did since I bought it). He brought over a new control pane and that shows the same error message. All the pumps work and the thing is heating for now, He also by passed the heat sensor and the spa limit switches with no luck. He says he will stand by the fix of the leak and go back and do it right, but now trying to decide how much to put into this lemon.
any thoughts on why the error message?
Before any repairs to the leak was attempted they had me try a bottle of stop leak with no luck.
It is a 1995 Sundance cameo with much of the plumping replaced.

In the future, don't ever use the stop leak... bad bad bad bad stuff! Rarely does it ever work, and it's designed to plug small holes, and it doesn't know the difference between jet parts and leaks. A "hot" error would indicate that the circuit board temperature itself is over limit. This will try to turn the blower on to circulate the air in the cabinet (hence the reason it shows your blower is on). I had that problem a while back, but right now I don't recall the correction to it. If I can recall it, I will post again, until then, use this information to start checking out that control panel.

Thank you very much for replying, based on the other reading I had done, I agree it is in the circuit board. It is not overheating as this stays on, even thought I turn the tub off for days, when I turn it back on, I instantly get the error message. The stop leak was a last resort sort of thing. I bought a used lemon of a tub and didn't want to spend much more money on it. Lesson learned. The local spa dealer claimed he had 2 out of 3 work for him with it.

I hope you remember what it was as, my local guy is stumped. I guess it is still working though, so thankful for small things.

pcb thermistor reads 82 degrees celcius and turns blower on to draw airflow through equipment bay in attempt to cool the circuit board
if its not that hot and still doing it, there is no official fix i know of other than pcb replacement