I continue to have my hot tub overheat and don't know where else to go. It started overheating a few months ago (OH message frequently). I replaced the filter, replaced the Hi-Limit Sensor and replaced the Pressure Sensor. In a matter of days it overheated (didn't shut off) and melted the pressure switch & fried the heating element. I finally called a tech to test it. He said the relay was stuck so I replaced the circuit board. It seem to work fine for a week or so but now I am getting the OH message again and the water is extremely hot. It has a new circuit board, new pressure switch, new hi-limit sensor, new temp sensor and new heating element.....I don't know what else to do.
Hot tub: Great Lakes
Control Unit: Balboa Value 2000

are you absolutely certain the temp sensor was replaced?

This is always a common misconception in diagnosis... tub overheats so replace the hi limit sensor -

Which is wrong.

Replace the temp sensor.

Sure that temp sensor was replaced? And it's placed in the thermowell (or where ever it was supposed to go?)

Yes-absolutely positive because when it originally started overheating that was the first thing I replaced and it continued to overheat so I assumed that it wasn't the temp sensor that was bad. Then the pressure switch was replaced, hi-limit switch, heating element and finally a new circuit board. When it started over heating again I even tried putting the old temp sensor back in since the new one didn't correct the problem.

You need a voltmeter to do some basic tests.

But for now, if you disconnect either the high limit sensor, or the temp sensor, does the system still work?

And if it works is it heating with them disconnected?

When I disconnect either sensor I then get the (sensor message)SN1 or SN2 error on the top panel and the hot tub won't even turn on. Should I just try replacing the temp sensor again? I guess what I don't understand is how the temp sensor would be making it so hot - I know it reads water temp but I don't believe its reading the temp incorrectly -the water really is that hot. Thanks for the help.

No not really - you need to test the heater to be certain that it is receiving voltage on the heater terminals while this thing is running.

My concern at this point is that you either have a defective board (again - unlikely though),

or your board (insert something that sounds intuitive here),

or something else is going on.

You need to test the voltage across the heater terminals. Nothing else you can do is going to help at this point without basic diagnostics.

Thanks will try to test to see what I come up with. Although I will tell you that when I had the hot tub repair guy come out he did test all of that and said everything was fine except the relay on the circuit board. Thanks again for your help. Do you know what the readings should be?

I need to know if your heater is actually getting power when you've got your temperature setting set down low... 220+ vac or whatever you get.