I just replaced the heater on my sundance Spa. When I turn the spa on at the breaker the controller kicks on for a few seconds reading 110 dergrees OH and kicks off. The water is actually ice cold. Sounds like a sensor but which one.

Is there any error messages on the topside. What do you mean by kicks off.

The OH (over heated) error message shows up for a second and then the panel goes blank. The breaker does not flip. The control panel light is on but absoutly nothing is on the screen. Its like the spa shuts itself off.

Sounds like the Temperature Sensor (which is located in the filter well of your spa) has gone bad. It looks like a little plastic bolt mounted in the side of the filter well of your spa. There's freon (or some kind of temperature expansion liquid in it) and when it goes bad you will get an "OH" (overheat) message even though the water is cold. The tub shuts itself down as a safety precaution (called WatchDog mode on Sundance Spas).

I just had the exact same problem: I replaced the heater on my 2000 Sundance Marin and was getting the same OH message and shutdown. I bought a new temperature sensor online for about $60, and replaced it myself (pretty easy and basic), and the tub started up and heated up just fine. You will have to drain the tub halfway though, so there isn't any water in the filter well.

After replacing mine, it now appears that I have a bad Hi-Limit/Freeze Sensor as well, because the tub constantly displays the "ICE" warning message even when the water temperature is 100+ degrees... so the heater and pumps run continuously until it eventually overheats and shuts down. Apparently the sensors are supposed to be replaced all at once?!

Good luck with the temperature sensor, hope it goes well.

Thanks! I will give it a try.

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I replaced my temp sensor too, but I didn;t drain the tub down before hand as I realize now I should have. SO when I opulled the sensor out the water started to empty down the feeder tube and water got all over the, now I can't get the spa to start up...the circuit keeps popping out when I reset it at the house panel....I have no idea what to do now...you have any suggestions???

Thanks
quote="MikeH482"]Sounds like the Temperature Sensor (which is located in the filter well of your spa) has gone bad. It looks like a little plastic bolt mounted in the side of the filter well of your spa. There's freon (or some kind of temperature expansion liquid in it) and when it goes bad you will get an "OH" (overheat) message even though the water is cold. The tub shuts itself down as a safety precaution (called WatchDog mode on Sundance Spas).

I just had the exact same problem: I replaced the heater on my 2000 Sundance Marin and was getting the same OH message and shutdown. I bought a new temperature sensor online for about $60, and replaced it myself (pretty easy and basic), and the tub started up and heated up just fine. You will have to drain the tub halfway though, so there isn't any water in the filter well.

After replacing mine, it now appears that I have a bad Hi-Limit/Freeze Sensor as well, because the tub constantly displays the "ICE" warning message even when the water temperature is 100+ degrees... so the heater and pumps run continuously until it eventually overheats and shuts down. Apparently the sensors are supposed to be replaced all at once?!

Good luck with the temperature sensor, hope it goes well.