ken2112

So I already replaced the temp sensor with same results, so I guess I will replace high limit sensor as well and see if that corrects it.

The wire goes uninterrupted from probe to circuit board. I will have to check on foam covering on hi limit probe. I was told by a tech that the high limit sensor really doesnt have anything to do with spa water temp reading, just as a shut off if heater temp gets too high. Is he wrong?

Yes i have an electrical tester. I'll switch them later today and see what happens.

I used a high quality digital thermometer on it. It says its 99 degrees, plus you can feel the difference when in the water between 104 and 99. There is no error code being thrown. The hot tub was always spot on with display temp and water temp till just recently. Now i can't get water to go above 100 since it thinks its at 104 and shuts off heater.

I've used 2 different thermometers and they both say hot tub is about 99 degrees. On the 2 sensors one is for the hot tub water and I thought the other one was the high output temp sensor that's in heater. Are you saying I should switch those 2?

So my 2006 jacuzzi j355 has been misreading water temps by 4 to 5 degrees. So when control panel reads 104 it's only 99 to 100 degrees in hot tub. I replaced temp sensor and it still does the same thing. Is this a control panel problem then?