Cal J502.. We use it mostly weekends. We normally turn the temperature to 80 until we use it, (It usually goes down to around 96) and then we heat it up to 100.. Once it gets to 100, we turn the jets on, and twice it has given an flashing OH (overheat) error code. Then if I turn off and on the breaker, it gives me a SN code. (service). I then turn it off, and after it cools off for a while, it then works normal. It has happened twice at night. During the day it seems to work well. I'm thinking sensor, but then it should break down everytime it hits 100. I noticed the water was just over the filter, I wonder it was too low. Any ideas?? Thanks...