The display seems to flash in order 4-0-1 one number at a time, our temperature we have it set at 104 over and over again. The hot tub seems to be functioning properly, the water is heated and both sets of jets work. I took a video of the error code but it won’t let me attach a video. I’m thinking water might have frozen in the display panel?
It’s been doing this for over a month now. You can lower the temperature and it will then flash 2-0-1 etc. I am having trouble checking if it’s in winter mode f3. When I hold down the – and 1 button it’s hard to cycle through the options. Sometimes I can get the u error code. But can never seem to adjust it or move it past this option. When I just tried it right now after I hold the buttons for 3 seconds I seem to get a flashing = sign in the middle display. We just replaced the Uv bulb in end of October but we had been having this error code before that happened.
We have a sundance hot tub-Hawthorne 680 series. It would have been bought in 2011 or 2012 at your aqua tech store.
Let me know if you have any suggestions for me to try.