Flashing display screen

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.

Lindsey Acheson


  1. Nigel


    Good morning Lindsey. You could have a bad Topside control panel or a bad PWA (motherboard). Try checking your connections from where the topside panel attaches to the PWA. Make sure the connection at the PWA is secure. Also check the cable from the PWA up to the topside for any breaks in the insulation. If the connections are good I would try a new Topside panel first. If you require a new topside panel send me your current email and I can send you a purchase link.

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