FLO error on 1999 Sundance Calypso

[raspyni]

I love this hot tub so much and refuse to let it go

The circulation pump runs 24/7 and FLO switch is new, tested, and I can see it closing (clear body) when the circ pump is running.

One of these two conditions are happening constantly:
1. The circ pump is running (and good output coming into the tub) with the display showing a solid FLO. None of the buttons work.
2. The circ pump and Jets 1 are running, the tub is crazy hot (112 and it's always set to 102). None of the buttons work.

Either of these conditions are temporarily fixed by flipping the subpanel breaker off and back on. Condition 1 kicks in after about 2 mins. During the 2 mins I have full panel control of both jets, the air, the light, and the temperature adjustment. If I start Jets 1 or 2, it will run the full 20 min cycle and then kick into the FLO error (Condition 1).

I'm frustrated and thinking it might be a circuit board problem but would love some way to confirm this before I shell out $600 and have the same problem.

I have checked continuity out of the flow switch and there is a connection when the pump is running.

Thank you for any guidance, links, or suggestions... I have deeply read this forum for FLO errors and haven't found this particular situation.

Barry Friedman

 

[RDspaguy]

Solid flo means the switch is reading closed when it should be open. It should only be open when the spa first starts and if it shuts off the circ pump in response to a temp reading 3 degrees above set temp.
What does the temp display show in those 2 minutes? Any OH errors? Rising temps?
Is the 112 degrees the actual water temp or the display temp?