Need some help. I have an older Infiniti Hot tub Not sure how old it was here when I bought the house 6 months a go. Our electic blinked and when I went out to check the hot tub it was blinking FLO. I shut the power off for 30 mins, Did no good. Any help?

be sure your circulation pump (or main pump) is running. with no pump you'll get the flo error.

How do I find that out? My main pump is working it kicks on every few hours

Royal Spa(not in business anymore)-about 12 yrs old. FLO error-I replace pressure switch-even though it was alright, replaced heater. The pump doesn't shut off after heating and the FLO comes on. When I disconnect the red wire from the pressure switch and plug it back in it works for a bit and then same thing.
Any thoughts would be GREATLY appreciated