I have a Thermospas Lexington tub that worked fine last fall.. I had it drained throughout the winter, have refilled it, and have no heat. When I first refilled the tub, evidently some air was trapped in the lines, as I got the FLO error. I've bled the air out of the lines, and have gotten both pumps to work.. am not seeing any error messages other than 'COOL', and still have no heat. The heat light comes on, there seems to be normal pressure from both pumps, but the water's still ~72 degrees. The hot tub is on a 240v outlet and normall heats very quickly.. I've tried resetting the breaker, no difference. The user manual only lists remedies for issues where the heat light will not come on. I have a good multimeter, but the heater elements are seemingly self-contained, and there isn't very good troubleshooting info listed. If anyone has any common remedies for issues like this or next troubleshooting steps to try, I would very much appreciate it.

Thanks,

Vince Clortho
Keymaster of Gozer

While the tub shows that it is heating, measure voltage ACROSS BOTH terminals of the heater. If you have 240V, the element went south for a vacation, and won't be back.