I've got an older (10 yrs) Jacuzzi brand hot tub, 7'x7'. I believe
it's a model 280, probably sold at Home Depot type stores.

After running for about 2 hours, it shuts down, and the only light on
the control panel blinks once/second. It cannot be turned back on
without cycling the main power. Then it runs, heats up etc for
another 2 hours or so.

The control panel is basic, a rotary knob for temp control, a red LED,
and a membrane push button switch that cycles between 4 settings on
each push (high, low, high/low with light). Does not appear to have
an off position.

A call to Jacuzzi tech was no help. Local hot tub/pool vendors have
no idea, and cannot assist.

Any ideas? Could this be a temp switch/sensor? Do I have a pressure
sensor on this model? Could the circuit board be bad?