We just filled our new hot tub with water.
The pumps work but we have been waiting for the water to heat.
The temperature has not changed. It is still about 78 degrees. The LED display shows three flashing lights with or without the pump on.

The manual identifies the problem as:
If three flashing dots appear below the temperature display while there is no pump operating, turn the pump on. If the three flashing dots went away this indicates that the pressure or flow switch was activated although there was no water flow.
So we turned the pump on. We still have the three flashing dots.

With the pump on the error message reads:
If three flashing dots appear below the temperature display while the pump is operating, turn the pump off. If the three dots went away this indicates that the pressure or flow switch was not activated although there was water flow.
So we turned the pump off. we still get the three flashing dots.
So far turning the pump on and off does not work.
Where is the pressure and or flow switch?
How do you activate it? or deactivate it?

I don't know if you still read this site or if your question ever got answered. It sounds like you have a pressure switch problem and it just needs an adjustment. Or you can try to reset your breaker, sometimes that works.