If I understand your trouble shooting process, when you take the high pressure switch out of the circuit by disconnecting the wires to that switch, the unit will run for about one hour, making good quality water (as measured using a hand held TDS meter) but then will shut down and gives a red light at the control panel. Is that correct?
I want to confirm that when the shut down occurs it isn't due to a circuit breaker opening. Correct?
Gary S. Silver
Amel SM 2000 #335