I had a problem with my GFCI tripping and , and had the techs out and they said I had a bad breaker. I replaced the breaker and the tub then was able to power up. I still can not get the tub to heat even though I have flow. I replaced the heater element, and apparently that is not hte problem either. I assume that means that I probably have a problem with the pressure switch, but how do I check it/adjust it, or can it be something else?

It is a California Cooperidge spa that is only about 4 years old, 240v.