I recently replaced my high pressure switch. It was leaking profusely and corroded. It wasn't working.
The desal unit will work fine without the switch in the system. It is there to prevent over-pressurization.
The new switch came with some installation instructions. The switch comes pre-set at a very low cut-out pressure.
The instructions tell you to "Install the switch, start up the desal unit and increase the high pressure knob until the high pressure pump cuts out. Note where the cut out happens on the hi-pressure scale. Repeat until the cut-out occurs at the top of the green zone on the hi-pressure gauge." This procedure is hard on the generator and high pressure pump. I inquired to the Dessalator techs as to why they could not supply the switch preset at some value of 800-850 PSI which is the industry standard for these pumps and also why a numerical pressure gauge is not fitted or recommended as a refit. No answer has been forthcoming as yet.
Cloudstreet SM2K 331