Vacuflush pressure switch issue

[32carv]

New to me boat with vacuflush head. Pump turns on when flushed sometimes and not others. If I tap on pressure switch with screwdriver it will kick on. I plan on replacing the seal on the toilet and 4 duck bills. Do I also need to replace the pressure switch?
Jim

 

[capt6650]

Depending on how old the pressure switch is it may have to be replaced. The switch works by having a rubber diaphragm pulled in by the vacuum which moves a plunger away from a button.

Over time this rubber diaphragm can get hard, either from lack of use or just from age. As the rubber gets harder, it doesn't move enough to either activate the switch or sometimes to close the switch.

If you haven't used the head in a while, sometimes you can get the switch to work by gently pushing the plunder that sits below the switch in and out. You can also try adjusting the thumb screw on the plunger which adjusts how much vacuum is required to turn the switch off and on.

I found that the switch had to be replaced about every 7-10 years if it was used often. More often when it was not used for long periods.

 

[32carv]

Boat is new to me. Previous owner said he didn't' use it much. Boat is 2006 and I assume switch is original but not sure.
Jim

 

[Nautiville]

Last year we had to replace the main diaphragm on the vac pump. We (well actually wife did it, I couldn't fit in there.. she wasn't happy, but she's a trooper!) We went ahead and did all 4 duckbills, the pressure switch and the main diaphragm (actually changed to the quiet pump,) It's not a pleasant job, but worth getting it all done at the same time and off the list. Pressure switch was the easiest out of the replacement of parts.