Question

Hello Tom, Can you help? A common enough problem it seems. run any tap in the van and you can hear the pump running on. Sometimes it will stop and sometimes we have to switch the pump off. I have tried shaking the submersible pump to get air out and also filled the pipe with water before switching on. The chattering noise we hear does not appear to come from the pump which is on the nearside but from behind the fuseboard on the offside at the very front of the under seat locker. I have read as much as I can about this and it seems that microswitches are actually inside the taps, is that always so?

Answer

It appears that your pump is controlled by a pressure switch and not microswitches. If you have a Whale Watermaster system then the pressure switch is in the water inlet housing. It can be adjusted by turning the white plastic screw that is evident on the rear of this housing. If the pump is running on then you will need to turn this screw clockwise but only a quarter of a turn at a time.
Alternatively you may have a Whale pressure switch in the cold water line close to the inlet. This has a thumbscrew on the top which again can be adjusted but only slowly.