1 pressure switch may be faulty.
2 plastic pressure pipe SPLIT or maybe DETACHED (refit job done)
TRY NUMBER 2 +3 BEFORE CHANGING THE SWITCH
3 the pressure chamber hole ( AT BOTTOM END) that joins up onto the plastic pipe connected to the pressure switch is BLOCKED with gunge/washing powder. preventing the air pressure switch from WORKING to turn OFF the WATER
clean out the chamber hole refit the pipe try a fill
wirecutterman, September 2010
