aquatronic power shower?

check your solenoid valve has power to it when shower on.
or do a resistance test with a multi meter in its failed state with power off it should be 3.4 ohms or above if below its faulty.

also check the filters which are located where the hot/cold enters the shower unit.

hi-spec plumbing & heating.
May 2008

You could just have air in the pump. The whir of the pump is the centrifuge spinning via the pump motor. With air in the pump there is an inconsistency in pressure and an air-lock is formed. Also make sure there isn't any 'flow back' from your hot water source. To get rid of air... crack (slightly undo!) connections on the pump (on the outlet) and bleed out any air - do this with the shower on but set to 'COLD' water should then start to flow. Remember HOT water contains a lot of dissolved air. You could after use, run the shower with cold water only for a second or two..

Robin
May 2008