just had mine fixed, having replaced the pump and cleared the pre filter of romanised coins lol!
turned out to be a damaged heater element, engineer removed a bra underwire - i'll be having words with the better half later, all the kack i've had my fault and on about screws and coins left in my pockets (i only ever use a girdle ;0).
replaced element all working fine also removed anti siphon valve from wast pipe connecteor (pump already has one).
Alan, August 2010