Dear All,
first time I have looked inside a Saniflo; mine was not turing off.
Discovered the pressure operated micro-switch was faulty, not clicking, baciscally shorted out. It may have got damp and water perhaps caused it to fuse "shut"...
Anyway, I notice the switch wire appears to be deliberately poking down towards the base of the unit, and if the wiring get's damp due to a small leak, it's quite likely it would trip the RCD/ELCB...
So it sounds to me like the switch or diaphram has failed, maybe it's too full of water and diaphram switch is faulty, perhaps water has got in through the top seal... The Diaphram pressure switch isn't designed to be kept under water.
Get a wet/dry vacuum cleaner and be prepared to suck up waste water etc, then you are ready.
So the unit needs opening up, remove the pump/switch unit complete, just 3 screws need undoing. Unclip the diaphram and carefully prise open the case where the plunger/diaphram meets, pull it open from the base, examine the micro-switch with a multi-meter and visually.. if switch still "clicks" and makes good electric circuit when pressed in, it's the motor that's faulty. if not, it's the switch. The Micro-Switch is easy to replace, and you can get one from eg maplins.
I'd guess that the diaphram and other switch parts are available as spares.