The Saniplus has a limited run time so will overload and stop depending model the French ones were around 7 min, If the Non return valve is faulty it will run on pulsing and you can here the water running back into the box but if there is a blockage in the machine or pipework it will run on continously if the membrane \ Microswitch requires replacement it will run on again without pulsing ( Try Tapping the case at the bottom on the same side as the power cable if it stops it's the membrane ) best to do a buckett Test on the machine i.e. discharge the machine via it's flexible hose into a bucket if it finishes its cycle then there is not a blockage and you can check the Non Return Valve functions correctly if it is ok move on & check the membrane if it looks like a Caulliflower for want of a better word replace it and check the Microswitch is ok Whilst you have the lid off the machine give it a clean out check the anti cavitation hole at the bottom of the machine by the discharge hockey stick it has to be clear.
If all else fails ring your local service agent.
Please turn off the machine and isolate it from the Electrical supply better still unplug it totaly before working on this machine IT can and will BITE if you are stupid or careless !!!!!!
God did I really Repair 800 to 1000 Saniflow machines a year !!!!!
Mike, October 2009