Most lightly you need a new diaphragm or micro switch fitted a standard cherr micro switch from RS would work or buy them from Saniflo, the membrane deforms and looks like a cauliflower or goes crispy, If you pull the motor assembly from the case and press the membrane if you can hear it clicking then you may get away with a membrane.
Muncher
April 2021
my saniflo plus leaks thru the top lid when flushed, what is wrong
bob
March 2010
the on/off switch works by a large diaphram pushing onto a micro switch (water one side and the micro swirtch in a sealed cavity the other side). there may be dirt under the diaphram (its very close to the bottom), or the diaphram has crud built up on it making it stiff and holding it up. remove the whole unit and strip it. the hardest bit is getting it out. a jet wash does a good job of cleaning the inside once it is out and the top is off. as can be imagined its not a pleasant job, but a heck of a lot cheaper than buying a new one
steve w
February 2010
when it is in use sound like rattling noise
bharat chauhan
September 2009
Non return valve could be stuck open or the switch could be stuck on
www.city-handyman.co.uk
steved
June 2008
sounds like the none return valve on the out let pipe could be stuck open. this would mean that any pumped waste can flow back into unit giving it the impretion that it needs to operate .