Sanitary pump trouble shooting.

Maybe, depends on the supply... If there is a tank that the pump takes suction from, then you will probably have a level control that causes the pump to turn on when the level gets high enough. In that case, the float may be stuck, or perhaps you have a toilet constantly running that keeps it going.

Have you checked it in the middle of the night when everyone is asleep? Does it run then?

That will depend on the design. A small reservoir would require a big pump with a lot of switching. On a big reservoir the pump can be smaller.

Rather spend some money and have the pump and installation checked.

Hendrik,

What are the chances our guest ever comes back? Oh well...

..............or guests get their own back!!!!!!

I don't think a ball valve is ideal for this situation, electric or electronic pump start and pump stop controls are better; maybe you have a malfunction on this side of things..........of course dependent on what is fitted.

I hope guest did not crawl into the crawl space.

could be sucking air through a gasket. could be a clogged filter letting waste through only a little bit at a time. Could be a valve downline whose seat has corroded loose from the stem and is now blocking passage of fluid. The crap people put down a toilet, it could be a phalanx of army men who have set up a perimeter around the drain, preventing free passage of waste. Something (like a pair of panties) could be stuck in the impeller.

I'd say no, it isn't normal for a sanitary pump to run constantly but there are a thousand reasons why it would happen, none of which can be checked for without shutting down and partially opening the system.

No. There are several possible causes. Your level switch may be malfunctioning, your pump circuit breaker may be jammed in running condition, water could be leaking in from somewhere keeping the tank continuously at high level etc.