Hello everyone,

I have a Grundfos SoloLift2 WC1 on a toilet and since a few months the impeller keeps getting stuck.

I was quite happy to unblock it myself using the service shaft above the motor and a long screwdriver, but it keeps happening roughly once every month.

When stuck, it makes a humming noise then stops. Nothing turns.
When I unblock the grinder by hand it's very hard to turn and I have to turn left, right, left again until it finally gets free. Then it runs fine.

I do not put anything I shouldn't down there. And these machines do not require service.

What could the cause be and what should I try first ?

Thank you