Leak from either outlet pipe or adjacent filter cap ?

When you flush the WC the water level rises up higher than normal in the machine and is coming out of the vent pipe.
The machine is switching on late, remove the motor unit and check the condition of the rubber membrane if distorted or brittle replace it and it should be OK.

Also ensure the filter is clean and vent is clear before opperating the machine

Muncher
November 2014