So just to double check theres nothing at all comming on the control unit and no flashing lights at all is there?
Ok this isnt a fault with the flood switch as if it was the the display will stay light and the end of cycle will just flash 3 times pause for a secon and flash 3 times again and so on.
So as the display if going blank with nothing lit up and just the pump running then im afraid this is a faulty control board. I have actually replaced a few boards for this fault what its doing.
So im afraid for the fault you have here its looking like the control board is the fault here, Sorry.
Its more then likely a fault on the board thats causing the pump to run.
If your a boiler engineer then ive just uploaded the service manual for this. I know its for the free standing version but its the same as the built in as the controls are just in a different place thats all.
Click the link below to download it and try the test cycle and see what you find. Hopefully this can help you with it
Your very welcome.