Hi, I had the same problem with mine. What you will find is that the base (floor pan) of the m/c has a switch which detects water entering into it. The water sometimes comes when there has been a blockage in the return pipe. If there is water anywhwre in the base then you will need to empty it ( I used a small piece if tube to suck out the water,which saves having to dismantle the base)then let it dry out, you should then find that it will refill as normal. If it fails again in the future then you will need to sort the blockage out.
Tom'llfixit, February 2009