The machine works OK on 30 and 40 degree progs but on higher temps will fill the drum with water and then won't do anything else. Thought it might be limescale, so have put descaler through the machine and also cleaned out hoses, loads of scale came out but machine still not working. also thought maybe heater wasn't working but have checked manual which says 30 and 40 degree washes use cold water whereas higher temps use both hot and cold feeds so I guess that rules out the heater. Any suggestions.