I have an Hotpoint Ultima WF840. It also had F-05 on it. We took off the back panel and disconnected the hose (plastic clip was a pain but came off after about 10 mins of waggling it). Took out the pump, cleared it and some debris was in pump and filter under drum (including toe end of a pair of tights, a bra wire in pieces, the fastening section off a bra and some curtain hooks, only gutted there was no money ha ha). Turned the blades inside pump which still clicked but put together again and set away. Drained ok this time but still made buzzing and clicking sounds.
So we had to replace the pump (we were lucky, next door's hotpoint had busted electrics and they'd bought new rather than fix so we used their pump as was in perfect working order, but they are cheap enough from an independant retailer and very easy to replace).
Its now all working perfectly, and just as silent as it was on first purchase.
After all the panics about paying for repair or taking apart, it was very eays and all my washing done again.
Hope this helps anyone who needs it!
Suzie, December 2007
