sounds like muck in the hot water system, check the cold water tank in the loft, make sure it is clean.
check the gate valve to the hot water cylinder, after that you need a plumber to fully check the cylinder.
erj
January 2011
hi, have you got a byelaw 30 kit on your coldwater tank in the roof space ? if not water in tank can get contaminated . tank should have lid,insulation all over and vents etc . or could be the hot water cylinder if u have one, the annular inside it can hole and let central heating water into hot water supply. hope this helps .
marti
January 2011
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix plumbing.