Hello. i have recently had boiler trouble, thanks to advice from you guys it turned out to be the thermocouple. trouble is. after about and hour of hot water or heating being on the boiler casing rattles and the flame visible through the pilot window changes shape and colour, this last a matter of seconds then everything goes back to normal. everything seems to be functioning properly, hot water and heating. the hot waster tap had been running just before it happened. do you think the rattling and flame change is a problem. hope someone can help, thanks janine. its a glow worm fuelsaver 50b mk11
