I fitted a replacement new fan (bought from "Keeptheheaton.com") to my Glow-worm Ultimate 70FF gas boiler last week (bearings were noisy on the old fan). I now find there is a lot of vibration through the boiler assembly and pipework which can be heard and felt in the adjacent kitchen. It is OK at first when starting up from cold, but when the boiler is up to running temperature the vibration is very evident. Maybe this is typical of replacement fans, the original items being superior in quality to any maintenance item (like a lot of domestic repair spares), but at a cost of over =A3100 it seems alot to pay for something which is not really very satisfactory.