WHISTLING NOISE FROM COMBI?

[novascotia]

Over the past couple of days my combi boiler has started to make a "whistling noise".
When i say the combi you cant here anything in the airing cupboard its in. The only place you can here anything is in the bathroom. There is a flue extension that runs through the bathroom to the outside wall. Im thinking its just the noise of the air going through the flue, but me and the wife have never noticed it before.
Does anyone have anyother ideas. It is a fan flued worcester bosch 240 if that makes it any easier
If the flue/boiler has been off for a while then comes on it doesnt make teh "whistling" noise for a while . is it possible there could be a blockage or something in the flue causing this noise
or could the fan bearings be on there way/need lubricating, listen at me as though i know what im talking about
does anyone have any other ideas please????
many thanks

 

[ChrisR]

No obvious suspect but it could be a number of things on your boiler which is a "certain age" now. You need a corgi to go in there.

 

[novascotia]

cheers chris
everything appears to be workin fine with the boiler no pressure loss (anymore) fires up a treat. and no noise from the combi itself . it can only be heard in the bathroom passing through the flue pipe. and its only when the boiler has been fired up for an hour or so. when cold just normal noise if you know what i mean