Baxi / main boiler making creepy noises on central heating

[baby_belling]

I have had this Main 30 eco combi boiler for over a year now and its has always been reliable, untill recently when I have been using the radiators more often, I noticed this strange noise like a flute or squeaky brakes on a lorry being amplified through the pipes/radiators.

At first i though it was outside so did not take much notice but now it is happening more often and now sounds metalic, like a microphone being tested. It is louder in the bedroom next to the boiler and in the bathroom where the boiler is located.

It only happens occasionally but is enough to wake the neighbours. I have noticed that it happens mainly when the boiler fan slows down but is fine when the heating is at a steady speed. It is louder the radiators than the at the boiler itself.
I have checked all the trvs and all are quiet and tried turning off and on the radiators / bleeding but no difference. yet the boiler works fine and no error codes etc Any ideas as it did not do this before,

 

[mcmoby69]

have you had it serviced since it was fitted?

 

[baby_belling]

it is getting serviced next week as it is just gone one year old but I can bet the noise wont be there when the plumber checks it! its kind of intermittant, I have tried turning the boiler thermostat down but no difference, any clues as to what it could be, do you think sentinel silencer would stop the noise vibrating through the pipes?

 

[mcmoby69]

could be anything, gas valve would be one of the first things i would look at tbh. your service guy should be made aware of this problem.

 

[baby_belling]

I know it has been quite a while but the installer has come back and said straight away that the fan needs replacing as the bearings are shot, As soon as he took the cover off you could hear a loud vibrating noise which I always thought was the norm for this boiler it did this from day one, I buit a special cupboard to hide the noise! luckily it has 2 years guarentee, hopefully when baxi come out i will have a nice quiet boiler!!