NOISY BIASI 24S

pls help! I have a biasi boiler that sounds like an aircraft taking off whenever it comes on.The flame comes on as usual and the boiler starts working.
Then the take off noise(could be described as whining) starts, it gets louder until the noise reaches its peak then everything cuts out
without a bang or any other noise.
i have had an engineer come out to check it, he said there was nothing wrong with the fan or pump but i'm not confident in what he was saying. he added pressure to it (because it is in the loft he said slightly extra pressure was required because it is higher up) this fixed the noise for a day then the noise came back (to a lesser extent though). the noise seems to be coming from the actual boiler and not the pipework although the noise is louder in the house than it is in the loft??? can anyone help

This is less usual on the 24S and more common on the 28S !

Its usually described as a Jumbo Jet but actually is more properly compared with a WWII Spitfire in a powered dive!!!

Its normally caused by severe kettling because the CH power setting has been left at maximum when there are few rads or the rads are mostly turned off by the TRVs.

I am reluctant to give you detailed info as it should be set correctly by a CORGI having first checking the gas valve setup. It could be severely over gassed.

You may be better getting the local Service Agent's number by calling the manufacturers on 0121 506 1340.

Tony Glazier

and yes we turned down the ch setting on the boiler and it went away, we now have other problems see my posting!

The gas valve setup is an engineer function.

The CH maximum power setting is an internal preset adjustment.

Merely turning the user front panel controls will not take the place of a proper setup by an engineer.

Tony