worcester bosch kettling noise

Had a complete heating system installed in september 1998 consisting of 6 radiators (Previously solid fuel)

The boiler is a worcester bosch 24i that has not had any major problems, apart from a leaking auto vent valve & air pressure switch faulty (Both of which were replaced).

Last few months there is a noise from the boiler that occurs when the heating comes on, but not right away, only when the system starts to get warmed up (after about 5 to 10 minutes of running).

After a few minutes this noise stops & doesnt reoccur untill the system is cooled down, then the same thing happens again.

I noticed that if i turn the roomstat down ( enough to cut the gas supply) the noise stops immediately.

Thinking it may be an obstruction\sludge in the heat exchanger, i put some of this cleaner in to the system via a radiator

http://www.wickes.co.uk/Easy-Squeeze-Cleanser-Concentrate/invt/159831

It states that it should be left in for around 28 days. I also bought some of this protector to put in after i flush out the cleaner.

http://www.wickes.co.uk/Easy-Squeeze-Protector-Concentrate/invt/159830.

If it is kettling because of scale build up, would it not make this noise all the time the heating is on & not just at a certain point in the heating process?

Thank you.[/url]

Would air trapped in the ch circuit cause this type of noise?

Kettling on a modulating boiler is most noticeable when it first comes on at full power.

There are so many things that can go wrong with a boiler which has not been PROPERLY serviced by a gas engineer!

Without hearing the noise I cannot say what it is in your case. Unlike some others I dont just list possible causes.

Tony