worcester bosch "kettling" noise Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[mick.n]

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.awin1.com/awclick.php?mid=15 ... nvt/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.awin1.com/awclick.php?mid=15 ... nvt/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]

[mick.n]

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

[htg engineer]

Yes it's more likely to be air, as if it was kettling the noise would get louder the hotter the system gets until the burner extinguishes.

It could also be a problem with modulation, it could be staying at high rate for longer than it should, this could just be a sensor fault or a pcb fault.


htg

[mick.n]

Thanks htg. Am hoping it is air. The system seldom looses pressure & maybe once a year i have to top it up to the 1 bar mark, but tell you what, it can be a bugger to get the air out.... & of course the more you bleed the system the more go have to keep topping it up.

Will leave the flush in for the specified time then will drain\flush it a couple of times before putting the inhibitor in. Then see what happens.

Many thanks again for the reply.