I have a Worcester 28Cdi Combi boiler fitted by British gas approx 2
years ago, and is still under a service contract.
In the last 3 months there has been a vibrating from with in the casing
of the Combi. This usually occurs after any water in the house has been
used (hot or cold). The vibrating is Intermittent. The vibrating will
last 3-4 minutes and will then stop, but it can be stopped immediately
by opening up any tap in the house (hot or cold)
British Gas have been in twice, but have been unable to fix the problem.
Recently they adjusted the water pressure on the Combi from 1 to 1.5.
The engineer then left as told me to log a new call if the problem re
I don’t want to fix the problem my self, just some ideas of what could
be causing the problem so I can pass them on to British gas.
Just before the problems started the ball valve was changed in the main
tank. Could this have anything to do with the vibrating, or it just a
Sounds like a 'water hammer' problem: not necessarily a fault in the boiler
but maybe an interaction between the new float valve, something in the
boiler, and the configuration of the pipework in your house. You could try
(a) tying up the float valve and/or (b) partly closing the incoming mains
stopcock, and seeing if it affects the vibration: this would tend to confirm
the water hammer theory.
If it is water hammer then you could alleviate or eliminate it by
introducing a length of plastic pipework into the feed to the tank in the
attic. (There are also custom surge arrestor devices you could plumb in, at
a price, or another diy approach is to have a short stub of pipework
continuing vertically from near the float valve, going nowhere but trapping
a bit of air to reduce the hammer.)
I've got a book about motivation but I've never got round to reading it
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