john east wrote:
A year ago we had a worchester Ri boiler fitted on the wall in our
kitchen diner. It's always made a bit of a banging noise. Not every
time, but really quite often; usually just after it turns itself off,
after the boiler being on for a bit.

We have just had our first annual service. The chap never even opened
the boiler, but just fed a meter tube into the top of it and he also
watched how fast the gas was going out of the gas meter.

I asked him about the banging. He asked if the rads had been bled
recently and I confirmed that they had. Since it was suggested to me
that this might be a cause of all the rucus. After looking in the
water cylinder cupboard he told me I needed a 'by pass' or a 'mixer
valve', but looking at it he wasn't sure where the by pass pipes
would be connected.
Are these 'by pass' and 'mixer valve' not items that should have been
put in when the boiler system was installed last year?

Is it an S Plan by any chance?

http://wiki.diyfaq.org.uk/index.php?title=Central_Heating_Controls_and_Zonin g#CH_and_DHW_zones:_S-plan



--
Adam