Thanks for the comments.

I have spoken to the friend again and apparently they've already been in
touch with the gas people who installed the central heating etc and (I
assume it was after a visit) they said it's nothing to do with them and
suggest that they chase up the people who subsequently fitted a new
bathroom suite in.

I don't know if those people are the same as the one that fitted a new
ball cock in an effort to stop it.

I hope to be going round there on Saturday, so will try and get more
information/check things out then.

Roger



In article , ()
wrote:

A friend has a problem with water hammer, that she showed me today.
It's the usual one-off "thump" when the tap is turned off.

The arrangement seems to be that there is no hot tank, the hot water
being supplied on demand (and presumably at mains pressure) from a
combi boiler. The system was installed as part of the central heating
system about a year ago. There is an upstairs header tank in the loft
which I assume feeds the cold supply to the bath, wash basin and
toilet. I suspect there used to be a water tank with immersion heater
before the new system was installed.

The water hammer occurs every time that the hot tap is turned off -
bath, wash basin or downstairs sink. It doesn't occur at anytime the
cold water is used. I don't think that it occurs when the cold tap is
used in the kitchen. The kitchen taps go through a mixer and this is
hard to turn off suddenly in one go. The bath and wash basin taps are
mixer taps with a single lever that has a left/right movement for
mixing and an up/down movement to turn the water on/off. This can cause
the water to stop immediately.

Although this only seems to occur from the hot taps, I assume that it
also occurs on the cold water main taps (I forgot to ask if it happened
with the washing machine.

She called in a plumber who replaced the ball valve in the header tank,
but that made no difference (I'm not sure why that was changed, given
that the it happens from other sources, but I assume that the plumber
knew what he was doing.

Any suggestions as to what could be done?

Thanks

Roger
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