"DavidG" wrote in message
...

"Ed Sirett" wrote in message
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On Mon, 04 Apr 2005 12:28:33 +0000, DavidG wrote:

Newbie post from a long time lurker here. Hoping someone can help.

As part of a loft conversion, we replaced the old boiler system.

The old was a 'traditional' open vented boiler system with a pump and a
hot
water tank, a salamander shower pump and a Bensham thermostatically
controlled shower mixer. The new is a Worcester Bosch (WB) 28CDi RSF
combi
in the loft.

Since installation (by a plumber working for the building contractor)
the
heating has been fine, but the 'hot' water has been tepid.
The plumber went through the trouble-shooting routine, said that a flow
sensor was defective and called WB. Today the WB guy came, tested
everything.
He says the sensor is fine but that we had a 'cross'leak'. He thinks
that
the shower mixer is allowing cold water up the hot side and into the
taps
(which he tested by switching off the hot supply and getting a good flow
of
cold water out of the bath hot tap).

The local bathroom place says this is a good quality mixer suitable for
mains pressure and disputes the diagnosis. Any thoughts please - just
trying
to make sure i'm not getting dicked around and looking forward to a hot
shower again.

The diagnosis by WB guy is plausible. Quite a few but not all shower
mixers and bath-shower mixers have this 'feature'. A number of
manufacturers but not all put non-return valves in the inlet to the mixer
to ove come this 'feature'.

The shop may be right in saying what they say about the mixer but that
won't stop the problem in this case.

As a temporary work around try turning the mixer all the way to full hot
or full cold and see if the 'feature' goes away. If you have the sort
that
only have one control that goes from off to cold through hot then you
can't, off course. One or maybe two non-return valves added to the supply
to the mixer will fix it properly.


Well the plumber has been and put a non return valve on the hot side.
We now have good hot water to all outlets but still a tepid shower.
any further thoughts from the jury ?

--

David




What is the make and model of the mixer and is it pressure ballanced?