I've just put in a regular bath tap mixer shower into my new bathroom
(i didn't have the time to put a thermostatic mixer in just yet - it'll
have to wait a little while yet i think). The shower actually works
fine - certainly better than the Mira electric shower that was at the
flat I've just moved out of.

I've just had a heating engineer come and look at my Vokera Excell 80SP
combi boiler as I'm not getting a great flow rate of hot water - only 5
or 6 l/min. He reckons this is mainly due to the limitations of the
boiler which is probably a fair comment.

However, on seeing that it was a bath tap mixer he then started
mumbling things about it not meeting water regs. As far as I'm aware
the only thing I have to make sure of is that there's a hook thingy to
stop the shower head going below 4" above the plug hole.

Is there anything else I need to do to meet water regs before I finish
this bathroom off and move on to the next job she wants doing?

Thanks,
Dan

Is there anything else I need to do to meet water regs before I finish
this bathroom off and move on to the next job she wants doing?

Either the mixer tap itself (by dint of its design) must prevent the
possibility of hot water going back up the cold pipe and backfeeding
the supply, or a double-check valve should be fitted further upstream
in the cold supply to make sure hot water can't flow back up the cold
pipe.

(In theory this unlikely situation could occur if the hot supply
remains under pressure and the cold pipe develops a vacuum. There is
then the possibility that the public main could be contaminated with
your dodgy water causing widespread public poisoning. Not really a very
likely problem with mixer taps but more important on say a outside tap
where a hosepipe dangles into a garden pond which could result in
frogspawn etc being sucked up into the water main... not too clever.)

Wingedcat wrote:
Is there anything else I need to do to meet water regs before I finish
this bathroom off and move on to the next job she wants doing?

Either the mixer tap itself (by dint of its design) must prevent the
possibility of hot water going back up the cold pipe and backfeeding
the supply, or a double-check valve should be fitted further upstream
in the cold supply to make sure hot water can't flow back up the cold
pipe.

(In theory this unlikely situation could occur if the hot supply
remains under pressure and the cold pipe develops a vacuum. There is
then the possibility that the public main could be contaminated with
your dodgy water causing widespread public poisoning. Not really a very
likely problem with mixer taps but more important on say a outside tap
where a hosepipe dangles into a garden pond which could result in
frogspawn etc being sucked up into the water main... not too clever.)

One additional detail: The mains pressure going low (not a real
vacuum, but anyway) can happen in real life - it's not just
theoretical. If the Fire Service turn up and start pumping water out
of the mains ...

On 5 May 2006 03:34:16 -0700 someone who may be "Wingedcat"
wrote this:-

(In theory this unlikely situation could occur if the hot supply
remains under pressure and the cold pipe develops a vacuum.

Not very likely if hot and cold are fed from the same supply, as in
a house with mains pressure hot and cold water.

There is
then the possibility that the public main could be contaminated with
your dodgy water causing widespread public poisoning. Not really a very
likely problem with mixer taps

Provided that the shower attachment is restrained so that it cannot
be submerged in bath water which could be sucked back into the
mains.

but more important on say a outside tap
where a hosepipe dangles into a garden pond which could result in
frogspawn etc being sucked up into the water main... not too clever.)

IIRC the concern about this was prompted by a farmer who had a hose
pipe immersed in a large tank of weedkiller when the mains pressure
reduced and the weedkiller back-siphoned into the mains.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54