Hi all,

As part of a house renovation I'm putting in a combi and a thermostatic
shower in the bathroom. Now the shower I've bought (ToolStation £69 job,
forget the make) gives the pressure range as 0.3 to 3bar and I suspect
the water main pressure is higher. Short of getting a different shower
(why people won't list the max pressure of these things) can I just fit
a pressure reducing valve (eg http://www.plumbworld.co.uk/343-4216) on
the incoming main and feed everything including the combi from that?

Also, do reducing valves affect the flow badly? I'm vaguely considering
fitting one at home as I'm about the 2nd house off the main feed and get
a viscious flow rate and ~10bar which makes me eternally wonder that the
plumbing isn't blown apart.

Ta,
Scott

On Thu, 26 Jan 2006 16:13:57 +0000, Scott M wrote:


Hi all,

As part of a house renovation I'm putting in a combi and a thermostatic
shower in the bathroom. Now the shower I've bought (ToolStation £69 job,
forget the make) gives the pressure range as 0.3 to 3bar and I suspect
the water main pressure is higher. Short of getting a different shower
(why people won't list the max pressure of these things) can I just fit
a pressure reducing valve (eg http://www.plumbworld.co.uk/343-4216) on
the incoming main and feed everything including the combi from that?

Also, do reducing valves affect the flow badly? I'm vaguely considering
fitting one at home as I'm about the 2nd house off the main feed and get
a viscious flow rate and ~10bar which makes me eternally wonder that the
plumbing isn't blown apart.

If your incoming main is truly 10bar then a PRV is called for. Almost
everything will be having a hard time (including the boiler which may well
be rated for as little as 8 bar max). Taps will jam and spit and wear out
quickly, cisterns will be whistling as they fill, they will probably need
new washers frequently.
If you truly have 10 bar then I don't think you'll need to worry too much
about the resistance put up by the valve.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

Ed Sirett wrote:

If your incoming main is truly 10bar then a PRV is called for. Almost
everything will be having a hard time (including the boiler which may well
be rated for as little as 8 bar max). Taps will jam and spit and wear out
quickly, cisterns will be whistling as they fill, they will probably need
new washers frequently.
If you truly have 10 bar then I don't think you'll need to worry too much
about the resistance put up by the valve.

It's certainly well over 7bar - the gauge I had only went up that far -
but there was still plenty of scope for going higher (I'd only cracked
the tap open slightly to let it rise slowly.) I replaced the main toilet
cistern with a Fluidmaster valve as it did whistle awfully and it was
lovely and quiet afterwards. Trouble was it filled the cistern in 12sec
flat and, finding the overflow couldn't cope (surprise), I turned down
the ball valve which made a whole new range of noises. A bit of
tweaking made it play an acceptable note but it's not ideal.

The boiler is for a different property but again there's good pressure
and flow so unless there's a good reason otherwise I'll shove one on
there too.

Scott

Also, do reducing valves affect the flow badly? I'm vaguely considering
fitting one at home as I'm about the 2nd house off the main feed and get
a viscious flow rate and ~10bar which makes me eternally wonder that the
plumbing isn't blown apart.

Always fit a PRV for any system with more than 6 bar pressure. Consider one
for between 3 and 6 bar, depending on how the system performs. Don't fit one
below 3 bar.

Also, if you have an unvented cylinder, you must have one to protect that
and there is usually a cold outlet that can provide a pressure balanced cold
supply.

Christian.

Christian McArdle wrote:

Always fit a PRV for any system with more than 6 bar pressure. Consider one
for between 3 and 6 bar, depending on how the system performs. Don't fit one
below 3 bar.

Thanks for that - that sounds like a good rule of thumb.


Also, if you have an unvented cylinder, you must have one to protect that
and there is usually a cold outlet that can provide a pressure balanced cold
supply.

Not got one of those - might go for a heat bank and exchanger at some
point though.

Scott