Phil L
wibbled on Sunday 06 December 2009 22:27

Vortex5 wrote:
"Phil L" wrote in message
m...
Vortex5 wrote:

Why on earth would they say that? It won't make any difference to
the static pressure.


So even when the tap's just trickling, the water's at 10 bar?

what if it's turned down so low that it's just a slow drip when fully
open, is it still at 10 bar then?


When the internal tap is off, yes.

Yes but it wouldn't stay at that pressure for more than a second or two
when using a tap, so filling a kettle, as you mentioned in your OP,
wouldn't be 'alarming'


I beg to differ...

That's not a reliable method of regulating dynamic pressure, which will now
be all over the place depending on demand.

It also doesn't help any equipment that doesn't like such high pressures as
they will be seeing the static pressure regularly. It would also be a
potential disaster if the OP had mains pressure DHW and plastic.

Looking at an offcut of JG Speedfit pipe, I see the pressure ratings a

12bar at 20C
4 bar at 82C
3 bar at 92C

The figure for 60C isn't given but I can't see JG pipe enjoying 10bar at
much over 40C if that.

IME, certain garden hoses (hello Screwfix) fail early at 7.5bar, so for
anyone with 10bar static pressure, I would rate it as a *very good* idea to
include a pressure regulator next to the stopcock. I found 7.5 bar a big
enough pain to include a regulator in my system. No real disadvantages and a
decent device does not reduce the flow (I tested this specifically). CAme in
very handy when I wanted to install a water heater that required 6bar (the
included pressure relief valve is set to 6bar).

Cheers

Tim

--
Tim Watts

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