"PeterC" wrote in message
...
On Sun, 06 Dec 2009 22:45:08 +0000, Tim W wrote:

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.

Much the same for washing machine hoses, but lower pressures. In the rare
case of a machine that uses hot fill from a combi,

Rare??????

the hose will be full of
hot water when the filling ceases and mains pressure on a hot hose...!

A few years ago I installed a Miele and that hose was much higher rated
than standard ones.

With these sorts of pressures, it is best to have cold fill only. Most
washing machines are these days. Cold 30C washing liquid is very good. The
have a 1/4 turn tap under the sink at the front so the machine is turned off
after each wash, or have a remote operated water tap, available from S/fix
and the likes. Just hit he switch and the cold is off.