"logized" wrote in message
...


The best way is to fit a 3-port "diverter" valve to give a priority
system.
A diverter is similar to a 2-port valve with just another port. The
boiler
will need to be on full temperature. A simple clamp-on pipe stat on the
flow
can be fitted to keep the CH flow temperature down if that is a problem.
Better still, if the cylinder is old replace it with a quick recovery
cylinder to reduce time heating the cylinder. Travis Perkins do the
Telford
Typhoon very reasonably. Doing this will transform the system for little
outlay.

IMM,

I prefer to have valves that allow heating
water and rads simultaneously if
needed,

Why? The reheat takes a few minutes and is more economical. The cylinder
is effectively made larger as all the boilers heat is taken as you draw-off
hot water.

so I would not be happy to use the "diverter" W-Plan option.
Looks like it is going out of favour now also,as I did not see it as an
option from some manufacturers and found an article recommending them to
be
replaced where found see -
http://www.gasman.fsbusiness.co.uk/f...ed_systems.htm

The man who wrote that web site should get to know something about heating
before he starts to write garbage like that.

Thanks for your suggestion on quick recovery cylinder - I want to get one,
but so far only found the "Superduty" by Albion.
And thanks for your recommendation of good valve makes.

Range do one too. http://www.range-cylinders.co.uk The Telford Typhoon is
the cheapest.

A 3-port diverter priority system using a quick recovery cylinder is the
best setup. If using a condensing boiler even better again as the quick
recovery coil ensures a cool return temperature.