"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, 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

From the above web site in quotes:

" If you are converting an existing Gravity Hw system to fully pumped then
the new boiler is best located near the cylinder"

Why? This is nonsense!!! he goes on....

"or even in the cylinder cupboard as the Motorised valve is best situated
next to the cylinder"

Why? This is more nonsense!!! The site is full of misguided opinions.