Thanks Bill, I'm coming to the same conclusion as the lack of reliability of
the 3 port valves seems to be a widespread opinion.

Eric
"BillR" wrote in message
...
EMC wrote:
I am just about to embark on upgrading my old oil fired gravity hot
water / pumped central heating system to a gas fired fully pumped
system and am unsure what arrangement of valves to use. What are the
advantages / disadvantages of using a 3 port valve instead of two 2
port valves to control a fully pumped hot water and (single zone )
central heating system?

I'd recommend two 2 port valves. The normal 3 way ones are a pain in my
opinion.
They are always breaking down and its also difficult to tell what mode
they've failed in.
My current (3rd) one won't shut off the CH properly. I'm changing it for
two
2 ports as soon as I can get round to it.