On Thu, 04 Nov 2004 17:34:20 +0000, IMM wrote:


"Tim" wrote in message
news
On Thu, 04 Nov 2004 16:36:36 +0000, IMM wrote:

A 4-port proportioanlly reduces one loop in favour of another. If
mid way 50-50 to each. If open 25% then 25% to one and 75% to the
other.

Hi

Yes - I understand that bit - just wondered in what situations a 4 port
would be called for, rather than a 3 port?

Look at:
http://www.leemick.co.uk/ufh/tech/36345.htm

If the 4-port is half open 50% of the boilers flow through the UFH
circuit and 50% back to the boiler. If it 100% one way it goes all into
the UFH. 100% the other way 100% back top the boiler by-passing the UFH.
The boiler return always has the same volume of flow back to it.



Doh! slaps self Yes - that would be an irrelevant consideration in my
setup,so I didn't think of it - but I could see that it would matter in
certain types of installation.

Ta.

Timbo