From: "Tim"
Subject: Underfloor wet heating - alternative to mixer?
Date: 04 November 2004 15:15

On Thu, 04 Nov 2004 14:47:30 +0000, IMM wrote:

No need for a 4 port mixer. A normal cheap 3-port will do.

What's the practical difference between 3 and 4 port? I know roughly what
they look like, so I presume the 3 port just short circuits the pipework
under the floor when less heat is needed?

Would you use a 4 port if you needed more than one circuit off it?

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.

The simplest systems are from the likes of Polyplumb. Go to their web site.
their equipment is expensive, but you can buy the component parts and do it
yourself.