"John Stumbles" wrote in message
news
On Sun, 19 Mar 2006 17:08:36 +0000, Roger Mills wrote:

Make sure you use barrier pipe - some makes, such as Hep2o come in 2
versions, only one of which is suitable for CH systems.

.... unless you have inhibitor in your system. The amount of air absorbed
through non-barrier pipe is probably still vastly smaller than from the
header tank in an open vented system.

British Gas will not take on a system with non-barrier pipe.