On 16 Jan 2004 10:32:20 -0800, (simon_london) wrote:

I want to buy a new Glow Worm 24cxi condensing combi. To keep costs
down, I want to get all the pipework ready before a CORGI plumber
commissions the boiler. The manufacturer states that the central
heating pipe and return pipe should be 22mm. All the pipework on my
existing central heating system is 15mm. I read on several internet
articles that to ease the load on the pump, the central heating loop
should be fitted with 22mm pipes, and each radiator should be
connected to the main loop with 15mm pipes. I will have 9 radiators in
total (about 42,000 BTU's output).

Does anyone know the pro's and cons of fitting 22mm pipes for the main
heating loop rather than keeping the existing 15mm pipes?

Another thing you might want to look at is whether the syetem is plumbed in such a way that you can
split it into 2 sections and just run 22 to the point where they seperate. This might be a good
compramise between increasing flow and hassle of re-plumbing.