Central heating pipe size.

[steve.c]

I am in process of changing radiators and water pipework for a new heating system. The only thing that will be changing is the boiler location (Back boiler to combi in airing cupboard). I am planning on running the pipework along the lines of the existing pipework but notice that three of the smaller radiators have been piped in 10mm. Are there any pros-cons to using 10mm or is 15mm better. Thanks

 

[Bahco]

You should aim to feed each rad off 22mm pipe for ease of flow although I have seen 3 rads being fed from a 15 mm branch.

Best practice is 22mm.

 

[steve.c]

Thanks Bahco I have just edited original post. I didnt expect a reply so quickly. The combis I have been looking at have 22mm water connections not 15mm as I wrongly stated.