Central heating pipes

[Mandy]

I am about to install a combi central heating system. Having chosen the boiler and radiators, I'm at a loss to work out what type and size of pipwork to use. Can anybody tell me if plastic(Hep) pipe is man enough for the job?
Also, do my main circiut pipes have to be 22mm throughout with short 15mm runs just to the radiators or can I use 15mm for most of the system?

Mandy.

 

[AnonymousImport]

i suggest you get a book from the library on central heating.

 

[AnonymousImport]

In very general terms - plastic pipe is OK for central heating - along as it is a 'barrier' type pipe. Some others are gas-permeable and can contribute to corrosion in the heating system. However, you are not allowed to use it within 2m of the boiler, so use a bit of 22mm copper, and then transition it to plastic away from the boiler.

Most domestic heatings systems should be OK using 22 mm primaries - flow and return from the boiler to the heating manifold. You can branch from here to each radiator in 15 mm, unless the pipe runs are very long.

Consider also what controls you will be using - do you want multiple zones with independent time control - e.g. a bedroom zone timed seperately to the main living area zone. If so, you will need to make provision for motorised valves when designing your pipe runs.