full install - pipe work?

[Deleted member 102951]

Hi all
Im new here... and new to any type of plumbing...
I have a bit of a project - see attached.
Could someone please tell me have I got the pipework ok for this installation?
Am I be better off doing everything in copper or should I use HEP20 everywhere apart from where its chased into walls?
Can I use 15mm piping everywhere or should I use 22mm?
Any advice much appreciated
Thanks
legepe

 

[Allgoode]

Simplistically - Think of the central heating pipework like a tree.

Is the tree trunk the same size as the branches... No, because it has to be bigger to support branches & feed the leaves (rads) .
So feed coming from boiler pipework (trunk) should larger than the branches.
Do all the branches grow from one another... No - They cannot efficiently feed all the leaves that way.
So individual feeds to/fro rads should come off/to supply/return trunks & not be in a loop aka your plan.

Personally i would bring 22mm out onto landing area & individually tap off for each bedroom rad.
For down stairs i would try & drop in 22mm in stud wall void & then 15mm to lounge & bed 1.
Similar for other downstairs rooms.

Other option is the manifold way with 22mm feed to manifold & then 10/15mm feeds individually to each rad. That way if properly done system balancing is easier & with correct set up you can have individual room zones throughout.

A lot to consider but it's up to you.

Also please don't forget to insulate pipes in void areas as well.

Thanks

Andy