Manifolds from PSW...

[RichJ]

Hi

 

I'm at the design stage for replumbing my first house. There's loads of cast iron, lead, imperial copper of all different sizes all over the place and the hot water performs so badly, I'm up for starting again with everything except the boiler.

 

The house has a full length dry-ish cellar and also a converted attic so there's 4 floors. I've found places to locate manifolds in a fairly central location on each floor so I'm thinking a manifold system for both the DHW and heating would work well.

 

I have a Viessmann 100 combi boiler is in one corner of the cellar approx 1 metre away from the bottom of a false wall. This false wall (approx 2.75m high) goes up through the kitchen eventually hitting the bottom of the airing cupboard. I'm thinking of taking copper from the boiler to the top of this false wall (as single 3m lengths i.e. no joints hidden) then converting to Hep2o or Pex in the bottom of the airing cupboard. So there will be joints in the bottom of the airing cupboard but nowhere else other than at the manifolds or the rads etc. The reason for this is occasionally we get random animals in the cellar / attic (shrews etc.) so I'll risk plastic in the main part of the house just not the cellar or the attic.

 

I was wondering if anyone could help me with some things I'm not sure on? Sorry they're so basic, I haven't seen anyone else on here asking about these kind of things.

 

1, I've been looking at the manifolds from PSW trade supplies for the heating. Is there any difference functionally between a plated-brass manifold and a stainless one or is just cosmetic?

 

2, The inlets on the PSW manifolds seem to be 3/4", can I use Pex-Al-Pex for this or does it need to be 22mm copper? If I can use Pex-Al-Pex what size pipe would I need? I guess it would need to be 25mm maybe?

 

3, The install instructions on the PSW manifolds say that have to be installed vertically. What would happen if I lay them flat?

 

4, Most of the pipes PSW sell seem to be Pert-Al-Pert rather than Pex-Al-Pex. I get the feeling that wasn't the case in the past as a lot of the posts on here mentioning PSW refer to Pex-Al-Pex. If I'm going to be using a combi with a flow temp of 50-60 degrees, is there any disadvantage to me using Pert-Al-Pert rather than Pex-Al-Pex?

 

Thanks so much for any help!

Edited December 2, 2023 by RichJ

[Conor]

These sound more like central heating manifolds? I used these. 22mm copper straight in one end, 15mm PERT out. Can't be faulted. Apart from the fiddly demounting tools. Also come in 10mm for runs to wash basins or WCs.

[JohnMo]

Heating manifolds are not the same as those suitable for DHW hot and cold. Get the right one for the right service.

 

Pert-al-Pert, doesn't have a memory so easier to run from point to point. Straighten and it stays straight.

 

Follow your boiler installer instructions on piping materials and if you can use plastic close to the boiler.

[RichJ]

Hi Thanks for your replies.

 

Sorry I cut some pretty important detail out from my original post just because it was long enough already. I can see it reads like I was suggesting connecting the boiler up to pex. That's not my intention at all.

 

For DHW I'll be using Wavin/Hep2o barrier pipe and their manifolds. For heating I'll be using UFH manifolds such as the ones from PSW with a mix of copper / pex-al-pex pipe.

 

In all cases the pipework within about 2 metres of the boiler will be copper / end feed.

Edited December 2, 2023 by RichJ