House water feeds through manifolds

[Sunil237]

Hi all,

 

I saw some really nice ideas on using manifolds from the cold feed and from the dhw to distribute through the house. I have a few specific questions related to my plan I hope you all can help guide me on.

 

My project is a full house refurb and extension. I'll have 3 bathrooms, 1 kitchen, 1 washing machine connection (at the back of a bathroom), and hot and cold to taps outside. 

 

My current thought is to do this;

Hep20 fittings and pipes

New 25mm MDPE to plant room > 22mm stop cock > water meter > 4x (each bathroom & to cylinders) 22mm manifold ports + 2x (kitchen & outside) 15mm manifold ports > at each location secondary manifold to feed each appliance/fitting with 15mm 

 

The above would then be repeated to supply hot water but 1 less 22mm manifold ports as I can exclude the cylinder.

 

Questions;

1) is it ok to go from a manifold to another?

2) should I use 15 or 22mm to go from the manifold to the secondary manifold?

3) Should I use 10 or 15mm to go from secondary manifold to appliance/fitting?

4) Is there a better brand to use for this type of system? I am using hep20.

4) does the order of the manifold matter?

5) any other tips?

6) is the general layout of my idea ok? Any suggestions?

 

I really hope I haven't misunderstood all this manifold stuff! 

Thanks in advance 

Edited December 7 by Sunil237

[JohnMo]

A sketch of your proposal would make it clearer what you propose. An idea of distance also would be good.

[Nickfromwales]

It’s pointless going manifold to manifold, as that defeats the whole object imo. Having higher volumes of ‘dead legs’, before basin taps in particular, means that you’ll waste a lot of water/energy getting premium temp (hot) water out of high-frequency/low volume outlets (if there’s no hot return circuit).

Not a concern for baths and shower, less of a concern for kitchen/utility taps, but defo a sticking point with basins where you just want to flick the tap on and wash your hands.

Stick with Hepworth, it’s all I use these days and is simply bombproof. Where failures occur is when someone installs the pipework and scratches the outside diameter linearly causing leaks/weeping joints. If there’s a few turns and twists the simply install offcuts of 25mm flexible conduit at these points and draw the pipe through them; particularly helpful if doing this on your own (single handed). These can stay in to allow some movement if necessary, and this should be considered for longer hot runs where the pipe will expand/contract a little with temp changes.

Without distances from the cylinder to the outlets, and what they do, it’s impossible to advise on pipe size

36 minutes ago, JohnMo said:

A sketch of your proposal would make it clearer what you propose. An idea of distance also would be good.

what he said   

[Sunil237]

Sorry for the delayed response, ill kids

thanks @JohnMo & @Nickfromwales

 

Here are some sketches. I do not have a proper floor plan for first floor unfortunately.

I plan to feed my new cold water main (green square) into the plant room which is located at the centre of the ground floor, my house will be 10m wide x 11m deep on ground floor, and 10m wide x 6m deep on 1st floor. There is no plan to put in a hot circuit.

 

The plant room will also house my hot water cylinder, the purple square.

 

The approx run lengths, including verticals, to these rooms are as follows;

 

1. Kitchen: 12m
   • Kitchen sink, dishwasher, fridge, outdoor taps (h&c)
2. Outside rear wall: 12m
   • outdoor taps (h&c), shower, future hottub.
3. Downstairs WC: 8m
   • Basin tap, toilet, future shower
4. Utility room: 8m
   • Washing machine directly behind WC.
5. Family bathroom: 8m
   • Basin tap, toilet, bath, shower
6. En-suite: 8m
   • Basin tap, toilet, shower

Happy to consider individual pipes if a secondary manifold method is the wrong way to go. But it then takes me to 28 feeds + 1 for cylinder all within the plant room and approx 300m of pipe.

[JohnMo]

I would just keep it simple 

 

One hot and one cold manifold in plant room. Then one of the two options below.

 

Option 1. Looks like a 5 port manifold for hot and cold. A single 15mm feed from manifold to each wet room, in hot and cold.  From 15mm pipe in wet rooms, teeing off to users - sink, toilet, shower etc. (this what I did and have seen no issues.

 

2.  Bigger manifold in plant room, with individual (suitable sized pipes) to each user in the house. So a mix of 10 and 15mm.

[torre]

We did the same as @JohnMo 's option 1. All run in 15mm Hep2o so no joints at all from a manifold (with isolation) all the way to each room (so each room is easily isolated and can be worked on separately). There you can just tee off as needed or use a secondary manifold (with or without isolation) if that works better (Hep2o manifolds are just a block of tees at the end of the day). For some rooms we reduced down to 10mm for basins just to make the runs easier to work with.

[Sunil237]

Thanks John and torre

 

For option 1, is there any con in using 22mm from the manifold to the wet rooms?

I have a decent length of hep 22mm piping that I would like to use up 

 

For option 2, if I'm able to this I could only do it with plastic manifold fittings due to the cost. Any disadvantages compared to the brass manifold?

Any suggestions on manifolds? I only see a few options here but a few different systems in US 

 

Thanks

[Nickfromwales]

25 minutes ago, Sunil237 said:

Thanks John and torre

 

For option 1, is there any con in using 22mm from the manifold to the wet rooms?

I have a decent length of hep 22mm piping that I would like to use up 

 

For option 2, if I'm able to this I could only do it with plastic manifold fittings due to the cost. Any disadvantages compared to the brass manifold?

Any suggestions on manifolds? I only see a few options here but a few different systems in US 

 

Thanks

Use the 22mm up on the cold runs first, hot runs last, but preferably use 15mm for the hot feeds wherever possible (10mm where it's a basin and close (less than 10m) to the cylinder).

 

Decide if you want / need to be able to isolate every single run, and if not you can go with the plastic dumb manifolds to save a lot of £'s.