Can you guys help me out with a shopping list for first fix?

[cjard]

The soil and waste are sorted (not so many options there) so it's just the potable side. The incoming supply pipe is 32mm. What reduces that to a sensible diameter to start running pipe work? Most of the piping will be hidden and Im not averse to using plastic e.g. Speedfit. Do I need to buy my appliances (baths, showers etc) first to know the connectors or is it fairly well guaranteed that the fittings for any given bar thermostatic shower (for example) will be the same diameter and distance apart?

The other thing, and tel me if it's daft, but I have stacks of 16mm pe pipe (WRAS blah blah) left over from the UFH, and I note it's possible to get reducing couplers to go down to normal 1/2 and 3/4 fittings and 15mm compression ones too, so is it a really daft idea to plumb the house using this 16mm (bath excepted maybe) that reduces to 15 or terminates in a suitable 1/2 or 3/4 when it reaches an appliance? What to do for a manifold you ask? Well, I could buy a UFH manifold without pump if the flow rate could be dialled up enough...

i did catch reference to a thread here where a guy was DIY his plumbing and he mentioned pipe that is fitted inside conduit so catching a leak and running a new pipe was apparently easy. Is this common? Wise? Relatively cheap?
Another q, do speedfit do manifolds so you can get away without joints? I deliberately designed the house so all water consuming appliances are near each other so running a pipe from the utility to each isn't an arduous task..

 

[dilalio]

Wow... That's a big ask!

I would offer up...

Where you can run hep in a continuous run, without joints, through walls and floors, then use it!

When you need to put in elbows, tees etc, and it's concealed, soon to be inaccessible, use copper and sweated joints. Pulled bends where you can.

Clip everything and put in noggins where required and put clips on to those. Anything to prevent pipes knocking under changes in pressure when water is drawn through.

Insulate pipes with foam under ground floor and in attic, garage etc.

If you have a HWS cylinder, consider incorporating a secondary return on the DHW to circulate hot water so never far from hot draw offs.

Have all sanitary ware, appliances on site or technical data to hand to ensure pipe centres, sizes and heights above finished floor will be positioned correctly... There are many differences between manufacturers and models.

Sleeve pipework through solid walls. Especially gas which your RGI will be doing!

Change any plastic pipework to copper where it exits walls, floors,
Unless hidden behind units etc.
Pipe radiator tails to exit walls rather than floors... Looks much better, aim to have base of rads sitting 1" above skirting.

Up to you if you use the PE but it's less flexible than normal hep on a roll and will always require non standard fittings to tap into for any future modifications!

My tuppence worth

 

[cjard]

dilalio, cheers for that

What reducer do I need for the 32mm supply, and what will it reduce to (as a first stage) to get into the "normal plumbing" diameters?
I see these:
http://www.screwfix.com/p/floplast-mdpe-male-adaptor-32mm-x/6799f
http://www.screwfix.com/p/floplast-mdpe-female-adaptor-32mm-x-1/5427f
http://www.screwfix.com/p/floplast-mdpe-male-adaptor-32mm-x-1/4508f
http://www.screwfix.com/p/floplast-mdpe-female-adaptor-32mm-x/3708f
And I also see things like these:
http://www.mrcentralheating.co.uk/mdpe-coupling-32mm-x-22mm-conversion-reducer


regards running hep/similar in continuous runs - yep, i'm game for that.. I just have a query as to how to manifold the supply end - I see these for example:
http://www.plumbcenter.co.uk/en/plu...-speedfit-4-port-rail-manifold-22-mm-x-15-mm/

but they seem to be more for rads than fresh water uses; can they be used for potable? do bigger versions exist e.g. 10 way ones or does one have to daisy chain these things together and blank off unused ports?

Or, I see these:
http://www.combicentre.com/products...Port-Single-Sided-Manifold-(Socket{47}Spigot)
Is it intended that to increase the number of ports one would cut the end off the manifold and plug it into another manifold as many times as necessary?

 

[dilalio]

The size of your internal carcassing (pipework) depends on many factors...
• Incoming pressure
• Dynamic flow
• Length of runs to different water consuming services
• Height of certain installations
• Boiler, CH & DHW setup and demands
• Number & layout of rads
• Heating zones (towel rail circuit, UFH etc).
• Valve demands (showers, bath fillers etc)

With a megaflo type system we normally run inch where able (especially to the master bathroom) then step down to 22 to any other "baths" then 15 to wc's and ensuites etc.
With heating we 22 a flow & return to each terminus and T off of that at rad positions in 15 -occasionally 2 rads on one 15mm pair if we have to!

We don't use manifolds (except for testing pipework) in the "star" type distribution as you seem to be thinking. You should carcass in 28>22>15 according to demands at each outlet!

 

[Biggles..]

With a 32mm PE main, inch pipe is pointless.
22mm to cylinder, 22mm hot and cold out splitting to 15mm for bath/shower, 10mm for basin and bogs.
Remember water useage and wastage figures now make big internal carcassing pointless.

Rad circuits normally in 15mm with 10mm to each rad.

Things have changed over the last 10years.
22mm/15mm heating circuits are required less and less.

You're getting well over 10kw out of 15mm on a modern condensing boiler aiming at a 20deg delta.

If you have a cupboard etc central then manifolds hot and colds is the way forward.

 

[cjard]

It was a conscious decision to design the house so that the utility is at the centre, WC downstairs adjacent, and master bath and guest ensuite immediately above, kitchen wet wall backing onto utility, so that all the pipe runs were minimised. Looking at going for a manifolded system, because I don't want a branch setup where I have to turn a tap on and wait 2 minutes for it to come hot as a smaller pipe empties a large amount of standing water out of the main feed.. i know its minimal with short runs, but still.. It's a waste, and a cost

So, 22mm to bath (immediately above the tank/thermal store), 15 to showers and 10mm to taps and also 10mm to toilets, washers, dishwashers etc? Or because those devices are cold only, really, I can just run 15 because it's not a standing water problem

I'm not really bothered about water flow rates to taps, and slower is probably better being on a meter.. As noted, most tap pipe runs should be a few metres only

Heating is UFH so manifold setup already

 

[dilalio]

It was a conscious decision to design the house so that the utility is at the centre, WC downstairs adjacent, and master bath and guest ensuite immediately above, kitchen wet wall backing onto utility

Ok. Didn't realise you'd gone to that extent. Is it a new build or gut-out and remodel? We do a lot of large remodels and you are often stuck with old layout as well as new, hence I mentioned house layout as an important factor. You don't seem to be faced with this

I don't want a branch setup where I have to turn a tap on and wait 2 minutes for it to come hot

This is why we incorporate a secondary return into the DHW system... Solves the HW response time!

As you have designed the house and probably have a services conduit built in, then yes... manifold system into utility "hub" would seem practical and if you can do all the runs, joint free: even better! Just ensure you label all those 'strands' as you pipe back to the utility & secure them well

And this might be useful to you...
http://www.jhplumb.com/system/brand...ginal/Hep20_Technical_handbook.pdf?1279698363

 

[cjard]

I thought about secondary return but I don't think it will be necessary for the run lengths I have- longest pipe is probably 10m. Saves on running a pump too, and I'd have a concern that it would route through a part of the house seldom used and thus a parasitic heat loss to an area where the heat isn't appreciated often; better to keep all that heat in a large vessel with low s/a:volume ratio and covered in kingspan, than a lagged pipe which is pretty much the opposite!

This is a new build so no awkward layout issues..

 

[dilalio]

Yep... And those bronze pumps are not cheap!