JanetE

Hep 20 Manifold

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Just about to start on the Hep 20 plumbing in 15mm and we are having a manifold system. 

I was wondering how to make up the actual manifold as they do not manufacture one, unlike Speedfit. 

We have 12 connections on the hot supply and 17 on the cold. I would be interested to know how all you experts go about this?

Thanks in advance for your help. :)

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image.jpeg

 

This is the best 'zoom-able' pic I can find. 

The rails are supported by the pipe work which is held in place with brass Munson rings. Copper to irons on each end, and as a belt n braces job I created a ring so the manifolds got fed from both ends. I did that as the cold manifold was very long and could have suffered loss of flow and I just then carried that across to the hot manifold to as it was easy enough to do. 

The remit on that job was to be able to use all the showers at the same time and still have some useable flow / pressure elsewhere so went to town on this one. 

If you zoom in you'll see opaque / white plastic spacers in between the manifolds ( 3 to the long run ). These iirc were 28mm Talon pipe clips which held the rails with near spot on results. Another way to do this, if only feeding from just one end, would be a clip on the input pipe work and then a stub of pipe made off and cap ended ( or a DOC ) the other side, with enough pipe to get a second clip on.

 

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PS, the manifolds are male - female ended so one screws directly into the next to daisy-chain them together. 

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so......

 

The main benefit of this type of setup is maintainable pressure at all outlets? 

Presumably the main drawback is the sheer amount of pipe to feed each location?

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4 hours ago, Barney12 said:

so......

 

The main benefit of this type of setup is maintainable pressure at all outlets? 

Presumably the main drawback is the sheer amount of pipe to feed each location?

 

A choice people make when deciding upon how they want their system to perform ;). Having the shower flow / temp fluctuating during use is something people wish to actively negate, and the pipe is cheap enough tbh. 

1 hour ago, RandAbuild said:

Can you use underfloor heating manifolds?

 

As long as they're brass or stainless then there's no real reason why not, just that the isolations aren't ideally suited to mains pressure / control of. Personally I'd not recommend it. 

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Image ^^^^^^ looks like Hep2O '4-port valved manifold plated brass' 3/4BSP x 15mm, part no HX94T/15W. @ £58.34 list.

There also appear to be cheaper non-valved manifolds for 22 x 10mm.

Both types also available in 2/3/4 port versions. HTH

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OK no next potentially daft question.......

 

Why the short length of copper pipe on each branch?

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OCD :D

There was to be a plywood boxing-in to go directly above the manifolds and cover the cuts in the ceiling which are out of view. 

The problem was, how to fill the holes where the various pipes bent off into their different directions whilst maintaining fire cell qualities and basic neatness. The only reason for the stubs of 15mm copper was that's where the plywood was to be finger-cut to go over the pipes, thus not allowing melted plastic to compromise that transition. The 10mm's to the right hadn't yet been doctored to suit yet as this was the early stages of commissioning and testing and I was pushed to get some services working ( get the downstairs cloak wc working so the portaloo could go etc ) so I just needed to pressurised the manifolds and try's things for leaks. 

 

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1 hour ago, Auchlossen said:

Image ^^^^^^ looks like Hep2O '4-port valved manifold plated brass' 3/4BSP x 15mm, part no HX94T/15W. @ £58.34 list.

There also appear to be cheaper non-valved manifolds for 22 x 10mm.

Both types also available in 2/3/4 port versions. HTH

 

They were cheaper than that when I bought them, circa £30 for the 4-branch iirc. A quick ring around the merchants would get a proper price as nobody ever pays list price unless they're lottery winners. 

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@Nickfromwales, thanks we found the Hep2O brass manifolds on eBay, etc..  I was thinking of doing the extract from the eBuild post where you posted this pic originally, but of course DB has now removed the ability of registered eBuild members to view pictures, so the pic itself was lost except from memory.  I was also planning to replicate something like this : 6+6 high flow (H+C) and 6+11 low flow (H+C).  There's a lot of low flow colds -- but that's because it doesn't seem to be worth the hassle of doing local Ts and tapping toilets off wash basin colds.

 

As far as I can see you main copper runs are 22mm rather than 28mm.  I can't see any reason for going up to 28 if you have a pressurised system at 2 bar-ish.  

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The only reason for 28mm in that job was because of the accumulator. ;)  

22mm is fine on a non-acc install. No,point in going over what your cold main will deliver / is sized at. You can only get a pint out of a pint jar :)  

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Oooooh I have another question [sticks hand in air excitedly :)]..........

 

So if you use these manifolds for each hot and cold outlet does that negate the need for isolation at the tap? Seems to be a good solution for maintanence at each fitting? 

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Yup, one of the major benefits. That job had semi-pedestals at each basin so more of a pita to get at them later. The other major benefit is being able to leave rooms isolated if they haven't yet been first fixed and then bringing them online, one feed at a time, to check for leaks / commission. 

Very handy in a part-complete build as you don't have to keep draining down and interrupting the water supply to already connected outlets. 

There was another 2-port manifold at the bottom of that pic ( yet to be fitted at the time iirc ) which serviced non-softened water. One to the boiler filling loop, and one to the kitchen sink cold tap ( for filtered water tap & cooking quality water ) plus it also tee'd off at the kitchen sink and supplied the outside tap. 

In an installation with a softener and an accumulator, the point where you tee the outside tap off from is of critical importance. It needs to be directly after the incoming cold stopcock and before the non-return valve of the accumulator**, or multi-block of an UVC arrangement. The outside tap should be before any pressure reducing measures so it influences the cold pressure to the house as little as possible. 

**You don't want the outside tap to be using stored energy from the accumulators, 

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@Nickfromwales, just walking though your layout about I can understand the first TMV, but why cascade in a second for the low flow hots?  Was this so that all of the washbasin hots were at a lower hand-hot temperature?  If so, then I take it that you only dry-shave? ;)

 

Also, Is there any specific reason from mounting the TMVs horizontally and standing out of the layout plane -- other than your drive for neatness?

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Sorry for any night terrors, but I wet shave in the shower ;). Smoother than Ghandi's heel :)

 

The only thing id do differently from that pic, with hindsight and no pressure being a wonderful thing, would have been to put the secondary tmv immediately off the TS hot outlet. 

Upon reflection, and with 28mm hot pipework before it, there may have been a bit too much 'dead' cold water to draw through everything ( as it is there ) thus offsetting the benefits of running 10mm to the basins. 

It was a tricky install actually, with both high flow dhw plus energy efficiency being thrown into the remit. At the time my assumption was that the leg of 28 before the first blending valve would never be 'stone' cold, and the subsequent design was born. I don't loiter after jobs so can't really report on the actual outcome, but I'm reasonably sure that the TS, being kept hot 24/7, would have allowed a bit of heat to escape and reside in that first leg thus reducing the 'issue' somewhat. 

That install was done 'on the fly' so not too bad considering. 

Tmvs can be mounted in any orientation, I just wanted that as easy to lag as possible, hence the Munson rings to space the pipe from the ply etc. 

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Fwiw, if there's no dependant kids / infirm occupants you can certainly do away with the second tmv if you wish. The tmv should be set around 50oC anyway so not going to cause issue for a normal household tbh.  

Personally I just like the hot water comfort of flicking the tap to the hot position and opening it and getting the exact same flow and temp each time regardless of what others are doing with outlets elsewhere in the property. Can't be arsed setting the temp, then it stabilises, then having to set it again, a proper pita.  

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The only online stockist of the Hep2O brass manifolds that I can find is selling the old grey version (HX93T/15 GY) parts, rather than the current white (HX93T/15W) parts.  The good news is that they are only £27.88 ex VAT, but the bad news is that Wavin have made design changes between the grey and white Hep2O versions:

  • The white version demounting key doesn't work on grey fittings.
  • The insert design has been changed and now includes castellations to give positive feedback on insertion.

I am not sure what the other implications are.  I could always resort to ringing round traditional suppliers such as TP, but I suspect that I'll be quoted a lot higher prices.  My inclination is to go with the GY parts and if necessary do the same trick as @Nickfromwales did in his layout shown above and put in a copper fire break.  The Hep2O straights are pretty cheap (~£1.20) and this means that I can still demount the Hep2O pipe if necessary.  Comments?

 

PS.  They do the 2 port W parts so I could use 3 × HX92T/15 W (£52.38) instead of  2 × HX93T/15 GY (£55.76).  Also time to do what Nick suggests and ring around a few plumbers merchants.

Edited by TerryE

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The grey old style fittings worked perfectly well, are fully compatible with the new system and can easily be dismantled by hand so I don't really see the point of going to the trouble of adding a short length of copper and then a coupler. Just my 2p's worth. 

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The point is to stop a fire melting the pipes and travelling through to the first floor joist space ;)

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The grey stuff is compatible with most 15mm stuff, but does have the Achilles heel of being able to be rotated until the joint comes apart. One of the things I hate about JG but ok if you can leave these exposed and confirm their state prior to commissioning.

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@Nickfromwales the whole issue of fire barriers and BReg compliance is a subject in its own right and merits is own topic.  I'll do a little background research and start one :)

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It's something that gets overlooked when cutting holes in buildings / walls / ceilings tbh, so feel free :) 

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I am about to start making up a similar manifold myself.

 

I understand the desire for performance (particularly on the hot side), but is there the need for performance when filling a WC?

Is there any reason why I couldn't run one/two pipe(s) from the manifold and T off to each of the 5 WCs planned in my house?

 

In our current house there are 3 WCs = basins teed off one pipe and it seems satisfactory.

Presumably this would mean I would also want to fit an isolation valve just before the pipe reaches each WC.

Am I missing something?

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