TerryE

Another DHW / DCW / UFH design

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Guys. Slight plea from a Luddite .......

 

This thread is not in boffins corner, so.....can we have JFLAT's (Just a Few Less Abreviated Terms) :) 

Either that or provide a glossary :) 

 

IGMC

TFYU

HAGE

 

Bar Knee

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12 hours ago, Barney12 said:

Guys. Slight plea from a Luddite

I tend to agree.

There are some almost generic abbreviated terms is common use, PV, ST and DHW.

 

But when we get to component level, it gets messy.

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TDR, ( too damn right) ?

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OK, here is the hot manifold also done:

TE-HotManifolds.thumb.jpg.b966a1b17d02078573669e4266e9c224.jpg 

 

Ignore the Hep20 connector to the left; that's just temporary for pressure testing and commissioning.  I'll replace this with the draincock later. The TMV fits onto the 28mm common where the 28mm compression endstop is currently fitted.  (There is extra insulation behind the panel and I am going to fit  a box around this lot for insulation.)  However we've got an issue that I would like some advice on.

  • I commented in an earlier post that our flow rate is over 35 ltr / min.  This is an understatement.  If you do a 6-second flow test with two buckets: the first is to catch the flow for a few secs whilst it settles down, then you cut the second bucket into the flow stream for the six second count, and the measure.  The flow rate is ~50 ltr / min. 
  • The picture shows the nominal high-flow to the left; low-flow to the right, but the flow out of the "low flow" taps is fearsome -- far too fierce for most of our basins. 

So we would like to throttle the low flows right back.  I don't think that the manifold valves are really designed for such flow throttling.  So I was wondering whether to put a restrictor or in or even a 15mm PRV set to 1-bar or so in order to drop the flow rate to the toilets and basins right back.  I realise that I'll need to redo the pipe work, e.g. in this hot case put take the flow around to the other end of the low-flow 2×3 manifold set on the right and this will give room for a PRV or a flow restrictor.

 

Comments?

 

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16 minutes ago, Barney12 said:

I'm sure the pro's will have a better solution but I used a couple of these in my last place to balance a hot and cold feed. Worked perfectly. 

 

http://www.wondervalve.com/

 

Quite a clever bit of kit - did it come with a WRAS marking on the packaging ..??

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16 minutes ago, PeterW said:

 

Quite a clever bit of kit - did it come with a WRAS marking on the packaging ..??

 

From memory there wasn't any packaging. They came in Jiffy bags. 

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We had to fit (and test) flow limiters on all outlets.  I just fitted flow rate limiting washers, cheap, easy to fit (and remove after inspection................) and do the job over a wide pressure range.

 

For a shower you can just replace the existing washer in the fitting with a flow limiting one, for a bit of pipe you need to fit the flow limiting washer in an adapter.  You can pay through the nose for adapters with ball valves on, but if you hunt around there are cheaper straight ones available.

 

The washers I used are like these, colour coded for flow rate in litres/min, over their working pressure range:

 

QS-V55459_1_mn.jpg

 

These work by the elastomer bit in the middle deflecting under changes in water pressure to open or close the peripheral water flow space, hence regulating the flow rate more or less independent of pressure.

Edited by JSHarris
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Guys, I'll have to go around with the likes, but I go to bed with a problem and wake up to a solution. Isn't this forum and its members brilliant! Thanks guys. :x:x

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Terry, if you want an idea of the massive range of flow restrictors like this, then this page (where I nicked the image above from) give a fair idea: https://www.qssupplies.co.uk/Taps/Taps/EcoHomeRestricters/Product/463.htm

 

There are literally dozens of suppliers of these things, as the water regs require that taps, showers etc be limited in flow rate for a lot of new builds.  Often fittings are supplied with the flow limiters already fitted, we found; our downstairs WC tap had one on already, for example.

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I am confused on this subject because no one has mentioned water usage, I asked the builder who said he was sure the water supply was good enough !!!!. Am I going to get clobbered after fitting the plumbing by the BI asking for info on what Taos etc I have fitted?

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18 minutes ago, joe90 said:

I am confused on this subject because no one has mentioned water usage, I asked the builder who said he was sure the water supply was good enough !!!!. Am I going to get clobbered after fitting the plumbing by the BI asking for info on what Taos etc I have fitted?

 

There's a water usage calculator for checking compliance with Part G of the building regs.  Basically it's a spreadsheet where you enter all the appliances and their known water flow rates or usage for some, like cisterns, and it spits out whether you pass or fail.  In our case we failed badly the first time around, so I fitted those cheap flow limiter washers, measured the flow rates again (bucket and stop watch method) and passed, and then put those numbers in the certificate to show compliance with Part G.

Edited by JSHarris
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Guest Alphonsox
3 minutes ago, JSHarris said:

 

There's a water usage calculator for checking compliance with Part G of the building regs.  Basically it's a spreadsheet where you enter all the appliances and their known water flow rates or usage for some, like cisterns, and it spits out whether you pass or fail.  In our case we failed badly the first time around, so I fitted those cheap flow limiter washers, measured the flow rates again (bucket and stop watch method) and passed, and then put those numbers in the certificate to show compliance with Part G.

 

Did anyone ever check for the existence of these limiters ? or is this another tick box for building control ?

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Just to add, the spreadsheet I used was nicked from somewhere else and modified slightly, but is compliant with the water usage calculation guidance from the Department for Communities and Local Government.  I've attached it to this post, but you need to change the suffix to .xls from .txt.

Water Usage Calculator - Master.txt

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@joe90, there are two issues here: one for you and one for the BInsp.

  • You might some taps, etc. where you want full flow (e.g. bath, showers, kitchen sink) where you want a decent flow rate, and the remaining ones where it makes absolutely no sense to have unlimited flow (e.g. toilet cisterns and hand basins).  This is what our master here, @Nickfromwales, classes as "high flow" and "low flow".  It makes a lot of sense throttling back the low flow so you don't get a cold dip in the shower when someone flushes the loo, or you don't get blasted from the bounce if you flick the basin tap to full.
  • The second is the tick-in-box exercise to pass the Part G provision.

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2 minutes ago, Alphonsox said:

 

Did anyone ever check for the existence of these limiters ? or is this another tick box for building control ?

 

Yes.  I had an interim building inspector (not the very nice bloke I'd had for the whole build) who was a right jobsworth.  Not only was I asked for the certificate, but I was asked to prove that the restrictors had been fitted.  In the end we settled on my taking a photo to show each being fitted..................

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I thought PartG was only applied now if it's in your Planning Permission..? Same with PartM..??

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No mention of either in my planning permission, but the senior building inspector who did the completion inspection was very hot on Part M compliance.  I also had to justify not having Part G3 sign off for the low volume, low temperature, low pressure, sealed system.

 

The jobsworth was just a person it wasn't worth arguing with, as if you "won" on one point he'd only have picked you up on something else!

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On 06/02/2017 at 22:23, Barney12 said:

Guys. Slight plea from a Luddite ....... This thread is not in boffins corner, so.....can we have JFLAT's (Just a Few Less Abreviated Terms) :) Either that or provide a glossary :)

 

@Barney12, I know that Nick has added few extras to our acronyms list, but I've also gone through this thread expanding any acronyms on my first use, so that if you read this start to end and don't forget any on the way, then all of the acronyms should be explained.

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Back to the flow regulation issue, I've been checking our taps and they all use a standard diameter aerator / flow limiter and increased flow restriction versions are cheaply available, so for any that fail the flow tests, I can swap them out for the test.  They all seem to have a preferred 1-5 bar rating and our 3 bar pressure is bang in the middle of this, so the whole "need to do flow restriction" is pretty much a non-issue if done at the appliance end.  Phew.  Another panic over.

 

However, with all of these restrictors around the place, having a decent clean filtered water seems a really good idea, so I want to find a decent limescale inhibitor and a filter that I can clean without having to do any major disassembly.  However, having looked into this there are no WRAS approved chemical filters for potable water, since these work by swapping out the calcium and magnesium ions in the water for sodium ions, and this effects both the taste and wholesomeness of the water.  The magnetic descalers seem to be based purely on pseudo-science and there is no real evidence that they do anything at all.

 

As to filters, the magic search term to use is strainer (thanks Jeremy) which yielded the business on the JTM site: Brass Strainer 22 mm.  Another step forward.  Where is your Welshman when you need him!

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We fitted a water softener, as the water was pretty hard, and as I have high blood pressure I plumbed in a bypass so that non-softened water went to the kitchen tap (where pretty much all drinking water should come from).  Because I did this as an afterthought (again..............) the manifold plumbing was already in, so I tee'd off the kitchen cold feed after the manifold and plumbed in the bypass there, closing the manifold valve to stop soft water getting through.

 

One consequence of this is that I can switch the cold supply to the kitchen from softened to non-softened simply by turning two valves in the service area.  I can say with confidence that there is absolutely no difference in taste either way - the water seems to taste exactly the same whether softened or not.

 

Because of the sodium issue, I looked at the concentration of sodium versus calcium in both supplies.  The amount of sodium in our softened water was was tiny, far lower than the concentration in milk and many other drinks.  I'm a fairly heavy tea drinker (although I've cut down a bit since having advice on this forums predecessor) so worked out how much additional sodium I'd end up ingesting because of the softened water.  The result was a bit under 1% of my normal daily intake, and I never add salt to anything, don't eat foods with added salt and generally have a much lower than average sodium intake than most people (comes from being diagnosed with high blood pressure when I was 34 years old, and treated for it ever since!).

 

So, my conclusion was that, for me, softened water added virtually no additional health risk.  It also makes a far, far better cup of tea!

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This has come up in the past, so I won't beat it to death again, but:

- the amount of sodium in softened water will depend on how hard the water was to begin with.  Harder water = more sodium when softened.

- it's not appropriate to compare the sodium content of softened water with that of milk, because sodium alone is not the whole story.  It's the balance between dietary sodium and potassium that's potentially a problem for those who are sensitive to sodium.  Milk has three times as much potassium as sodium (470mg/l Na v 1440mg/l K), so the sodium in milk can largely be ignored (indeed, the additional potassium may even help balance out excess sodium from other dietary sources)

 

That said, the risks of consuming sodium have largely been debunked: https://www.scientificamerican.com/article/its-time-to-end-the-war-on-salt/ 

 

I personally have no problem drinking softened water.  I occasionally drink from our bathroom tap overnight and it tastes perfectly fine.  For reference, our tap water is "slightly hard" at 140mg/l CaCO3.

 

Do check with your appliance suppliers.  We were surprised and a bit annoyed to learn that our boiling water tap supplier wouldn't guarantee the boiler if used with softened water.  While I was sure it would be fine, I prefer not to go against manufacturer recommendations with this sort of thing, so unsoftened it is.  After a year, we've had a little bit of scale build up on the outlet, but nothing serious.

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I agree with all of that, but find the boiling water tap recommendation a bit odd.  Ours was supplied with an under-sink filter head and a recommendation that a water softening ion exchange  filter cartridge be fitted if the water was hard!  I've just fitted a blank cartridge now, and had I known that we were going to end up with a water softener than I'd have left the filter head off and plumbed the thing in directly.  I still have the new ion exchange cartridge it came with, and it's just a pre-charged water softener ion exchange medium in it, the same stuff the window cleaning guys use.  Although the cartridge is intended to be a one-off use item, I dare say running saline through it would regenerator the ion exchange resin, just as it does in a softener.

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