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Another DHW / DCW / UFH design


TerryE

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Good point, Nick, I was unaware that some pressure reducing valves already have a gauze filter to prevent the "crud" problem.

 

Is there a list somewhere of those that do, and those that don't?  If so it could be handy.

 

The two I have don't have gauze filters, I'll try and see if I can get the manufacturers names tomorrow.  There are both the same, Italian made, 22mm compression fitting, eith a very fine thread.  I've had one apart so know there's no filter in it (and, before you ask, I took it apart because I accidentally wound the adjusting  screw off the end of the thread - my excuse is that it was in a very awkward place to get at!).

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On 26/01/2017 at 18:23, Nickfromwales said:

In @TerryE's instance, the stainless steel gauze filter in the PRedV should be all the filtration required TBH. If, post PRedV, the fill point is drawn for the heating / HP etc then that primary measure should suffice. 

Probably as good a place as any to impress upon folk the need to strip and clean these filters / strainers directly after commissioning, and again after about a month or two of normal service ( use ). Any crap in the incoming supply (new MDPE etc.), or solder, flux, PTFE tape and jointing compounds can get to / and sit on the valve seat and cause it to malfunction. The effect of that failure is for mains pressure to get past the non-sealed seat and damage upstream equipment. :(

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What would be really useful for people like @joe90, @jamiehamy and me would be to some of those that have been through this such as @jack, @Calvinmiddle, @JSHarris, @PeterW, @PeterStarck just list off their feed stack in terms of components used that is from the MDPE coming in to the split of feeds to DHW and DCW, plus maybe any comments on any retrospective +/-s.

 

And not forgetting the pros here like @Nickfromwales

Edited by TerryE
Got to add the man to the list !!!
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Terry that is a brilliant idea, no reason to re invent the wheel so to speak, I personally would be very gratefull for any recommendations as I can "do" plumbing and understand many principles but by no means an expert.

 

For example Terry I have no idea whatsoever what you are talking about in your thread on modelling your slab ?.

Edited by joe90
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12 hours ago, joe90 said:

Good point Nick I will note it for my build, do you think there is a real need to perhaps diary, say annually, to do the same check/clean?

 

All I can say is that I had cause to check three Y strainer filters in our installation, when I re-jigged all the plumbing around to accommodate the Sunamp PV, and I removed two pressure reducing valves at the same time, as I lowered the overall system pressure to between 3 and 4 bar (one advantage of having a borehole system).  All three gauze filters had crud in them, almost all of it installation-related.  I was a bit surprised, as I was careful to keep everything clean, but tiny bits of PTFE tape and a few small bits of copper were caught in the gauze filters.

 

I now only have two Y strainers, and I did check the incoming "mains" one a few months ago, perhaps a year after I'd last had it apart.  It was as clean as a whistle, so I think the major problem is installation-related crud, rather than anything coming in later.

 

Having said that, we are on a borehole supply, so no one but me ever messes with it.  A mains supply may well have the same sort of issue with stuff that gets washed in from water company maintenance elsewhere. 

Edited by JSHarris
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46 minutes ago, TerryE said:

What would be really useful for people like @joe90, @jamiehamy and me would be to some of those that have been through this such as @jack, @Calvinmiddle, @JSHarris, @PeterW, @PeterStarck just list off their feed stack in terms of components used that is from the MDPE coming in to the split of feeds to DHW and DCW, plus maybe any comments on any retrospective +/-s.

 

And not forgetting the pros here like @Nickfromwales

 

Good idea, Terry, I'll try and get a concise and readily understood list together later.  Right now I'm busy writing a blog article on domestic electrical installation earthing schemes.

Edited by JSHarris
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5 minutes ago, JSHarris said:

 

Good idea, Terry, I'll try and get a concise and readily understood list together later.  Right now I'm busy writing a blog article on domestic electrical installation earthing schemes.

 

Sounds lethal to me :ph34r: (Sorry, just couldn't resist!) 

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@jack, can you use for mod privileges to move this last post out of this thread onto the parallel Boffin's thread on the UHF / slab design.  What I poked you for here was a description of your mains riser chain, that is your stopcock / double check valve / filter / PRV and any isolation or drain valves; how you've configured this.

 

[@TerryE, I've moved the post to your other thread and deleted it from this one.  I'm leaving your post here for reference]

Edited by jack
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@TerryE

 

Cold Supply 

MDPE

25mm/22mm Stopcock

22mm tee to draincock

22mm PRV with strainer

22mm full bore lever valve (FBLV)

(Tee into 15mm feeding toilets - temporary until rainwater installed)

 

At UVC

22mm FBLV

Y Strainer

22mm Control Set

22mm PRV - feed to balanced cold on all taps w 22mm FBLV down to 22/15 for all feeds

UVC

22mm / 15mm tee (multiples) feeds to taps (isolated)

22mm to ensuite 3 way mixer 

22mm to bathroom 3 way mixer 

 

Think that's it - for various reasons the rainwater system isn't going in until it's all signed off (Anglian Water being one reason ..) so it looks like we have an unbalanced tee however if it stays long term it will get a 1 bar PRV, otherwise it's on a pump and filter set up. 

 

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33 minutes ago, PeterW said:

@TerryE ... draincock ... PRV with strainer ... 22mm full bore lever valve (FBLV)

Think that's it ...

Peter, what gets me is that I often can't find what I am looking for or I am spoilt for choice, and both do my head in.  So take two examples:

  • The draincocks.  I know when and where to use them.  I've end-fed soldered them in the past so technique isn't the issue. However I was searching Screwfx to buy a few and could find them: drain, too many hits; drain valve, too few and the wrong ones.  I had to know to call the bloody thing a draincock. Durrrhh!
  • PRV.  Again we are spoilt for choice so it would be good to know which actual model people have used.
  • Putting the bits together once you've bought everything is the easy bit, IMO.
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4 hours ago, joe90 said:

For example Terry I have no idea whatsoever what you are talking about in your thread on modelling your slab ?.

 

That's why it is in the Boffin's sub-forum :) but when JSH, ST and anyone else with informed views and I have reached a broad agreement to all the geeky shit and agree on conclusions, then I'll do a blog post summarising the "how to" in a blog post or mainstream topic.

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6 hours ago, TerryE said:

What would be really useful for people like @joe90, @jamiehamy and me would be to some of those that have been through this such as @jack, @Calvinmiddle, @JSHarris, @PeterW, @PeterStarck just list off their feed stack in terms of components used that is from the MDPE coming in to the split of feeds to DHW and DCW, plus maybe any comments on any retrospective +/-s.

 

And not forgetting the pros here like @Nickfromwales

 

I'm not able to help very much with this issue. I haven't installed second fix plumbing yet and only have a schematic that I did a few years ago. My DHW system is probably less common and not much help to anyone but here's the drawing. Back to second fix wiring for me.

 

DHW Schematic.jpg

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OK, One of the benefits of a manifold system is that we can do all of the pressure testing centrally.  So is the T&J setup as per various feedback from Nick et al.  I don't use the mains supply at the moment for anything other than testing.  So coming from the mains I have:

  1. MDPE - Cu 25/22 stopcock : 22 Cu Double check valve : 22/15/22 T to (2) and finally a length of 22mm with an elbow and draincock at the top to act as a sort of air catcher / mini expansion
  2. Short 15 to 15/15/15 up to (3) and down to (4)
  3. 15 isolation valve, 15 double check valve and a Monument Dry Pressure Test Kit (£30) pumped by a Halfords Metal Trackside Pump (£18)
  4. 15 T to draincock and (5)
  5. 15 isolation valve and tail with Hep2O straight to hep2o flying lead which connects to whatever pipe or assembly that I wish to test.

Most of these bits were old spares apart from the two price listed items so the setup was cheap and easy to make.   The main disadvantage is that this Munson gauge only measures to 4 bar.  But the set-up works well and the trackside pump is good for flushing out the test water so you don't leave drippy pipes after testing.     Thanks guys :)

 

TnJs-pressure-tester.jpg

 

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I am just going through the list of bits and pieces that I need.  Whilst for the common stuff like end-feed Ts and Elbows it makes sense and is just easier to buy in 10, there's some stuff lie the 3/4" BSP male to 22mm compression elbow that I need 4 off.  Just 4, and I am unlikely to need more or less, so if I go to Plumb Centre, say, which does a Pegler branded one at £10.58 inc VAT.   I can get generic ones online for about half this price (e.g. here on eBay at £5.50).  Both are brass components.  I really can't see what the problems are with going the one for half the price. Both are brass co1mponents; passive fittings, and as far as I concerned if the the connect the bits that I need connected and don't leak then what's the difference?

 

Any thought as to why I might be wrong here, or is there agreement on this approach?

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I've directly compared the cheap multi-buy fittings from Screwfix with a couple of very expensive Pegler fittings, and frankly it's very hard to see any difference.  I probably still have some are fittings around, and could take samples of the brass from each and ask a formed colleague to analyse them, but in general the finish of the fittings, neatness of threads etc is a pretty good indication of the quality.  I don't think I've ever had a problem with the cheap big bags of fittings from places like Screwfix or Wickes, certainly none that I can recall.

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On 29/01/2017 at 18:08, JSHarris said:

I've directly compared the cheap multi-buy fittings from Screwfix with a couple of very expensive Pegler fittings, and frankly it's very hard to see any difference.

 

Jeremy, I use Screwfix a lot for many reasons:

  • It's cheap compared to classic Builders Merchants (BMs) such as Travis Perkins.
  • I live between a couple of branches within 15mins drive and service is quick, and their opening hours are excellent.
  • I can buy online and know that the items will have been picked and waiting by the time that I get there.
  • IMO, they very rarely score below 5/5 for the quality and functionality at that price-point.

My only caveat is that for some things they've slowly been jacking up their margins over last few years for some lines.  For example in plumbing. their bulk 10×90° elbows are competitive but some of the other slow turnover items are maybe 30% more expensive than Internet plumbing specialist such as the one that Peter mentioned -- if you can afford to wait the extra 2-3 days for delivery.

 

 

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