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Discuss Replacing stop cock, which size in the Valves & Taps area at UKPlumbersForums.co.uk.

  1. 1animal1

    1animal1 Member

    Hi, I am looking to change my stop cock to a 22mm version. I am currently getting everything ready for my unvented system and figured I'd get this done whilst I've got the floor up downstairs re piping the bottom central heating ring.

    The plan is to run the pipe into the adjacent garage which runs parallel with the hallway, so that I can line off to the necessary 15mm pipes going upstairs, and run to where the unvented will be situated at the back of the garage.

    I presume the blue pipe in the picture is a standard 22mm and I'll need and compression stop cock?

    Thanks
     
  2. scott_d

    scott_d Plumber GSR Top Contributor!!

    No picture
     
  3. 1animal1

    1animal1 Member

    Just trying to upload, won't open up the upload feature on my phone
     
  4. 1animal1

    1animal1 Member

    20170812_191816.jpg
     
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  5. scott_d

    scott_d Plumber GSR Top Contributor!!

    Its MDPE so wont be 22mm
    Are you piping for a balanced cold?

    Nice ballofix valve :rolleyes:
     
  6. 1animal1

    1animal1 Member

    Not sure what you mean by balanced?

    That's the only main into the house. Wanting to convert to 22mm as had read you need 22mm for unvented systems?

    Guessing this will be 20mm mdpe given the relative size to the 15mm

    It's a right mess isn't it :D I tried to tidy it up without repiping when refitting the downstairs toilet where it is situated. Knowing I'd have to take it all out again for the 22mm.. I was going to get my plumber to do that but figure I should be good if it's a simple compression fitting. That way it's all piped ready for the unvented install without me having to pull floors up again
     
    • Like Like x 1
    Last edited: Aug 12, 2017
  7. 1Steven

    1Steven Plumber GSR

    Bag o ***** re plumb.
     
  8. 1animal1

    1animal1 Member

    Googled it! And see what you're asking... Basically that the unvented is fed by the 22mm then all outputs balanced after the unvented? Presumably to ensure no one tap reduces flow on the rest
     
  9. 1Steven

    1Steven Plumber GSR

    Don't forget you're double check valve and doc for starters
     
    • Like Like x 1
  10. 1animal1

    1animal1 Member

    Doesn't all that get done with the unvented pipework?

    Plan is, get the 22mm off the stop tap into the garage. T off to the upstairs bathrooms/current cylinder. Then T to the kitchen and downside loo running new closer lengths to where the unvented will be. When the unvented is ready to go, all can be repiped from within the garage making it easier all round.

    Will this not work
     
  11. Jones82

    Jones82 Member

    It will be either 20mm or 25mm mdpe, first thing to do is check your boundary stop cock works as you'll need to shut this off first to work on or before the stop cock inside the house.
     
    • Like Like x 1
  12. 1animal1

    1animal1 Member

    Will do, thanks J.
     
  13. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

  14. 1animal1

    1animal1 Member

    Cheers Shaun... Any flaws in my plan to upscale to 22mm... About 7 metres to the unvented site
     
  15. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    No disrespect 1 animal get your plumber to do all the pipework it looks easy but what your trying is a bit tricky cheers kop .
     
    • Agree Agree x 2
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  16. 1animal1

    1animal1 Member

    No, i appreciate the advice kop.

    What's the complication, the compression stop tap or the connections afterwards?
     
  17. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Theres not alot of point stepping up to 22mm off a 15mm supply if you truly want a 22mm supply you will need a new 25 mm mdpe main connected externally you can only get out what you put in upsizing will 15mm will reduce your pressure and flow , do it once do it right . cheers kop
     
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  18. 1animal1

    1animal1 Member

    So the 20mm mdpe to 22mm is pointless when compared to the 20mm to 15mm I have now?

    I get that the pipe diameter to 22 is increased from the 20, and so reduced pressure

    Are you saying that an unvented system will need 25mm mdpe indefinitely?
     
  19. Matchless.plumb

    Matchless.plumb Trusted Plumber Top Contributor!!

    Did your plumber check the water pressure and flow rate as you require certain amount of pressure as well as litre per minute.
     
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  20. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    This is how it works 20mm mdpe to 15mm - 25mm mdpe to 22mm - 32mm mdpe to 28mm and so on .
     
    • Like Like x 1
  21. 1animal1

    1animal1 Member

    The pressure hasn't been measured properly, however it's not in question and my plumber agrees given what he has seen. It's easily above what is required for an unvented.

    Kop, I appreciate the issue in upscaling a pipe with regards to pressure drop.

    Am I correct in saying that my unvented needs a minimum of a 22mm feed... And if so, my only way to get this is to increase my main to 25mm? Given my 20mm predicament
     
  22. Matchless.plumb

    Matchless.plumb Trusted Plumber Top Contributor!!

    I hope you and your plumber know what they are doing. If not measured properly how do you know that you will have the right amount of pressure or flow rate ? I guess things like this should be fully checked before starting to think of an unvented cylinder. Some people Have 2.8 bar standing pressure but once you open a tap it goes down to 0.9bar so you really should check that
     
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  23. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Yes mate it is if you want the performance stated by the unvented cylinder manufacturer in their instructions , you can still go unvented just connect to what you have obviously you wont get the litres per minute of a 25mm 3 bar supply but it will still work just not very well its your choice in the end . cheers kop
     
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  24. 1animal1

    1animal1 Member

    Thanks match

    So far my plumber who is qualified to fit unvented has only carried out a service on the bag that is my current 1986 boiler. He asked me a few questions regards pressure drop before checking himself visually.

    My concern and reason I want unvented is because of pressure drop on the hot, that you get with most combis, which I don't seem to get on my current cold irrespective of what's being used.

    I admit it needs measuring properly... But the advice I've had so far, I'm happy with based on mine and their experience
     
  25. 1animal1

    1animal1 Member

    Thanks kop

    Sounds like the 20 versus the 25 will be really noticeable. This throws a huge spanner in the works given the work required to upgrade.

    Max I'll ever need to compensate for is 2 digital showers running. Can i survive on the 20, or do I need this 25..[/QUOTE]
     
  26. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    Download the installation manual for the cylinder you are looking at fitting it all in there bud cheers kop
     
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  27. 1animal1

    1animal1 Member

    I'll have to get hold of my plumber as it was his recommendation I was going with on the cylinder.

    Cheers for all the help. The intention was to get as much done prior to bringing him in around January time. Looks like I probably need more info before touching anything
     
  28. Matchless.plumb

    Matchless.plumb Trusted Plumber Top Contributor!!

    How many bathrooms do you have ?
     
  29. 1animal1

    1animal1 Member

    It's only a 4 bed with main bathroom, en suite. I had considered a second en suite but that's unlikely at this point.
     
  30. Matchless.plumb

    Matchless.plumb Trusted Plumber Top Contributor!!

    So basically you've got 2 bathrooms, if so you should be able to supply to bathrooms with a combi boiler.
     
  31. 1animal1

    1animal1 Member

    I've covered this with my plumber, I want the hot at mains pressure for a proper shower experience that a combi cannot provide. Unless the newer combis can provide that sort of pressure now to support an electronic power shower mixer?
     
  32. Matchless.plumb

    Matchless.plumb Trusted Plumber Top Contributor!!

    A combi boiler is able to provide you a decent shower without lack of water pressure unless you open 2 showers in the same time then the boiler will provide you half. Which means if the boiler will give 16lpm you will only get 8lpm at the shower. Other than that there is no issues.
     
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  33. 1animal1

    1animal1 Member

    That's the biggest issue, the drop off when using any other mains hot water source.

    I have considered both and obviously don't want to spend more than I need to, but the unvented seems to tick all the boxes.

    The final system will be a 2 zone with hot water and respective nest control. That's what I've settled for and what I am halfway through piping for... Although a bit of a pita as I'm having to pipe as I want it in its final guise, but then link it all together to work now with the current set up... Bags of fun :)
     
  34. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    get the flow rate and pressure and then come back to us
     
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    • Agree Agree x 1
  35. 1animal1

    1animal1 Member

    Will do Shaun
     
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