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Discuss Megaflow 3 bar pressure reducing valve placement in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. Smithers

    Smithers New Member

    Hi,

    Have lived in our house for around 10 years and always had bad pressure if more than one tap is running, toilet is flushed etc(hot and cold). We have (what I believe to be) a mains pressure system with a non vented Megaflow cylinder.

    We are about to install a new thermostatic shower and mentioned this to the plumber. He had a good look for us and concluded that the Megaflow pressure reducing valve has been placed in the wrong position. Its currently right after our stopcock as the water enters the house. He has quoted us to move this to the correct position to where the cold supply enters our Megaflow in our airing cupboard. Does this sound likely? and the right thing to do?
     
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    He's right in one way but still legal and correct (just after main stop tap )

    Any chance of a pic of your unvented cylinder??

    Also before he does anything regarding the cylinder make sure he's G3 registered (unvented cylinder qualified)
     
  3. Smithers

    Smithers New Member

    Hi,

    Here you go. Hopefully its clear enough. When the plumber tested our flow rate, it was approx 8 litres a minute, when the toilet was flushed(downstairs) the kitchen tap right next to the house inlet dropped to around 5 litres a minute.

    Mega.jpg
     
  4. Smithers

    Smithers New Member

    Please see better pic...

    Mega2.jpg
     
  5. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    That's great and there's your problem an unvented cylinder requires 2 bar and 20 lpm min else you will have problems like your having

    Now the pressure reducing valve may be at fault and causing you to have a reduced flow rate, best to get your plumber to test the flow rate before the pressure reducing valve
     
  6. Smithers

    Smithers New Member

    Thanks Shaun, Our water into the house literally goes into a stopcock and then 15cms later the pressure reducing valve, so not to easy to test the pressure and flowrate before, but it does sound like him moving/replacing the valve is a good plan?

    Lee.
     
  7. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    If it's at fault then replacement sounds ok as for moving if it complies with regs don't see any point, makes sure all taps are balanced etc

    Do you know what size pipe and material you having coming in ?

    Also best to cap the open end after the ISO valve on the hot
     
  8. Smithers

    Smithers New Member

    The house was built 10 years ago, so its all relatively new. If I look where the stop cock come up from the floor, I`m sure its a blue hose type presentation(hope that makes sense)
     
  9. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Yep that's alk will be either 20 or 25

    May be a silly question is the stop tap open all the way open ?
     
  10. Smithers

    Smithers New Member

    It is, its one of the things we tested. The Pressure reducing value plastic handle has snapped off, so we have to use a pair of pliers to adjust it, but the plumber was sure both were fully open.

    Its probably also worth mentioning we have a water softener also connected right after the PRV, however when we bypass this, it does not seem to make any difference in the pressure we get(if so its very small)
     
  11. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    I would get your plumber to remove the valve and get a temporary piece of copper pipe and test the flow into a bucket least you know if it's the reducing valve at fault
     
  12. Smithers

    Smithers New Member

    Sounds like a good idea, since he has to remove it anyway! I`ll have chat, thanks for the advice, I`ll drop a note when we find out.
     
    • Like Like x 1
  13. Smithers

    Smithers New Member

    Hi,

    Just an update on this one. The Plumber moved the pressure reducing valve to the cold feed supply upstairs on the megaflow and it fixed the issue!!! Can now run two showers, flush the loo with minimal drop in pressure(it is noticeable but no where near as bad). Don`t understand the logic as to why, but happy its fixed.

    Lee.
     
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