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Discuss Mega flow system losing water pressure in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. Jmills

    Jmills New Member

    Firsr time post apologies if it's been covered.

    I had a mega flow system fitted 9 months ago and if I'm in the shower for example and flush the toilet the pressure drops.

    Same if I'm running a bath and turn the kitchen tap on, the pressure drops quite a lot.

    I had a total house renovation and my builder is scratching his head and saying it's just how it is.

    But I know that it's not.


    Any tips and suggestions would be appreciated.
     
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Easy what's your incoming cold water main pressure and flow readings ?

    And hope the builder didn't fit the unvented cylinder
     
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  3. Jmills

    Jmills New Member

    Hi. No idea. How would I find that out?

    Also the pressure is fine with just one tap running. Really good pressure.
     
  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    from the cold kitchen tap or outside tap how long does it take to fill a 1 or 2 l bottle (which ever you have handy)

    as for pressure you would need to get a pressure gauge

    http://www.screwfix.com/p/monument-tools-mains-water-pressure-test-gauge/82412

    attach to an outside tap
    and measure the standing pressure (with no outlets open)
    and dynamic pressure (with the kitchen tap open or one outlet open)

    hope this makes sense
     
  5. Jmills

    Jmills New Member

    12.5 seconds to fill a 2 litre bottle.
     
  6. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    theres your problem around 10lpm way way under what is needed for an unvented cylinder, spec is a min of 20lpm

    can you double check that measurement by using an outside tap
     
  7. Jmills

    Jmills New Member

    Previous was kitchen tap.

    Outside tap = 8 seconds for 2 litres
     
  8. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    thats better but still lower than needed for an unvented cylinder

    outside tap come out at about 15 lpm

    i would say incoming water main is your problem
    do you know what size and material type is it ?
     
  9. Jmills

    Jmills New Member

    No idea sorry. I'll have to get all that looked at.

    Someone else suggested an accumalator might solve it. Does that make sense?
     
  10. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    depends it would solve the drop in pressure when more than one outlet is open (wouldnt increase it) its an ok idea need to know what the incoming water main pipe is tho

    wheres your cylinder located?
     
  11. Jmills

    Jmills New Member

    Cylinder is in converted loft space, in its own room. So technically the 2nd floor(top floor) of my house.
     
  12. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    bit of a long shot any chance of a few pics of the cylinder and pipework etc?
     
    • Agree Agree x 1
  13. Jmills

    Jmills New Member

    2omm poly.
     
  14. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    stop tap open all the way up both of them?
     
  15. Best

    Best Trusted Plumber Top Contributor!!

    Wouldn't surprise me if a least one small bore isolating valve is fitted on mains supply or outlets. I don't trust builders and their plumbers
     
  16. Jmills

    Jmills New Member

    Plumber returned and he measured pressure and he's getting 21 lpm at the boiler. He's scratching his head as it should be more than enough pressure.
     
    Last edited: Sep 23, 2017 at 5:13 PM
  17. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Guess you mean 21 lpm ? As 21 bar would blow the cylinder up :D
     
  18. Jmills

    Jmills New Member

    Edited.

    Any ideas?
     
  19. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Do you know where he tested the flow from ?
     
  20. Jmills

    Jmills New Member

    Can't quite remember I think he said coming out of the system.
     
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