Advice on unvented cylinder

Discussion in 'Plumbers' Talk' started by fronnie_5, Feb 12, 2009.

  1. fronnie_5

    fronnie_5 New Member

    Hi all,
    I have been asked to plumb a house out, new build. Slightly bigger than average. It has 5 bathrooms/ensuites and two downstairs sinks and toilets. I am just after a bit of advice on the best unvented cylinder for this. I am piping it it up with a secondary return for the hot water using a Bronze pump. Any advice will be greatly appreciated.
  2. Captain Leaky

    Captain Leaky New Member

  3. Switcher

    Switcher New Member

    Five bathrooms?
    I doubt if get mains pressure to supply that little lot.
    Sounds like a job for pumps or gravity supply.
  4. imran_

    imran_ New Member

    Eh?? Mains pressure is mains pressure - it doesn't change if you have more bedrooms??

    Gravity supply - now there's a thought.. No.... hold on... it isn't. WTF???
  5. Bonedry

    Bonedry New Member


    The OP was asking for advice not ridiculous waffle.

    If its unvented that you are going for I would go for at least 300lts or even linking 2 units together.

    As the Captn says the Megaflo site has spec on linking cylinders together.
  6. Switcher

    Switcher New Member

    Ridiculous waffle eh?
    What good is an unvented cylinder if the mains flowrate is 10L/min?
    I suggest the OP checks this out first!
  7. doing a bit

    doing a bit New Member

    if you are fitting a secondary you will need a connection on the unvented cylinder for it, so whatever you order make sure of the availability of connections ;)
  8. doing a bit

    doing a bit New Member

    I suggest the OP checks this out first!

    as its a new build and therefore new mains connection make sure you get a big cold mains to cope with the demand potential, not the usual 25mm ;)
  9. Switcher

    Switcher New Member

    Try the Wilo secondary pump. Has timer,stat,nrv built in. Fitting one tomorrow on a 300/L oso.
  10. Easy Life

    Easy Life Member

    work out your hot loading units for the whole house, that will give you the minimum cylinder size, also check your avaliable mains pressure & flow rate.

    i think you will probably need to install Equa-Flow System.

  11. rome60

    rome60 New Member

    First thing use Megaflo cylinders the best,my advise is use two cylinders either link them together or if the bathrooms are fairly localised separate the cylinders to serve part downstairs & upstairs.The other cylinder can be sited elseware to serve three bathrooms.Regarding the secondary return with the Megaflo the connection for that is on the mains cold inlet.Another thing to consider is with the secondary return the pipework really requires insulating,this depending on the type of joists being used can be a problem.Although the domestic return can be on a timer,when circulating for long periods it is chilling the water in cylinder making the boiler fire up.Also is the 5 bathrooms having 5 baths or possibly 2 baths & 3 showers in E/Suites that helps when sizing the cylinder capacity.;)
  12. imran_

    imran_ New Member

    The secondary return must be insulated (Part L). Personally I'd go for an Oso or Vaillant model rather than a HS. The megaflos are OK, but not at the price premium. Plus, the bubble is forever being lost AND makes the cyl higher. Bottom line, a SS cyl is a SS cyl, just factor in what's included and what isn't
  13. mantor

    mantor New Member

    I agree with you about the price premium/ is it worth it thing imran, but we got a 210 ltr megaflo about six years ago and it's never needed the bubble re-bubbling yet.
  14. rome60

    rome60 New Member

    Agree with mantor only occasionly they require recharging simple to do,i have been installing Megaflo cylinders many years agree they are expensive but you get the best.Have replaced other makes due to being faulty or poor delivery pressures never had a fault with Megaflos.

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