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Discuss Vertical vs Horizontal Unvented Tank for Loft Conversion in the Plumbing Forum area at

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  1. ebgt

    ebgt New Member

    disclaimer - just a homeowner looking for advice


    Was looking through old threads and found one that dealt with the pros and cons of horizontal un-vented cylinders - but the last post on it was a while back and I was wondering if people's views (& the the appliances) had changed much.

    We're having a loft extension built with an ensuite. We've had a new combi installed in the kitchen - but we're not happy with the amount of hot water it's pushing out and the builder has advised that we could improve the situation by installing a horizontal unvented cylinder (the only room to put it in is under the eaves).

    He's recommending ones made by Joule (Cyclone Horizontal Un-Vented Cylinders - Joule)

    We've been told (and I've read) various thing about them ranging from "all horizontal tanks are useless) to "they're great". Does anyone here have an informed opinion?

    From what I understand there's no issue here with the water pressure or rate of flow - but I'm not expert.

    Any info greatly appreciated.
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Need to be sized correctly (50% bigger than required capacity)

    But there great
  3. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    They are not as good as vertical cylinders but are more than suitable for say 98% of jobs. I would say straight off ignore whatever the builder says you need to be G3 certified to work on and install these. Insist on getting a qualified engineer in to assess and quote
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    • Agree Agree x 1
    Last edited: Mar 29, 2018
  4. bogrodder

    bogrodder Plumber GSR Top Contributor!!

    Or he could install a Telford horizontal one and fit a bronze pump as per there recommendation s, then could get a normal sized one calculated to their requirements.

    Also the extra weight ..maybe 300 kilos from the cylinder, would probably require calculations from a structural engineer.

    And finally plenty of room for the annual safety check
    • Like Like x 1
  5. dan_the_plumber

    dan_the_plumber GSR

    Horizontal cylinders do almost the same job as a vertical cylinder. They just lend themselves to limited head room in attics and spread their weight across more ceiling joists.
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