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Discuss Why disconnect an immersion heater? in the Plumbing Forum area at

  1. batwad

    batwad New Member

    I moved house a few months ago and am slowly but surely figuring out its nuances. Wouldn't it be wonderful if houses came with wiring/plumbing diagrams that showed how everything connected? Anyway...

    I've got what I understand to be a pretty standard gravity-fed vented heating system, with gas boiler and hot water tank in the airing cupboard and cold+expansion tanks in the roof. The boiler was fitted about seven years ago and it looks to me like the fitter stole the electricity supply for the immersion and used it for the heating and boiler controls!

    Tracing the cable back from the immersion, it goes into a time clock and from there into fused isolator and that's where it ends. Below this is another, a 2.5mm cable feeds a newer isolator for the boiler and heating controls. The immersion, timeclock and old isolator are dead having been bypassed.

    My question is this: why would you bypass the immersion when fitting a new boiler? It's not unusual to have an immersion supplementing gas is it?

    Ultimately I'm thinking of reconnecting the immersion and using cheap Economy 7 electricity to heat the water. Is this a Bad Idea?
  2. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    Gas is cheaper
    • Agree Agree x 1
  3. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    Your immersion is usually used as a backup incase the boiler fails, not to supplement it. It also may be disconnected if it doesn't work.
    • Like Like x 1
  4. YorkshireDave

    YorkshireDave Plumber Top Contributor!!

    Cheaper per KW but less efficient...

    Many reasons. Some are:
    - Immersion faulty so did not want to pay for new
    - CBA
    - Cheap job

    Believe me if the original owners had even an inkling of selling they'd have got the cheapest of jobs done in my experience.

    If you wish it reinstating, then its should not be too difficult a job. However the element must be tested prior to doing so as water and electrikery do not mix ;)
    • Agree Agree x 1
  5. Pickwickpick

    Pickwickpick Plumber

    As Riley says gas considerably cheaper, you're looking at around 3p per kWh for gas, off peak economy 7 is at best going to be 7p per kWh and then it more than doubles during peak time so all the things you use during day would be noticeably more expensive to run.
    • Like Like x 1
  6. BYP


    I’d personally recommend connecting it again although not though economy 7 and just using a 20 amp switch, so if you need hot water and the boiler is not working you have it.
    • Useful Useful x 1
  7. Rob Foster

    Rob Foster Top Contributor!!

    lecky is cheaper to maintain than gas ...its horses for courses
    ultimately there is no real 'free' market in energy.its an illusion distorted by the big boys , government interference, and unfair green tariffs , roll on hydrogen enhanced natural gas
    Rob Foster aka centrakheatking
    • Like Like x 1
    • Agree Agree x 1
  8. Pickwickpick

    Pickwickpick Plumber

    Good point re cheaper maintenance, its not an easy one to quantify, especially as eco 7 then increases cost of electric for e.g. computers, lights and anything else that has to be used during peak times, there's a lot to take into account!

    By its very nature there can't be a true free market or genuine competition with utilities, so we end up with worst of all worlds.
    • Like Like x 1
  9. Rob Foster

    Rob Foster Top Contributor!!

    The energy market is totally distorted , one neighbour is subsidising another, and both consume simlar kw each year.
    whilst dwelling in identical units . smoke and mirrors
    and then there are the naughty tarrifs that punish poor people
    ...aww its a mess
    centralheatking aka Rob Foster
    • Like Like x 1
    • Agree Agree x 1
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