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Setting Up A Gledhill Direct Cylinder For Hot Water

Discussion in 'Plumbing and Central Heating' started by Ross-Not-A-Plumber, 17 Jul 2021.

  1. Ross-Not-A-Plumber

    Ross-Not-A-Plumber

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    Hi there. Looking for a bit of help please.


    We have moved into a new house and inherited a gas immersion boiler (Vokera easi-heat plus) and a Gledhill ES Direct 150 Hot Water Cylinder.

    Everything was working fine and then we got hit with a massive electricity bill. £117 for 7 weeks electricity and 2 of those weeks we were out of the country. That's for two people who are usually at work.

    After chatting to a few people, they've said is your immersion heater on. It's a switch with an orange light on it. Sure enough, it was on. So turned that off. A day later we've got no hot water.

    The central heating timer has been set to off as it's summer and don't need the heating on. So I've now set up a programme for the heating to come on from 7am to 8:30am. Which I thought would heat the radiators (if not up to temperature) and put some hot water in the tank. But the cylinder started whirring at 7am and stopped at 7:30. The radiators warmed up but no hot water.


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    From what I understand, the bottom, white off-peak connector on the cylinder is wired into the wall switch. but that also works the immersion heater in there too as it has the orange light on the switch??

    But if I turn on, the on-peak connector, that will surely be even more expensive??

    Surely there is a way for the cylinder to be heated as per the programme set on the central heating timer?


    Thanks.
     
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  3. CBW

    CBW

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    Looking at that, you have a direct unvented hot water cylinder, which will need the immersion’s to deliver hot water. Bottom one should be used for off peak and top one should be a boost. If you leave them on all day, this is what’s costing you the money - they’re 3kw (usually) and it’s the equivalent of constantly boiling your kettle throughout the day. Your gas fired boiler must just be for the heating only. You might be better with a timer for the hot water.
     
  4. Ross-Not-A-Plumber

    Ross-Not-A-Plumber

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  5. Gasguru

    Gasguru

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    None of this makes any sense...you say you've got a Vokera Combi boiler and an electric only cylinder?

    The air seperator and pipework below the immersion switches are for an open vented heat only boiler...is it redundant?

    Why have you got a cylinder with a combi?
    If you wanted the higher water flowrates from a cylinder why is the cylinder direct and not indirect (that could be heated with cheap gas from the boiler)?

    Is there a tundish behind that cylinder (with the 2 safety valves running to it)?
     
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  6. CBW

    CBW

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    I’m not sure, you’d probably be better keeping the switches, and link in via a dedicated economy 7 time switch.
     
  7. dilalio

    dilalio

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    The Game is afoot, Watson!
    :D
     
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  9. Ross-Not-A-Plumber

    Ross-Not-A-Plumber

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    Hi there,

    I should have been a bit more accurate with the boiler name, it's a Vokera easi-heat plus v18. The manual says it's a "high efficiency open vent boiler"
     
  10. Gasguru

    Gasguru

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    So why has the wrong cylinder been fitted? An indirect cylinder using the boiler to heat the water is about 1/4 the price to heat compared to electric immersion heaters.
    Insulate the hot outlet pipe on top of the cylinder..it's continually leaking heat.
     
  11. Ross-Not-A-Plumber

    Ross-Not-A-Plumber

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    Thanks for the info.

    We moved in two months ago. The boiler was fitted around November last year and the cylinder was fitted about March last year. None of the manuals were left either. So everything is being pieced together as we go.

    When they fitted the boiler, it doesn't look they flushed the system either. We took a radiator off last week to paint behind it and the water coming out was jet black!
     
  12. flameport

    flameport

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    You could do that, but it's unlikely to achieve anything.

    Even if left switched on 24 hours a day, the water is only heated when it's actually needed - once the water is up to temperature, the heating element will be switched off by the built in thermostat.
    It will only switch on again once the water cools due to some of it being used, or if left for long enough due to heat losses from the cylinder.

    Heating water using electricity is very expensive. No timer or other controls can change that.
    The cylinder installed is one that would be used in an all-electric installation where gas or oil wasn't available, and would normally be used on Economy 7 or a similar electricity tariff along with electric storage heaters.
    In your case, there is no point in having E7 or similar, as it only saves money if a very substantial proportion of electricity use is overnight - that won't be possible with just a hot water cylinder.
     
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  13. Gasguru

    Gasguru

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    Agree there...the heat losses from modern cylinders are minimal (despite the combi fan boys).
    A timer will save a little but it is worth insulating the hot pipework on top of the cylinder as that's continually leaking heat.
    Even though gas is perhaps a 1/5 to a 1/4 the price of peak rate electric (me and Mrs GG are paying £12/month gas for the hot water) replacing the cylinder with an indirect version would still take a long time to recuperate the expenditure.
    Did you get the building control notices for the boiler and cylinder installations?
     
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