1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Combi boiler and unvented cylinder

Discussion in 'Plumbing and Central Heating' started by CB750K2, 7 May 2021.

  1. CB750K2

    CB750K2

    Joined:
    11 Feb 2020
    Messages:
    24
    Thanks Received:
    0
    Location:
    East of England
    Country:
    United Kingdom
    I want an unvented hot water cylinder with immersion heater in case my Vaillant Eco Tec 831 plus combi boiler fails and we can at least have hot water until it gets fixed.

    I recently had the Vaillant serviced by a Heating Engineer who said there is no need to turn the Vaillant into a system/heat only boiler to achieve this.

    He said a manual control could be installed on the hot water side which when the boiler fails the control could be turned on to supply hot water to the taps from the unvented cylinder.

    Is the heating engineer correct ?

    If so would someone describe more accurately than I have done how this is achieved.




     
  2. Sponsored Links
  3. DP

    DP

    Joined:
    10 Dec 2003
    Messages:
    14,129
    Thanks Received:
    3,081
    Location:
    Glasgow
    Country:
    United Kingdom
    Waste of time at this late stage.
    I would have suggested a small combi to supply hot water needs for kitchen and UV for rest
    Can be done with your present boiler too
     
    • Thanks Thanks x 1
  4. ianmcd

    ianmcd

    Joined:
    15 Aug 2010
    Messages:
    21,491
    Thanks Received:
    8,374
    Location:
    Lanarkshire
    Country:
    United Kingdom
    and then you woke up, absolute rubbish
     
    • Thanks Thanks x 1
  5. Zundapp

    Zundapp

    Joined:
    19 Feb 2021
    Messages:
    11
    Thanks Received:
    0
    Location:
    Royston
    Country:
    United Kingdom
    Another small combi is an interesting idea ... does UV for rest mean the small combi would supply hot water for the bathroom basins and shower ?

    Would the heating engineer disconnect the current combi from the hot water pipes so it would never fire up for hot water ?
     
  6. CB750K2

    CB750K2

    Joined:
    11 Feb 2020
    Messages:
    24
    Thanks Received:
    0
    Location:
    East of England
    Country:
    United Kingdom
    When you say
    do you mean the Heating Engineer who suggested this is talking rubbish ?
     
  7. DP

    DP

    Joined:
    10 Dec 2003
    Messages:
    14,129
    Thanks Received:
    3,081
    Location:
    Glasgow
    Country:
    United Kingdom
    Small combi for kitchen and utility, cylinder for bathrooms and showers. 30kw combi is adequate for a shower. Any combi is better than an electric shower
     
  8. Sponsored Links
  9. ianmcd

    ianmcd

    Joined:
    15 Aug 2010
    Messages:
    21,491
    Thanks Received:
    8,374
    Location:
    Lanarkshire
    Country:
    United Kingdom
    either he is or you didnt understand what he was saying, if you want that system you feed most outlets from the UVHW cylinder and just the nearest outlet from the combi, why have an UVHW cylinder sitting cold and breeding legionella in case your boiler breaks down and you cant boil a kettle
     
  10. CB750K2

    CB750K2

    Joined:
    11 Feb 2020
    Messages:
    24
    Thanks Received:
    0
    Location:
    East of England
    Country:
    United Kingdom
    I may well have misunderstood what the heating engineer said but will speak to him next week and will let you know.

    This is what I thought he said:

    • Leave the combi boiler just as it is now to supply heat to the radiators and hot water to the taps, bath and shower.
    • Instal a diverter on the cold mains feed so that it can either point to the combi boiler or point to a new unvented cylinder.
    • Instal another diverter on the hot water supply to the taps,bath and shower which can either point to the hot water output form the combi boiler or the hot water output from the new unvented cylinder.
    So when the combi boiler fails and is turned off, I can use the unvented cylinder to supply hot water for the bath, shower or kitchen washing up.

    We can live without heat should the combi fail but still want a hot water supply to the taps, bath and shower until such time as we can get a heating engineer to come out and fix the combi …. In the depths of winter this can be quite some time as you all know how busy you can be !

    If you have a different or better solution to having a fall back hot water supply to the taps, bath and shower, please let me know.
     
  11. ianmcd

    ianmcd

    Joined:
    15 Aug 2010
    Messages:
    21,491
    Thanks Received:
    8,374
    Location:
    Lanarkshire
    Country:
    United Kingdom
    just fit an electric shower in one bathroom /en-suite, hardly rocket science, are you really saying that you couldnt survive for a few days without hot water when you can boil a kettle ? heat a pot of water? wish you were my customer , I would install 3 unvented cylinders in case the first two dint work after years of never being used
     
  12. CB750K2

    CB750K2

    Joined:
    11 Feb 2020
    Messages:
    24
    Thanks Received:
    0
    Location:
    East of England
    Country:
    United Kingdom
    I can live without hot water no problem but it is the others in the house who can't.

    I lived in a flat and when the hot water failed, I put 4 saucepans on the stove and carried them in to the bath for each person to wash so they coulld all get a wash before work.

    That was easy for me as I was younger and fitter then and it was on the level. At my age now (don't ask !) I wouldn't want to carry pots of boiled water up the stairs in our house. At the moment I can't hold a full kettle just using one arm due to my elbow giving out and various other injuries.

    Your suggestion of an electric shower is a good one or possibly an electric instant hot water heater over the sink.
     
  13. ianmcd

    ianmcd

    Joined:
    15 Aug 2010
    Messages:
    21,491
    Thanks Received:
    8,374
    Location:
    Lanarkshire
    Country:
    United Kingdom
    if you are indeed on the level , you wont wait a whole day to get it sorted :rolleyes: as for an over sink water heater , put a kettle near the sink, how do you think most of the country survive if ther boiler breaks down ?
     
Loading...

Share This Page