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Should I change to a combi boiler?

Discussion in 'Plumbing and Central Heating' started by Richhen, 14 Mar 2020.

  1. Richhen

    Richhen

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    Hi, looking to replace 30 year old boiler (standard gravity fed system).

    I have just learned that replacing like-for-like will require an upgrade to a pumped system to comply with new regulations so I can control heating and hot water separately.

    From the quotes I have, this upgrade makes the like-for-like replacement significantly more expensive than just switching to a combi boiler and getting it relocated to the airing cupboard at the same time (would be quite desirable).

    I hadn’t intended on switching to a combi, but this seems the better solution (practically and financially) all round.

    Any experts able to give me the confidence to go for it? I’m a bit nervous about making the leap!

    Thanks
    Rich
     
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  3. Hugh Jaleak

    Hugh Jaleak

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    Combi's aren't the ideal solution for everyone. Yes, they free up space, (but if you like an airing cupboard, then alternative provision has to be made), if it breaks down you have no hot water or heating, a bath can be slow to fill, (and heating isn't running whilst the hot water demand is present), and most will struggle to feed 2 hot outlets at the same time. Most operate on a pressurised system too, so if your rads and pipework are the same age (or older) than the existing boiler, be aware that pressurising could cause issues with pinholes in rads/pipework. Certain manufacturers products seem to be more reliable, so choice of boiler is also a consideration.

    Stored hot water gives you the advantage of having immersion heater backup in the event of boiler breakdown, can allow feeding of multiple outlets simultaneously, and will allow for quicker filling of a bath, (modern cylinders will reheat whilst occupant in in the bath, so technically should be enough for another bath once 1st person has finished).

    Both have pros and cons, but do your homework before deciding I think is the best advice.
     
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  4. martin hill

    martin hill

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    Just got a potterton Titanium 24 heat only to replace my baxi. If going for the combi like you say it 4 pipe connection involved so its a bugger if you want it miles away from suitable connection point. Hugh hit the nail on the head. Write down what you want your boiler to do and check out the different brand sites and compare.

    One thing is Combi and system use pressurised instead of gravity so do you think your pipework joints are upto it as well.
     
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  5. ianmcd

    ianmcd

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    All depends on your HW requirements
     
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  6. Madrab

    Madrab

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    Yup, my sentiments exactly. It all depends on how much hot water you want.

    Changing to a fully pumped system can still give you a boiler in a box sized like a combi, it's a system boiler, that contains all the components in the same sized case as a combi but it just doesn't have the instantaneous hot water element. Even then you could have a combi and still keep the stored hot water facility.

    Ideally you want an experience engineer in that can explain the benefits and drawbacks of each system to enable you to make an educated decision to suit your needs.
     
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  7. durhamplumber

    durhamplumber

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    The general thinking is,if you are only likely to use 1 bath or shower at a time,a combi is fine
     
  8. Gasguru

    Gasguru

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    And if you can cope with the inconvenience of having no hot water when the boiler packs up a combi is fine.
    In these current times I would want the backup of an immersion...
     
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  9. bernardgreen

    bernardgreen

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    and no one will helpfully do the washing up while you are in the shower then .

     
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  11. durhamplumber

    durhamplumber

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    Generally Bernie it is not that big a deal!!....My wife tends to know if i am about to shower!!..
     
  12. durhamplumber

    durhamplumber

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    Lol....and if the lecky goes off?......coal fired back boiler too????...And wood incase you run out of coal.........
     
  13. DP

    DP

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    I think a gas fire should suffice, have installed combis with hot water cylinder.
    Simpler the setup, better it will be. With that in mind, combi is a non starter.


    Why not change boiler like for like and replace the cylinder too which possibly 30 year old?
     
  14. Gasguru

    Gasguru

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    Why would the electric go off...99.9999999% of boilers failing is not due to the power station failing.
    Perhaps if you repaired boilers day in....
     
  15. Richhen

    Richhen

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    Thanks.
    What benefit do I get from replacing the cylinder? I (probably wrongly) assumed it’s just a vessel holding hot water so wether it’s 1-year or 50-years old it doesn’t matter? Do modern cylinders do things differently?

    Also, is a combi with a hot water cylinder the ideal solution - ie less space, pressurised showers, stored hot water in case of failure etc

    Thanks
     
  16. Richhen

    Richhen

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    Thanks.
    Is there a benefit to changing the cylinder too? I (probably wrongly) assumed it’s just a vessel containing hot water so does it really matter if it is 1-year or 50-years old? Do modern cylinders do things differently or bring new advantages?

    Also, is it the case that combi with cylinder is the best all round solution ie space saving, hot water on demand, stored hot water to run to multiple outlets and in case of failure, mains pressurised showers etc?

    Thanks
     
  17. Mottie

    Mottie

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    My new cylinder heats up quicker than the old one it replaced and it’s much better insulated - gives off no warmth at all and we have to now rely on the heat from the pipes in the airing cupboard to air the clothes. Why not go heat only boiler in a sealed system with an unvented hot water cylinder and an immersion backup?
     
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