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What could I replace this system with?

Discussion in 'Plumbing and Central Heating' started by Sonic007, 29 Aug 2020.

  1. Sonic007

    Sonic007

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    Hi everyone,

    I recently moved into a detached house that is about 20 years old and has the original boiler.
    The boiler is in the kitchen and then upstairs I have a cupboard with a hot water tank.
    There is also a cold water tank in the loft.

    I had the boiler serviced and it works but not operating as efficiently.

    I’d like to look at replacing it and wondered if I could also:

    - Remove the hot water tank so the cupboard can be used.

    - Get rid of the water tank in the loft.

    I’m guessing there is a reason it was setup this way but would like to hear my options available.

    It is a 4 bedroom detached house, two bathrooms and radiators in each room.

    Would a combi boiler not provide enough hot water for a bath for example?

    Thankyou for your advice. It is much appreciated.
     
    Last edited: 29 Aug 2020
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  3. dilalio

    dilalio

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    Combi can be installed with 2 bathrooms but you need to determine how many litres per minute you get from your incoming main and then choose a combi that can make the most of a decent flow rate... Even then, there will be some compromise on the performance of the system, which you will only be able to "feel" once its done.

    It's a case of personal showering/bathing expectations over freeing up space in the property.

    I have 3 showers with 5 adults and teens and we are quite happy to have accepted and adjusted our schedules to get the best shower. But we have a very good flow rate for the main and a combi which gives good hot water delivery.
     
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  4. Sonic007

    Sonic007

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    Thankyou for your reply. That does make sense. Will have to look into my flow rates.
    We have 3 kids that are fast growing up into teens so I think I’m going to need a decent system as they are always running the bath after football and don’t want one to get hot water and then the other two get cold.

    At the moment hot water is pretty constant.
     
  5. bernardgreen

    bernardgreen

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    Check your incoming water supply, ( flow and pressure ) is suitable before committing to a combi

    The maximum heat output rating you need is determined by the hot water requirement ( flow and temperature to hot water taps ) that you need.

    This is typically several times ( worse case as much as 20 times ) the amount of heat needed to keep the house warm.

    For room heating the boiler has to modulate ( reduce ) it's heat output to match the much lower heating requirement.

    There is a minimum heat output that the boiler can modulate down to. After that the boiler has to turn it's flame ON and OFF in cycles to provide the low room heating requirement.

    Cycling a boiler increases the wear and tear and can be inefficient.

    Installing a high power boiler may require a new and larger gas pipe is run from meter to boiler. A route for this may involve it being run along the outside of the house.

    Also with a hot water cylinder you can have an immersion heater to heat the water when the boiler fails.
     
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  6. jacko555

    jacko555

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    Yes, easily enough for a bath to run quickly and hot. Although if running a bath, and someone else showered, you'll get a reduced flow rate.

    My old house was bad for this, running the kitchen hot tap while someone else showered meant you both got a slower stream of water.

    The limit was the water pressure coming into the house.
     
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  7. Jackrae

    Jackrae

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    If saving money is your prime motivator then stick with what you have. Savings on gas purchase will never offset cost of installation
     
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  9. jacko555

    jacko555

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    I agree with this.
    Assuming there's enough of a flow rate, I'd choose a combi over hot water tank.
    This is subjective personal preference.
    I have lived with both and prefer combi
     
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  10. denso13

    denso13

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    Same here, I have a quite a large house with an old 28kw combi and have no complaints.
     
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  11. Sonic007

    Sonic007

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    Thanks for your replies everyone.

    I have a lot to think about. Has anyone used or heard of Combi Storage boilers....from what I understand they are combi boilers but with a bigger storage tank so would hold more hot water?
    I was looking at those and wondered if that would be an option.
     
  12. bernardgreen

    bernardgreen

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    They have a small tank of water inside the boiler.

    When a hot tap is turned ON a "normal" combi boiler has to fire up and get the heat exchanger hot enough to heat the water flowing through the boiler.

    Hence there can be a significant delay ( and water wasted ) before the heat exchanger is hot enough to heat the water leaving the boiler.

    The length of the delay depends on how much metal has to be heated before any heat reaches the water flowing through the boiler to the taps.

    To remove the effect of this delay a tank of water in the boiler is kept hot ( the boiler fires up from time to time to keep it hot ) and this pre-heated water flows to the taps while the heat exchanger is warming up.
     
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  13. denso13

    denso13

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    Could be but would still depend on existing flow rates amongst other things. You need an installer to take a look and advise really.
     
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  14. Sonic007

    Sonic007

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    Thankyou everyone. It is good to know a bit more about it all.
    I will get someone in to assess the flow rates and options available.
     
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