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    How does a combi boiler work?

    Combination or combi boilers have become the most popular and commonly sold type of boiler. This is because water is heated on demand when a hot tap is turned on, meaning you don’t need a hot water storage cylinder, which makes them the ideal choice for homes where space is more limited. 

    Like the name suggests, this type of boiler works by combining a water heater and central heating boiler into one single unit. If the thermostat in the room alerts the boiler to fire up because the temperature has dropped below a set point, the boiler will start so that heat can be put into the central heating system. When the set point of the thermostat is reached, the boiler will turn itself down to ensure the heating stays at the correct temperature and prevents energy waste.  

    If someone in the home turns on a hot water tap, heat is sent into the domestic water supply by a valve to continuously provide heat until the tap is turned off. The valve will then go back its standard position of sending heat to the central heating system. Heat can be delivered to either the central heating or the hot water taps, but it can’t do both at the same time.  

    Is a combi boiler the right choice for your home? 

    To work at their best, combi boilers rely on good mains water pressure so they can provide a steady water flow rate, if you have low pressure the hot water will only drip or trickle out. If your mains water pressure is especially low or your property includes multiple bathrooms, an alternative boiler like a system boiler could be a better choice for you.  

    You also need to make sure that the heat output of the boiler is suitable for your usage. Combi boilers output heat in two ways: one for hot water and one for central heating. It takes more heat and effort to create hot water in comparison to heating radiators, so it will typically come down to hot water output when deciding on a boiler.  

    What are the benefits of combi boilers? 

    • Simple to use- the majority of combi boilers have very basic controls. Thanks to the time and temperature controls, you can plan ahead for the heating to come on when you need it, at your preferred temperature, giving you more control, and helping to lower your energy bills. 
    • Everything you need to provide heat to your radiators or hot water to your taps is all inside the boiler case. Therefore, you won’t need to find or make space for a hot water storage cylinder or central heating pump which is perfect for smaller homes who don’t need a big tank taking up a lot of their already limited room. 
    • Due to not needing a tank in the loft or a hot water storage cylinder, an extra perk of a combi boiler is you don’t need as much pipework which will save you time and money when having it installed.  

    Combi boiler FAQs 

    Do you need a separate hot water cylinder? 

    No, because a combi boiler only heats water when you need to use it through your taps or shower, so storing water for later use is not necessary. 

    Can you have a combi boiler if you have LPG? 

    Yes, there are dedicated LPG models of combi boiler on the market so that house that are not on the mains gas grid can access the benefits of an efficient combi boiler without any hassle. 


    Summary 

    We hope you have found this guide into how combi boilers work helpful. If you’re having a problem with your boiler and don’t want to have to pay a lot of money for a new part, National Boiler Spares can help. We provide refurbished boiler spare parts for a wide range of boilers at affordable prices. Contact us today if you need help finding the right boiler parts for your unit.