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What is a Combi Boiler?

With there ever increasing popularity "What is a combi boiler" is becoming a very popular question that we get at Boilers Ireland. With a big clue being in the name "combi" short for combination, its the term used to describe a combination boiler. Combination boilers heat your radiators and also separately the hot water used for showering from the same unit.

One of the key advantages of this boiler is that there is no need for a separate hot water heater (ie) you will not have an immersion heater in the hot press. Which results in a large amount of space saving in the home? Your only heating the hot water that you need, no more" HAVE I LEFT THE IMMERSION on moments?"

What water does it use?

A combination Boiler works by taking water directly from the pumped cold supply. Other installers take the water supply to the Boiler from the mains water supply of the house but we have found that due to the unreliability of the water pressure from Irish Water that the installation of a water pump and connection to a cold supply of your tank in the attic is the best way to achieve optimum Boiler performance and giving our clients great water pressure at all appliances regardless of the mains supply pressure.

How does it work?

When you open up a hot tap in your home, the pump kicks in with a powerful supply of water to the Boiler, which then turns on the Gas burner and heats the water through a heat exchanger located inside the boiler. This all happens in the blink of an eye and nearly instantaneously heats the water.

To deliver even better performance, modern Combi's have a "pre-heat function". That means that a small pre-heated reservoir of hot water is kept inside the boiler, ready to be used as soon as somebody opens a tap or a shower calling for heat. This function is used to insure that hot water is delivered as fast as possible when called for. The "pre-heat function" can also be disabled if required.

The water for your radiators is totally separate and doesn't mix with your shower water. The heating works of a timeclock and thermostats that you would have programmed to your desired time and temperature.

Can I change over from an unconventional boiler?

Yes you can, its actually an area that the team at Boilers Ireland specializes in. A combi boiler conversion is something that can be achieved in most settings with some alterations to the current system. The cost savings and space savings as can be seen in the pictures contained within this blog can be quite substantial.

If you need any further information or advice, why not get in touch with us at BoilersIreland and we would be delighted to help you out.

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1 Comment

Unknown member
Apr 20, 2022
Good morning, my name is Ruben from, I am writing to you from Spain, where we have a company specialized in boilers and air conditioning, we are following blogs from all over the world in our sector that we find interesting, such as yours. First of all, I'm sorry if my English is not quite correct. We are contacting companies from all over the world to ask them about the aerothermal systems that are currently starting to work in our country, and we would like to know if it is a system used in your country and what is your opinion about it. Thank you very much in advance for your answer. Kind regards Ruben
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