Wednesday, November 25th, 2015
A combi boiler or ( combination boiler ) is an ingenious space-saving idea and an increasingly popular choice in homes. Combi boilers now account for well over half of all the new domestic boilers installed every year.
A combi boiler is both a high-efficiency water heater and a central heating boiler, combined within one compact unit. Therefore, no separate hot water cylinder is required, offering space saving within the property.
Combination boilers are capable of providing instant hot water and heating while saving space within a home.
The conventional arrangement in Ireland is to have a normal boiler which heats the radiators via a sealed water circuit. By “sealed” it is meant that the water is contained within the system, going around in a loop between the radiators and the boiler.
To heat the “domestic hot water” (i.e. the water that comes out of the hot taps) the storage cylinder in the hot press has a coil in it through which the “radiator water” flows.
The disadvantage of this arrangement is that if the cylinder does not have hot water in it you have to wait some time for the coil to heat it up.
A ‘combi’ boiler is a boiler which combines both a conventional boiler for radiators and an independent water heater, together in the one unit. This dispenses with the hot water cylinder in the hot press. But better still, it means that hot water is always available instantly and for as long as you need it.
Control valves inside combi boilers operate in different directions, either letting the water flow through the central heating system or diverting it to a hot water tap, as required, but never both at the same time.
Combi boilers require sufficient mains water pressure in order to deliver a good water flow rate; low mains water pressure means hot water will merely trickle. If your mains water pressure is low or you have more than one bathroom, a conventional system boiler might be a better option for you.
It is also important to ensure that the heat output of the boiler is correct for your needs. Combi boilers have two heat outputs: one for Domestic Hot Water and the other for Central Heating. More effort and hence more heat is required to produce hot water than to heat a home through the radiators, so it is usually the hot water output that determines your choice of combi boiler.