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Combi Boilers

Combi Boilers

All the major heating components are housed in one unit which makes them very convenient to the installer. They are especially suitable for smaller households with undemanding lifestyles. However, they may not be the best choice for larger households.

Water to the hot taps or shower comes out at mains pressure although it has to pass through the boiler slowly for it to be heated sufficiently. The flow rate is therefore limited for a given temperature rise. The high pressure and low flow is perfect for showers. It dispenses with the need for power shower pumps which might be necessary in a conventional system with a low pressure head.

Combis generates hot water as and when it is needed, avoiding running out of it. Standard combis provide maximum pressure through only one tap at a time. If you have two taps running the flow rate diminishes. This can be partly overcome with a high power or a storage combi.

When comparing flow rates of different combis make sure that they are specified for identical temperature rises. They are commonly specified at either 35°C or 30°C rises, the lower the rise the greater the flow. However, the temperature rise required in practice is often a good deal higher than either of these figures.