Central Heating Systems

From April 2005 all installations have to be condensing, with very few exceptions.

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Back Boilers

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This was a very common way of providing heating and hot water.

With a boiler being situated behind a gas fire and using the existing chimney as part of the flue.

Using just gravity to heat the water and a circulation pump to heat the radiators Probably one of the most reliable boilers, however, not very efficient!

Not the quickest way of providing heating and hot water but these boilers generally last for over 20 years.

Conventional Boilers

A boiler normally mounted on the wall working very much the same as a back boiler.

These boilers can be mounted either on the floor or the wall and work in a similar way to the Back Boiler.

However, in newer installations a valve was used to mean that you could use your heating and hot water independently.

Newer installations would incorporate what is called either a ‘Diverter’ or ‘Mid Position’ Valve. The reason for this is to ensure that you can independently control the hot water and central heating. This valve controls the demand for heat to prevent you from  wasting fuel.

Still extremely reliable but if you require regular amounts of hot water not the best choice as once the cylinder is empty you have to wait for it to heat up again. (In older tanks about an hour but new ones approximately 25 minutes).

Extremely reliable but if you require endless amounts of hot water this may not be the best option for you. The regulations now state that the Cylinder must heat up from cold within 25 minutes although this is not the case with much older systems

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Combination (Combi) Boilers

Just like its name these boilers combine heating and hot water all in one. No tanks and instantaneous hot water.

This type of boiler will provide bath after bath full of hot water but it is important to remember that in the summer when your heating is off there may be a short delay in getting hot water to a tap as the boiler has to heat up before the water can.

Early Combi boilers were not very reliable but as with everything the newer one are very good.

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This type of heating is rarely installed now as the efficiency and performance is not as good as a wet central heating system.

The principal behind it is that cool air is drawn into the appliance and then heated and blown out with a fan.

They normally have a separate appliance within them to heat hot water with a similar method to a back boiler.

It is important that the size of boiler and radiators are correct for the job they are doing.

There are specific methods for calculating this. It is not okay to just add on a radiator if you add an extension as the boiler may not be “man” enough to cope with the extra output required.

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