Open vent boilers work in a traditional manner, whereby the heating circuit is pressurised using a high level cold water tank usually located in the loft. The open vented boilers, whilst being very traditional in the plumbing arrangement, are however usually wall-hung boilers which help to save large amounts of space.

Typically heat is recovered from the flue gases; the water vapour in the exhausts gases is cooled by the incoming air, thus causing the vapour to form into a liquid state, hence the term condensing. Condensing boilers tend to work at their highest efficiency at lower temperatures so boilers are often designed to feature fully modulating operation at low temperatures, ensuring the output matches very closely to the heat demand.

Most natural gas boilers are suitable for Propane LPG fuel options and require only a change of burner nozzle. Many boilers are now able to run in conjunction with solar panels where gas forms the secondary top up, heat source. Solar smart combi boilers are now being produced by many boiler manufacturers. Other new features available are economisers, or top box gas savers, where even more heat is recovered from flue gases by incorporation of a secondary heat exchanger.

In recent years hybrid versions of combination boilers have evolved whereby a small amount of water storage is provided within the casing of the boiler. These are known as storage combination boilers.

Typical output capacities of combination boilers are 24kw, 28kw and 35kw but this varies with each boiler manufacturer. The efficiency of the boiler is reflected by the SEDBUK rating and ideally one should be seeking a SEDBUK, A or B rated boiler.

System boilers have all the benefits of combis but tend to provide a higher output capacity. They work on a sealed system basis and are predominantly for central heating. If domestic water heating or commercial water heating is required then a storage cylinder is provided in the traditional way.

The Construction Centre can put you in contact with the UKs largest number ofHeating and Plumbing suppliers. So if you are looking for example, supplers of Air Conditioning Units, then the Construction Centre should be top of your list.