PLUMBING &
HEATING

A condensing boiler with a gas-to-water or primary heat exchanger, of which there may be more than one, has a larger surface area than it would within a non condensing boiler. This extra surface area allows more heat to be extracted from the combustion process for the same amount of fuel that is consumed in a non condensing boiler. They are available as regular and combi models, floor standing or wall hung. Care is needed when siting the flue terminal, due to the plume effect. They require less fuel to apply the same amount of heat to the system, producing less greenhouse emissions.

Combination Boiler, (often refer to as combi boiler) is a specially designed boiler which is used to heat up the domestic hot water instantly as and when it is required and also to serve a SEALED SYSTEM of hot water central heating. Using this type of boiler reduces the installation costs, in that, no feed and storage vessels are required for the supply of water, also by omitting the storage of domestic hot water a saving can be made in not heating the water unnecessarily..

The temperature of stored hot water should be in the range of 60°c to 65°c and the temperature of distributed hot water should be greater than 50°c. Under normal conditions the temperature of the stored water should never exceed 65°c. A stored water temperature of 60°c is considered sufficient to meet all normal requirements and at this temperature will help prevent microbiological growth.

Water conditioner devices are used to overcome the problems of SCALE in the pipe work. Generally water conditioners do not soften water, they just stabilise the calcium salts which are held in suspension. There are two basic types, those that use chemicals and those that pass water through an electronic or magnetic field. For further information on water conditioners it may be useful to contact The United Kingdom Physical Water Conditioners Association on telephone number: 01484 453667

If you have observed that the hot water temperature has decreased and water flow reduced, especially on a combination boiler chances are that limescale has built up in the domestic hot water heat exchanger. This can be rectified by descaling the heat exchanger using a power flushing machine and a suitable scale reducing device fitted to avoid future re-occurrence.

In a normal, cylinder fed system, the 'cylinder stat' could be set too low. During the winter months, the boiler thermostat may need to be set nearer the maximum than in summer, due to the extra demands made by the central heating.