Drinking water supplies in Britain are controlled by national and European standards. In normal circumstances there is no need to treat the water, however, water quality varies according to its hardness and softness depending on any geographical region. When passing through any domestic heating or air conditioning system, hard water does deposit limescale that could damage plumbing and appliances. Domestic water treatment chemicals play a necessary role in the maintenance of central heating boilers, especially combination boilers. Particles and other debris in water passing through combi boilers is a common cause of problems and breakdown. This type of boiler is not very tolerant of contaminants.
Equally, the heat exchanger on a boiler can fail because of corrosion. Such corrosion can also occur in other parts of the heating system, such as the radiators. This type of corrosion can be minimised by the introduction of a chemical inhibitor that will protect all of the metals present within the system. These inhibitors will also prevent the build up of lime scale in hard water areas; Chemicals that reduce lime scale build up are usually phosphates that react with metallic ions in the water to keep them in solution. These can be plumbed in directly at the cold water inlet to any appliance; Corrosion inhibitors should be added to a heating system when it has been cleansed thoroughly and finally filled. The product has to be selected on the basis of the system components, as not all chemicals work universally, and the inhibitor level should be checked at least annually. Corrosion inhibitors will also work to reduce the noise in heating systems that is often created by lime scale precipitation; Leak sealers can be added to joints in the piping system, which otherwise would require costly repairs. These are very effective at sealing a small capillary leak by affecting the surface tension of the water.