Corrosion
In simple terms, corrosion within heating systems is the result of a chemical reaction between elements within the fill water and different metal components within the system.
This results in the wearing away of the surfaces of those components, leading eventually to perforation and resultant leaks. An important factor in the likelihood of corrosion occurring is conductivity - a measure of a solution’s ability to conduct electricity. The more dissolved salts present in water, the higher its conductivity.
What effect does it have on my system?
The likelihood is that you will encounter problems long before the corrosion is advanced enough to cause leaks. The corrosion process generates iron oxide – a black sludge – which will begin to circulate and eventually settle within your system, blocking pipes, radiators, pumps and heat exchangers, damaging seals and having a detrimental effect on its efficiency and operational lifetime.
In the push towards ever greater efficiency modern heating system components such as valves, sensors and control units utilise very small apertures – the openings through which water flows.
The presence of limescale or rust and sludge, the by-products of corrosion, can block these small apertures very quickly, leading to system failure.
What can I do to prevent corrosion from happening?
The boiler market is a competitive one and manufacturers are seeking to set themselves apart from their competitors by offering increasingly longer guarantees.
They are, however, acutely aware of the impact of poor water quality on components and for this reason many seek to make water control a condition of warranty in order to be able to honour these guarantees.
The VDI 2035 Standard
Many major manufacturers will stipulate the thresholds determined within a European standard for water heating systems. Standard “VDI 2035” is a desired benchmark for the industry, being a series of guidelines set by the Association of German Engineers for the control of water quality for heating water. The UK equivalent would be BS 7593:2019, however the construction industry widely accepts that the VDI 2035 standard is far more exhaustive and scientific than the brief coverage to the subject given by BS 7593.
