Modern Building Services

18 MODERN BUILDING SERVICES MAY 2022 FEATURE HEATING This has a direct impact on boiler efficiency and, of course, the problem is proportional to the volume of the system, so larger systems are more greatly affected. To prevent scaling on commercial systems over 600kW, the European standard VDI 2035 recommends the removal of all hardness formers to eliminate limescale deposits through demineralization. For smaller systems, and domestic applications in general, then water softening is a viable alternative to remove primarily the calcium and magnesium via an ion exchanger. Whichever method is used, the conductivity of the water is reduced. As demineralisation can also remove chlorides, this method also helps reduce corrosion. Test results Depending on the results of the water test, recommendations could range from a mechanical solution, such as the fitting or replacement of a pressurisation unit, vacuum degasser (for the elimination of microbubbles and dissolved gases) or a dirt separator, to a chemical ‘dosing’ solution or a demineralisation solution. Another good reason for carrying out a water quality test is that many HVAC manufacturers will only offer a warranty if the system water meets certain standards. In the UK the standard is BG 29/2020, as promoted by BSRIA (the Building Services Research and Information Association). According to the standard the system fluid should be compliant to: • A pH value (measuring water acidity) of between 8.2 and 9.5 • Hardness 0 °dH (degree of hardness) • Electrical conductivity (the ability of water to pass electricity) no higher than 100 µS • Minimal microbiological activity This requirement is in place to avoid scaling and corrosion, and which is a key issue where there is high conductivity in water. The more ions present in water the faster the rate of corrosion. When this occurs, the plantroom equipment becomes less efficient and increases the fuel consumption of the system. Ignoring the BG 29/2020 guidelines is likely to increase the system’s dependence on continuous dosing; but this would mean the symptom was being treated as opposed to the cause. So, in summary, awater quality test could be the key to unlocking the ‘dirty secrets’ of an inefficient heating systemand opening the door to better water qualitymanagement, the benefits of which are: • Reduced corrosion of metals within the system • Scale formation is inhibited • Primary plant equipment is protected • Lower maintenance • The opportunity for microbiological organisms to grow is lessened • Increased system lifespan and efficiency. CPD and solutions guide To further support estate managers, specifiers and M&E contractors, Spirotech has launched a new CPD ‘ UnderstandingWater Quality & Total Solutions’ . Presented by a member of our technical team, it looks at common problems caused by poor water quality, from balancing issues and pump inefficiency to kettling and poor circulation. Other topics include hydronic stability, the latest regulations and guidelines, how water conductivity causes corrosion, and the impact of hard and soft water. Bacterial contamination is also covered. We have also created a 16-page ‘problem solving’ guide, ‘Best in Class Heating’ , which explores the issues that can arise in heating systems, whether it is a refurbishment or a new-build. More information can be found at www.spirotech.com “Another good reason for carrying out a water quality test is that many HVAC manufacturers will only offer a warranty if the system water meets certain standards.”