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The condition of the fill and system water can have a marked effect on the corrosion potential. Water is a cheap and plentiful medium and is, therefore, the preferred liquid for transporting heat around a heating or cooling system. Water isn't just water and water chemistry is very complex. It can be highly corrosive to steel and other metals if certain values such as dissolved oxygen content, pH and conductivity are unfavourable. There are different methods of achieving the right water chemistry. The water can be either conditioned or chemically treated or both. There are many water treatment chemicals on the market. The most common ones are corrosion inhibitors. Chemical dosing can be beneficial under certain circumstances. However, it should be viewed like medication and only used to fight very specific problems or if the ingress of oxygen e.g. in open systems, cannot be avoided. A properly sealed system does not need any chemical additives to prevent corrosion. If problems occur which are attributable to corrosion or its effects, it is always better to first find out the causes and rectify them before resourcing to chemical dosing. In other words, find the causes and fix them rather than just fighting the symptoms.

Typical water conditioning equipment