The problems encountered in closed circuit systems are like those in open systems – corrosion, suspended solids, scale, and microbiological contamination.
However, there are differences between the systems which require us to treat them in different ways. The fixed volume, low make-up of a closed system allows us to dose water treatment products at much higher levels than is possible in open systems, where water is constantly lost to drain. Much better corrosion control can therefore be achieved in closed systems. Another factor is that the dissolved oxygen level in a closed system should be low which should reduce corrosion rates. Higher biocide levels and long contact times allow good microbiological control in closed systems to be achieved. Scaling is not generally a problem unless there is substantial make-up.
Sci-Tech has a full range of scale and corrosion inhibitors, pre-commission cleaners, system flush chemicals, and biocides for use in closed circuit heating and chilled systems. This range also contains many specialist products formulated for use in specific specialist or problematic situations.