HVAC Chemical Dosing

It is used to prevent unwanted biological and chemical activity in the utility fluid.

Biological activity takes place in the absence of biocides. Unchecked, micro-organisms naturally present in all waters can grow on heat exchange surfaces, reducing their effectiveness. Over time, blockages can occur, perhaps diverting utility flows in the wrong direction and making equipment unusable. Stripping equipment and cleaning it prior to reassembly will become necessary in the worst cases.

In the absence of biocides, evaporative cooling towers, for example, have no protection against the spread of the bacterium legionella pneumophila, the agent culpable for Legionnaire's Disease.

Chemical dosing is needed to maintain acidity within limits so as to prevent equipment corroding. Also, heat exchange surfaces are susceptible to precipitation of insoluble species such as silica and the calcium and magnesium carbonates and sulphates, among a number of others ("kettle scale" or "kettle fur").

Chemical dosing has a significant economic effect on the operation of all utility networks. In the absence of a local tame plant specialist, the service should be bought-in from well-known suppliers.