There are many reasons why the components of closed circulating water systems fail prematurely. This is sometimes due to the selection of the wrong material for the application, or a poor quality material. However, probably the most common causes for pmmature failure iu a piping system am the effects of corrosion and deposition. Corrosion is normally linked to poor control of the environment, which can be due to inadequate maintenance procedures or improper initial design. Keywords: closed systems, corrosion control, design solutions, chemical cleaning, chemical treatment, deposits, materials selection, inhibitor, HVAC, maintenance