To prevent what adverse condition should the pH of water in the cooling system be kept above 7?

Maintaining the pH of water in the cooling system above 7 is essential to prevent corrosion. Corrosion occurs when metal surfaces interact with water that is acidic, which can lead to the deterioration of pipes, fittings, and other components over time. An acidic environment can significantly increase the electrochemical reactions that cause metals, particularly iron and steel, to rust and degrade more rapidly.

When the pH is kept neutral or alkaline (above 7), it helps to form a protective oxide layer on metal surfaces, which can significantly reduce the rate of corrosion. This layer acts as a barrier between the metal and corrosive agents present in the water, thus prolonging the lifespan of the system and enhancing the efficiency of heat exchange.

In contrast, scaling may occur due to high mineral content, algae growth is linked to organic matter and nutrient presence rather than pH, and fouling is generally associated with particulate accumulation but not necessarily dependent on pH levels alone. Therefore, understanding and managing the pH level in a cooling system is crucial for preventing corrosion and ensuring efficient operation.