Why is the coil in my evaporative cooling system starting to indicate signs of scaling and corrosion, and the sump showing signs of sludge buildup?
In evaporative cooling equipment, the heat rejection is accomplished by evaporation of a portion of the water being circulated through the fluid cooler. As this water evaporates, the impurities originally introduced with the makeup water remain in the circulating water. To prevent an excessive buildup of impurities in the circulating water, a small amount of water must be “bled” from the system. This is accomplished by the opening the bleed valve located on the discharge side of the spray pump. The bleed rate is approximately 2 GPM per million BTU/Hr of heat rejection.
