In compressors with water jackets and in water-cooled condensers, cooling-water circuits may be in series or parallel. The use of parallel circuits results in a lower pressure drop through the circuit, and may be necessary when the temperature of the cooling water is such that the water temperature rise must be held to a minimum. Figure 8-5 and Figure 8-6 show how to install water lines for series or parallel flow.
Because of occasional damage to condensers by excessive water velocities, it has been found that the water velocity should not exceed 7 feet per second. Thus, to maintain water velocities at acceptable levels, parallel circuiting of the condenser may be necessary. When a water-circulating pump is used, it should be installed so that the condenser is fed from the discharge side of the pump. If the pump is installed on the discharge side of the condenser, the condenser will have a slight vacuum in the water system and the water will be much nearer the boiling point.