Flow switches are used on chilled water lines primarily as what type of switch?

Flow switches installed on chilled water lines serve primarily as safety lockout devices. Their main function is to monitor the flow of water in the system to ensure that it is within acceptable parameters. If the flow drops below a certain level, which could indicate a problem such as a pump failure or a blockage, the flow switch will activate a safety relay or alarm. This action helps in protecting the system from potential damage by preventing operation under unsafe conditions.

Using a flow switch as a safety lockout is crucial because it can prevent issues such as overheating or overpressurization, which could lead to major failures. This highlights the importance of maintaining a proper flow to ensure the system operates efficiently and safely.

Other types of switches, like control switches, are generally used for regulating operations within a system rather than providing a direct safety mechanism. Pressure relief devices are designed to alleviate excessive pressure, while flow measurement devices focus on quantifying the rate of flow, not necessarily on safety. Therefore, the primary role of the flow switch in this context aligns most closely with the function of a safety lockout.