Series FTS Thermal Flow Switch is especially designed, for all types of cooling systems, as a reliable alternative to failure prone mechanical flow switches. The Thermal Flow Switch continually samples the temperature of the coolant and adjusts the low flow setpoint automatically, providing a solid state switch should the coolant flow rate fall below the setpoint value. In addition, the Thermal Flow Switch will provide an alarm output should the coolant temperature rise above acceptable levels. You have double protection with the FTS.