The One Stage Setpoint Control 150 is designed to operate a single component of a heating or cooling system in order to maintain a set temperature. It can be used in applications ranging from heating a swimming pool to maintaining a constant slab temperature in a commercial car wash bay. This control regulates a constant setpoint water temperature for heating or cooling. The 150 is designed to operate a single relay (rated at 240 V, 8 A) to control a single device such as a boiler, pump, or valve.