Tekmar tN4 Setpoint Control - 1 stage heat. tekmarNet??4 Setpoint Control 161 is designed to operate a single piece of heating equipment in order to maintain a setpoint 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 product regulates a constant water temperature for heating using one of 4 preset modes (setpoint on/off, hot tub, DHW tank, floor PWM). It is capable of operating a single relay (rated at 24 V, 2 A) to control a single device such as a boiler, pump, or valve.