The KTRRB-117.169 air conditioning controller was specially developed to control EC fan coil units, EC fan coil units and other EC fan-assisted air conditioning systems in 2- or 4-pipe systems with normally closed valves. The KTRRB-117.169 is used here as an individual room temperature controller with an internal sensor or as an external control unit with an optional remote sensor. The optional external flow sensor is used to automatically switch the controller to heating or cooling mode in 2-pipe operation depending on the flow temperature; alternatively, this input can be used as an H/C changeover contact. 3-stage fan output 0-10 V with adjustment of the individual fan stages or dynamic 0-10 V for controlling EC fans. Fan operation in neutral zone ON/OFF selectable. In the event of a sensor break or sensor short circuit, the heating is activated with a duty cycle of 30 % to prevent cooling or frost damage in the room. An internal switch can be used to configure the existing contact input as an ECO contact or standby contact. ECO function: If this function is selected, the temperature is set to 3 K lower in heating mode and 3 K higher in cooling mode. Standby function: If this function is selected, the controller is switched off (frost protection remains active). Surface/wall mounting or by means of adapter plate on flush-mounted box.