Tekmar 260 Boiler Control One Stage Boiler & DHW The Boiler Control 260 is designed to operate a single boiler using Outdoor Temperature Reset. It can be used in applications ranging from baseboard or fancoils, to combination space heating and domestic hot water heating installations. This control regulates a single heating water temperature through Outdoor Temperature Reset and/or Domestic Hot Water control. It is capable of controlling a single on/off boiler and can receive both space heating and/or DHW heat demands.