Tekmar tN2 House Control. tekmarNet?2 House Control 406 is designed to operate equipment in a 2-pipe, single tank, hydronic heating and cooling system. It operates two heat pump stages (water-to-water or air-to-water) with a backup heat source (boiler or electric resistance). heat pump provides eir hot or chilled water to a storage tank loop and optional mixed temperature loop. For radiant heating, water temperature is calculated using Outdoor Temperature Reset. For radiant cooling, chilled water temperature is maintained at an adjustable setpoint, or is adjusted using dew-point reset with a humidity sensor. A backup boiler can provide an Outdoor Temperature Reset water temperature as well as domestic hot water and setpoint water temperatures. 406 operates 4 on-board heating and cooling zones and is expandable up to 52 zones on boiler, tank, and mix water temperatures.