The Difference Setpoint Control 156 is designed to transfer heat from an intermittent heat source to a storage tank. This control can be used in applications ranging from solar thermal to wood boiler systems. Two sensors are used to measure the temperature at the source and at the storage location, and begin heat transfer when there is a positive difference between them. This product uses a single 240 V (ac) rated relay to accomplish this.
The tekmarNet®2 House Control 406 is designed to operate the 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). The heat pump provides either hot or chilled water to a storage tank loop and optional mixed temperature loop. For radiant heating, the water temperature is calculated using Outdoor Temperature Reset. For radiant cooling, the 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. The 406 operates 4 on-board heating and cooling zones and is expandable up to 52 zones on the boiler, tank, and mix water temperatures.