The Load unit maintains a desired water temperature at boiler (fire) inlet by means of a load valve. It prevents low-temperature corrosion and boiler clogging. It consists of a Grundfos UPM3 25-70 pump, ball shutoff valve for a pump, thermometer, TSV3 load valve and insulation. The TSV3 valve features no automatic bypass closing, so it is necessary to fit a balancing valve at the inlet to port B. Available with opening temperatures either 65°C or 72°C. For boiler of up to 25 kW output.