SiUS331604E Basic ControlFunctions and Control 342.2 Compressor PI ControlCarries out compressor capacity control to maintain Te at constant during cooling operation and Tc at constantduring heating operation thus ensuring stable unit performance.Cooling operationControls compressor capacity to achieve target Te value (TeS).Te: Low pressure equivalent saturation temperatureTeS: Target temperature of Te (Varies depending on Te setting, operating frequency, etc.)(1) VRT control (Default)When the required capacity of all indoor units (suction air temperature – set temperature) is small, the targetevaporation temperature is further increased in order to adjust capacity. From the outdoor unit side, thetemperature difference for all indoor units (∆T) is confirmed, and the target temperature is changed.(2) Constant pressure controlThe target evaporation temperature is not changed.Heating operationControls compressor capacity to achieve target Tc value (TcS).Tc: High pressure equivalent saturation temperatureTcS: Target temperature of Tc (Varies depending on Tc setting, operating frequency, etc.)(1) VRT control (Default)When the required capacity of all indoor units (set temperature – suction air temperature) is small, the targetcondensation temperature is further decreased in order to adjust capacity. From the outdoor unit side, thetemperature difference for all indoor units (∆T) is confirmed, and the target temperature is changed.(2) Constant pressure controlThe target condensation temperature is not changed.Te setting (Make this setting while in setting mode 2.)Lower Normal VRT(Default) Higher3°C(37.4°F) 6°C(42.8°F) Variable 8°C(46.4°F) 9°C(48.2°F) 10°C(50°F) 11°C(51.8°F)Tc setting (Make this setting while in setting mode 2.)VRT(Default) Normal HigherVariable 46°C(114.8°F) 52°C(125.6°F)
