Si12-308 Main FunctionsFunction and Control 771.3 Fan Speed Control for Indoor UnitsControl Mode The airflow rate can be automatically controlled depending on the difference between the settemperature and the room temperature. This is done through phase control and hall IC control.For more information about hall IC, refer to the troubleshooting for fan motor on page 176.Phase Steps Phase control and fan speed control contains 9 steps: LLL, LL, SL, L, ML, M, MH, H and HH.= Within this range the airflow rate is automatically controlled when the FAN settingbutton is set to automatic.Note: 1. During powerful operation, fan operates H tap + 50 - 90 rpm.2. Fan stops during defrost operation.Automatic AirFlow Control forHeatingThe following drawing explains the principle for fan speed control for heating:Automatic AirFlow Control forCoolingThe following drawing explains the principle of fan speed control for cooling:Step Cooling Heating Dry modeLLL (Heating thermostat OFF)25 · 35kW class :500 - 860 rpm(During powerful operation :850 - 910 rpm)50 · 60 · 71kW class :750 - 1000 rpm(During powerful operation :1050 rpm)LL (Cooling thermostat OFF)SL (Silent)LMLMMHHHH (Powerful)(R2818) (R2818)-1.5˚C-0.5˚C-1˚C-2˚CLMLMThermostatsettingtemperaturePhase controlDifference between roomand set temperaturefan speed (R2819)+1.5˚C+0.5˚C+2˚C+1˚CMMLLfan speedDifference between roomand set temperaturePhase controlThermostatsettingtemperature (R2820)
