Main Functions SiUS04-70222 Function and Control1.3 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 trouble shooting for fan motor on page 126.Phase Steps Phase control and fan speed control contains 9 steps: LLL, LL, SL, L, ML, M, MH, H and HH.In automatic operation, the step “SL” is not available.= Within this range the airflow rate is automatically controlled when the FAN setting buttonis set to automatic.Note: 1. During powerful operation, fan operate H tap + 50 - 90 rpm.2. Fan stops during defrost operation.Automatic AirFlow Control forHeatingOn heating mode, the indoor fan speed will be regulated according to the indoor heat exchangertemperature and the difference between the room temperature and the required set point.Automatic AirFlow Control forCoolingThe following drawing explains the principle of fan speed control for cooling:Step Cooling HeatingLLL (Heating thermostat OFF)LL (Cooling thermostat OFF)LMLMMHHHH (Powerful)(R4085) (R4085)+∆2.7˚F+∆0.9˚F+∆3.6˚F+∆1.8˚FMMLLfan speedDifference between roomand set temperaturePhase controlThermostatsettingtemperature (R4146)
