Control Specification SiBE12-81772 Function and Control3.3 Controls at Mode Changing / Start-up3.3.1 Preheating OperationOutline Operate the inverter in the open phase operation with the conditions including the preheatingcommand from the indoor, the outdoor air temperature and discharge pipe temperature.The power consumption of preheating operation is 35W. (The total power consumption dependson the number of the indoor units.)Detail Preheating ON Condition When outdoor air temperature is below 10.5°C and discharge pipe temperature is below10.5°C, inverter in open phase operation starts.OFF Condition When outdoor air temperature is higher than 12°C or discharge pipe temperature is higherthan 12°C, inverter in open phase operation stops.3.3.2 Four Way Valve SwitchingOutline Heat Pump OnlyDuring the heating operation current must be conducted and during cooling and defrostingcurrent must not be conducted. In order to eliminate the switching sound (as the four way valvecoil switches from ON to OFF) when the heating is stopped, the delay switch of the four wayvalve must be carried out after the operation stopped.Detail The OFF delay of four way valveEnergize the coil for 150 sec after unit operation is stopped.3.3.3 Four Way Valve Operation CompensationOutline Heat Pump OnlyAt the beginning of the operation as the four way valve is switched, acquire the differentialpressure required for activating the four way valve by having output the operating frequency,which is more than a certain fixed frequency, for a certain fixed time.The lower limit frequency is restricted to 48Hz for 70 seconds on both cooling and heating,except under the condition of heating overload (outdoor temperature ≥ 15 degree).Detail Staring Conditions1. When starting compressor for heating.2. When the operating mode changes from the previous time.3. When starting compressor for rushing defrosting or resetting.4. When starting compressor for the first time after the reset with the power is ON.Set the lower limit frequency to 48 (model by model) Hz for 70 seconds with any conditions1 through 4 above.3.3.4 3-Minute StandbyProhibit to turn ON the compressor for 3 minutes after turning it off.(Except when defrosting. (Only for Heat Pump Model).)
