SiBE041102_A Control SpecificationFunction and Control 253.3 Controls at Mode Changing / Start-up3.3.1 Preheating OperationOutline The inverter operation in open phase starts with the conditions of the preheating command fromthe indoor unit, the outdoor temperature, and the discharge pipe temperature.Detail Outdoor temperature ≥ 7°C → Control AOutdoor temperature < 7°C → Control BControl A ON conditionDischarge pipe temperature < 10°C OFF conditionDischarge pipe temperature > 12°CRadiation fin temperature ≥ 90°CControl B ON conditionDischarge pipe temperature < 20°C OFF conditionDischarge pipe temperature > 22°CRadiation fin temperature ≥ 90°C3.3.2 Four Way Valve SwitchingOutline In heating operation, current is conducted, and in cooling and defrosting, current is notconducted. In order to eliminate the switching sound as the four way valve coil switches fromON to OFF when the heating is stopped, the OFF delay switch of the four way valve is carriedout after the operation stopped.Detail OFF delay switch of four way valve:The four way valve coil is energized for 160 seconds after the operation is stopped.3.3.3 Four Way Valve Operation CompensationOutline At the beginning of the operation as the four way valve is switched, the pressure difference toactivate the four way valve is acquired by having output frequency which is more than a certainfixed frequency, for a certain fixed time.Detail Starting Conditions1. When starting compressor for heating2. When the operation mode changes from heating to cooling3. When starting compressor for defrosting4. When starting compressor for heating after defrosting5. When starting compressor for the first time after resetting with the power ON6. When starting compressor after the fault of switching over cooling / heatingThe lower limit of frequency keeps A Hz for B seconds with any conditions 1 through 6 above.3.3.4 3-minute StandbyTurning on the compressor is prohibited for 3 minutes after turning it off.(Except when defrosting.)A (Hz) 62B (seconds) 50
