Control Specification SiBE07-618_D32 Function and Control3.3 Controls at Mode Changing / Start-up3.3.1 Preheating OperationOutline The inverter operation in open phase starts with the conditions of the outdoor temperature, thedischarge pipe temperature, and the radiation fin temperature (internal temperature of PM1).Detail Outdoor temperature ≥ 10°C → Control A (preheating for normal state)Outdoor temperature < 10°C → Control B (preheating of increased capacity)Control A ON conditionDischarge pipe temperature < 6°CRadiation fin temperature < 85°C OFF conditionDischarge pipe temperature > 8°CRadiation fin temperature ≥ 90°CControl B ON conditionDischarge pipe temperature < 10.5°CRadiation fin temperature < 85°C OFF conditionDischarge pipe temperature > 12°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 when the heating is stopped, as the fourway valve coil switches from ON to OFF, 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 150 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 differential pressure 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 heating.2. When the operation mode changes to cooling from heating.3. When starting compressor for defrosting or resetting.4. When starting compressor for the first time after the reset with the power is ON.5. When starting compressor for heating next to the suspension of defrosting.6. When starting compressor next to the fault of switching over cooling / heating.Set the lower limit frequency A Hz for B seconds with any conditions 1 through 6 above.A (Hz) B (seconds)48 70