SiMT041311E Control SpecificationFunction and Control 462.2 Controls at Mode Changing / Start-up2.2.1 Preheating ControlOutline 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.Preheating control is set to OFF by default.Detail Outdoor temperature ≥ 7°COutdoor temperature < 7°C2.2.2 Four Way Valve SwitchingOutline In heating operation, current is conducted, and in cooling and defrost control, 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.Detail OFF delay switch of four way valveThe four way valve coil is energised for 160 seconds after the operation is stopped.2.2.3 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 when the output frequency is higher than a certain fixedfrequency, for a certain fixed time.Detail Starting Conditions1. When the compressor starts and the four way valve switches from OFF to ON2. When the four way valve switches from ON to OFF during operation3. When the compressor starts after resetting4. When the compressor starts after the fault of four way valve switchingThe lower limit of frequency keeps A Hz for B seconds with any conditions 1 through 4 above.10˚CPreheating ONPreheating OFF12˚CDischarge pipe temperature(R5922)20˚CPreheating ONPreheating OFF22˚CDischarge pipe temperature(R5923)Cooling HeatingA (Hz) 46 52B (seconds) 60 60
