Special Control SiBE28-80542 Function3.3 Defrosting OperationTo defrost the outdoor unit heat exchanger while in Evaporator, the defrost operation is conducted to recover theheating capacity.[Start conditions]Referring to the set conditions for the following items, start the defrosting operation.• Heat transfer coefficient of the outdoor unit heat exchanger• Heat exchange temperature (Tb)• Timer (Set to two hours at minimum.)Furthermore, the heat transfer coefficient of the outdoor unit Evaporator is computed from Tc, Te, and compressorloads.Outdoor unit actuator Defrost preparationoperation Defrost operation Post Defrost operationCompressor Upper limit control 176 Hz 124 Hz2-steps increase/20sec.till Pc - Pe>0.4 MPaOutdoor unit fan STEP7orSTEP8 OFF STEP8Four way valve ON OFF ONMain motorized valve (EV1) SH control → 480 pls 480 pls 55 plsSubcooling motorized valve (EV2) 0 pls 0 pls 0 plsHot gas bypass valve (SVP) OFF OFF OFFAccumulator oil return valve (SVO) ON ON ONInjection (SVT) (CMSQ200A7 model only) OFF OFF OFFEnding conditions 170 sec. • 10 min.• Tb>11°C • 10 sec.• Pc - Pe>0.4MPaor orIndoor unit actuator During defrostFanThermostat ON unit OFFStopping unit OFFThermostat OFF unit OFFElectronic expansion valveThermostat ON unit Defrost EV opening degreeStopping unit 256 plsThermostat OFF unit Defrost EV opening degree
