SiBE12-713 Control SpecificationFunction and Control 913.10 Defrost ControlOutline Heat Pump OnlyDefrosting is carried out by the cooling cycle (reverse cycle). The defrosting time or outdoorheat exchanger temperature must be more than its fixed value when finishing.Detail Conditions for Starting DefrostUnder the conditions that the system is in heating operation, 6 minutes after the compressor isstarted and more than 38 minutes of accumulated time pass since the start of the operation orending the defrosting.When the outdoor air temperature and the outdoor heat exchanger temperature meet thefollowing condition for 60 seconds, the defrost control starts.A< –(19/256)×B+(45/64)×CA: outdoor heat exchanger temperatureB: output frequencyC: outdoor air temperatureConditions for Canceling DefrostThe target heat exchanger temperature as the canceling condition is selected in the range of4°C≤Te≤12°C according to the air temperature as the following formula.The target heat exchanger temperature = –(45/64)×(ambient temperature)+14The defrost operation surely operates in 120 seconds after the start. (A→B)After then the defrost operation stops at the following conditions.1. When the heat exchanger temperature reaches the target heat exchanger temperature.(B→C)2. When 650 seconds have passed after the start even if the heat exchanger temperature doesnot reaches the target heat exchanger temperature. (C)A B C(R6959)45 5445 82 PI controlPulse PulsePulse PulsePulse
