Haier 1U71S2SG1FA Service Manual

Also see for 1U71S2SG1FA: Installation manual Service manual Installation manual

Contents

221Send oil return signal oil return begins oil return over60s ref. eliminated 30sOil return frequency auto frequencyLow frequencyInverter compressor auto frequency350pulse(E)running indoor PMV auto angle auto angle120pulse(E)80(E)stopped indoor PMV OFF angle 5(E) OFF angle 5(E)Outdoor motor AUTO AUTO (TC or ambient temp. control) AUTOrunning indoor motor AUTO AUTO (set fan speed) AUTOstopped indoor motor STOP STOP STOP4-way valve OFF OFF OFFMulti:D: Entering conditionWhen the compressor running frequency is lower than 58Hz (E) continuously for 4 hrs, the system will enter oilreturn operation. In the course of mode changeover, manual unit stop or protective unit stop, the time will beaccumulative. After the compressor restarts up, the time will be counted continuously. In a continuous 4 hrs, if thecompressor running frequency is not less than 72Hz for over 10 minutes continuously, the accumulative time will becleared. Also after the heating defrosting, the time will be cleared.E: ProcedureCooling mode: refer to “the oil return procedure in cooling mode”Heating mode: refer to “the oil return procedure in heating mode”F: The protection treatment in oil return operationIn the course of oil return, because of protection or abnormal unit stop, after the unit restarts up, the time will not becleared, the system will need another oil return operation. In the refrigerant flow course in the oil return of coolingmode or after the oil return, and within 5 minutes after the refrigerant being eliminated is over, the anti-freezedprotection is invalid, and also the low voltage protection is invalid. But the other protection is valid.In the course of oil return from heating mode to cooling mode, if abnormal condition occurs or the unit stops forprotection, then the system needs not another oil return within 3 minutes after the unit stops and it will start updirectly, then to heating mode.In the course of oil return from heating mode to cooling mode, the anti-freezed protection is null and void, and thelow voltage protection is null either. The other protection is valid.Oil return procedure in cooling mode: