Haier AB122ACERA Service Manual - Page 37

Commercial Air Conditioner Model: AU122AEERA AB122ACERA AC122ACERA AD122ALERA 1.5 Outdoor defrosting control 1.5.1 Enter condition In heating mode, if the compressor has run for 10 minutes continuously and run for 45 minutes in all(clear the compressor accumulative operation time when defrost over or enter cooling mode), the system will measure the defrosting temp. sensor Tcs(check the frosting condition of outdoor heat exchanger) and outdoor ambient temp. sensor Ta, if the below condition can be met for continous 5 minutes, the unit will enter defrosting operation: Tcs≤C×Ta－α Herein: C: Ta＜0℃, C=0.8(E) Ta≥0℃, C=0.6(E) Set α= 8 according to the data of EEPROM. Herein: when C×Ta－α exceed the range of -12℃≤C×Ta－α≤-6℃, If C×Ta－α-6℃, regard it as equal to -6℃. 1.5.2 Defrost interval time When C×Ta－α＞-12℃, compressor defrost accumulative operation time is 45 minutes; When C×Ta－α≤-12℃, compressor defrost accumulative operation time is 45 minutes 1.5.3 Defrost operation when defrost begins, compressor will stops for 1 minute, outdoor fan runs, after 50 seconds, 4-way valve OFF. Outdoor fan stops when compressor starts up, compressor running frequency must be stay at 60Hz (E) for 1 minute, and then rise up to the target frequency 88Hz. Compressor current and discharge protections are valid during defrost, when compressor stops because of protection or failure in defrost mode, resume after stopping for 3 minutes, accumulative operation time will not be cancelled. Enter defrost when the continuous operation time is met. When enter defrost, quit defrost only when 2 minutes of the compressor min. operation time is met. 1.5.4 Quit condition When any of the following condition is met, change defrost to heating mode. (1): Outdoor heat exchanger temp. over 10℃ last for 60 senconds contineously; (2): Outdoor heat exchanger temp. over 14℃ last for 30 senconds contineously; (3): Defrost for 9 minutes contineously. 1.6 PTC output control When outdoor unit is electrified, PTC output is 0, 3 seconds later, it is 1. 1.7 Heater control When compressor stops and outdoor ambient temp. less than 26℃, heater will work, or stop it. 1.8 auto-checking function(pre-set) Auto-checking function: When first short-circuit CJ601 then electrified, enter auto-checking. The process is as following: failure lamp LED001---PTC---4-way valve---heater---high speed---low speed--expansion valve(A-B-C-D)---LED lamp board(LED5-LED4-LED3-LED2-LED1-compulsory cooling-compulsory heating-DC fan motor-inverter fan motor) Compulsory cooling when SW5-2 on LED lamp board is "ON", LED5, LED4, LED3, LED2 and LED1 are all light, or all are black out. Compulsory heating when SW5-1 on LED lamp board is "ON", LED5, LED4, LED3 and LED2 are all light, LED1 is black out, or all are black out. DC fan motor when SW5-4 on LED lamp board is "ON", LED5, LED4, LED3 and LED1 are all light, LED2 is black out. Inverter fan motor when SW5-4 on LED lamp board is "OFF", LED5, LED4 and LED3 are light, LED2