Haier AB122ACERA Service Manual - Page 43

Commercial Air Conditioner Model: AU122AEERA AB122ACERA AC122ACERA AD122ALERA conditions, then perform the selected mode. Tr≥Ts-3℃ select COOL mode (includes FAN mode) Tr＜Ts-3℃ select HEAT or FAN mode 4.2 After entering the AUTO mode, the mode Temp. rising Temp. falling cooling can change over among COOL, HEAT or FAN modes according to the indoor ambient cooling Ts+3℃ temperature (conversion temperature difference is ±3℃). 4.3 If the unit is in COOL mode, when it arrives compressor-stop temperature, the Ts-3℃ heating/blowing compressor will stop; after compressor stops for 15 minutes, the unit will check the room heating/blowing temperature, if Tr ＜ Ts-3 ℃ , the unit will enter HEAT or FAN mode, or the unit will still be in COOL mode; 4.4 For the heat pump unit, if the unit is in HEAT mode at present, when it arrives compressor-stop temperature, the compressor will stop; after the compressor stops for 15 minutes, the unit will check the room temperature, if Tr＞Ts+3℃, the unit will enter COOL mode, or it will still be in HEAT mode. 4.5 For cooling only unit, if the unit is at FAN mode, if Tr＞Ts+3℃, the unit will enter COOL mode. 4.6 When the unit is in HEAT mode, if indoor heat exchanger temperature rises up to over 63℃, the unit will change into COOL mode. And within 1 hour, the heat exchanger temperature will not be limited, the heating operation will stop temporarily. 1 hour later, the unit will select the proper mode due to the above condition. 5. COOL mode control 5.1 4-way valve being powered off, compressor run/stop will depends on the temperature difference between the room temperature and the set temperature. 5.2 In cooling mode, every time the compressor starts up, within 6 minutes, the compressor will not be limited by the temperature sensor, but the set temperature change, shutoff signal and protection action will not be limited by 6-minute protection, and the compressor can stop immediately. 5.3 ΔT≥1 compressor will run; run ΔT≤-1 compressor will stop; -1