Haier HBU-18HF03 Manual page 231

Electric control functions
Tr＜Ts-3℃ select HEAT or FAN mode
3.2.2 After entering the AUTO mode, the mode can change over among COOL, HEAT or FAN modes
according to the indoor ambient temperature (conversion temperature difference is ±3℃).
3.2.3 If the unit is in COOL mode, when it arrives compressor-stop temperature, the compressor will stop;
after compressor stops for 15 minutes, the unit will check the room temperature, if Tr＜Ts-3℃, the unit
will enter HEAT or FAN mode, or the unit will still be in COOL mode;
3.2.4 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.
3.2.5 For cooling only unit, if the unit is at FAN mode, if Tr＞Ts+3℃, the unit will enter COOL mode.
3.2.6 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.
3.3 COOL mode control
3.3.1 4-way valve being powered off, compressor run/stop will depends on the temperature difference
between the room temperature at present and the set temperature.
3.3.2 In cooling mode, every time the compressor starts up(thermostat ON), 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.
3.3.3 ΔT≥1 compressor will run;
ΔT≤-1 compressor will stop;
-1<ΔT<1 compressor will stay in original state
3.3.4 Anti-freezed protection (invalid in compulsory operation, trial running, heating mode)
Indoor coil temperature Tg≥15℃, outdoor motor run in compulsory HIGH and resume to normal HIGH
when Tg<13℃. Indoor coil temperature Tg＜5℃, outdoor motor run in compulsory LOW and resume to
normal HIGH when Tg>7℃. Outdoor motor run in normal HIGH when 5 ≤ ℃ Tg＜15℃.
When the unit has run for over 6 minutes after compressor starts up, if indoor coil temperature Tg<1℃
and lasts for 1 minute, the compressor and the outdoor motor will stop, and the unit will change to FAN
mode; 9 minutes later after compressor stops and when indoor coil temperature rises to 10℃, the unit
will resume to COOL mode, the compressor and the outdoor motor will run again.
3.3.5 Temperature cutoff protection
In cooling mode, the unit will check indoor coil temperature every time the compressor start and has run
for 5 minutes, when indoor coil temperature Tg>Tr＋5, the unit will stop and 3 minutes later restart up; if
the temperature cutoff occurs for 3 times continuously, the unit will stop and alarm.
3.4 DRY mode control
3.4.1 When the uint enters DRY mode for the first time, the compressor, outdoor motor and indoor motor
will perform according to the below conditions:
ΔT＞2, the compressor and the outdoor motor will run continuously, indoor motor will run at the set
speed, this area is defined as Area A;
0≤ΔT≤2, the compressor and the outdoor motor will always run for 10 minutes and then stop for 6
minutes, indoor motor will be LOW speed, this area is defined as Area B;
ΔT＜0, the compressor and the outdoor motor will stop, indoor motor will run at Low speed, this area is
defined as Area C.
3.4.2 After the unit is running in DRY mode, the system will change over among Area A, Area B, and
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