3. Electric control functions 
3.1 For indoor unit
1. Communication control 
1.1 Remote receive function, with remote controller YR-H71. 
1.2 Long-distance communication, the long-distance control function is pre-setted. 
1.3 Wired controller communication, the wired controller can be used for communication by dip-switch 
selection. The display board is not available when use wired controller. 
Select one control type between wired and remote control, long-distance control can be used with 
wire/remote control. 
2. Function description 
2.1 The running mode includes AUTO, COOL, DRY, FAN and HEAT; can set the compulsory cooling 
function; AUTO/HIGH/LOW 3-speed for indoor motor; can set the TIMER ON,TIMER OFF, TIMER 
ON/OFF and SLEEP function; auto-check water level and control the water drainage of water pump; the 
swing is controlled by stepping motor; 3-minute protection for compressor; anti-overload protection, 
anti-freezed protection, temperature cutoff protection and bad-sensor protection; communication failure 
detect function; check indoor ambient temperature and indoor coil temperature; can be controlled by 
central controller. 
2.2 LED indication: when the unit is switched on by the controller, the POWER LED will be ON, when 
being switched off, the POWER LED will be OFF. When the compressor is running, the compressor LED 
will be on; when it stops, this LED will be off. If the controller is in TIMER and SLEEP mode, the TIMER 
LED will be on; if it is not in TIMER and SLEEP mode, the TIMER LED will be off. 
2.3 Temperature compensation 4℃ control: select by the dip switch on indoor PCB. 
2.4 There is set temperature in AUTO mode as default. 
2.5 Tr stands for room temperature; Ts stands for set temperature; Tg stands for indoor coil temperature; 
Tc stands for defrosting temperature; t stands for compensation temperature; Δ T stands for 
temperature difference. 
2.6  ΔT=Tr-Ts+t (t=0 in cooling mode). 
2.7  ΔT=Ts-Tr+t (t=compensation value, with compensation in heating mode; t=0, without compensation 
in heating mode). 
3. Mode control 
3.1 Indoor AUTO FAN control 
3.1.1 If the unit enters AUTO FAN for the first time, when  ΔT>2, select high speed; whenΔT≤0, select 
low speed; or it will select med speed; when thermostat is OFF, fan will be low speed. (the conversion 
temperature difference is 1 degree). 
3.1.2 If the present fan speed is AUTO HIGH, whenΔT<2, fan speed will change to AUTO MED. 
3.1.3 If the present fan speed is AUTO MED, whenΔT<0, fan speed will change to AUTO LOW; when
ΔT>3, fan speed will change to AUTO HIGH. 
3.1.4 If the present fan speed is AUTO LOW, whenΔT>1, fan speed will chenge to AUTO MED. 
3.1.5 Fan speed conversion in AUTO FAN mode: the conversion will delay for 3 minutes from HIGH to 
LOW, and no delay from LOW to HIGH. 
3.1.6 When the fan speed is HIGH/LOW/MED, on the condition that the protection does not act, the unit 
will run at the set fan speed; when the protection acts, for the sake of the normal operation, the fan 
speed will be forced to conversion; in Dry mode, fan motor will be changed as request. 
3.2 AUTO mode control 
3.2.1 When entering AUTO for the first time, the unit will select the running mode due to the below 
conditions, then perform the selected mode. 
Tr≥Ts-3℃    select COOL mode (includes FAN mode) 
Electric control functions