2HUM18HC03/R2(DB)-SM  Wiring diagrams 
19
Domestic air conditioner
5.1.10 Urgent on/off input 
Press the urgency button the buzzer will ring. The system will enter the automatic mode if you 
don’t press the button for more than 5 seconds. 
Under the system off mode, if you press the urgency key for 5 to 10 seconds, the system will start 
the test operation. 
Under the system off mode, If you press the urgency key for 10 to 15 seconds, the display screen 
will show the resume of the last malfunction. 
If the system is under operation, the press on the urgency key will stop it. 
Under the system off mode, the display screen will show automatic running sign. 
Under the system off mode, the system will not receive the remote control signal if the press on 
the urgency key doesn’t last for 15 seconds or if the key is loosened.   
Urgency operation: If you press the urgency key for less than 5 seconds, the buzzer will ring 
when you press the on/off key. The system will enter the urgency operation when the urgency 
key is loosened. The urgency operation is fully automatic. 
Test operation. 
The inlet temperature sensor doesn’t work, the indoor fan and the indoor air direction board 
motor works synchronically. High speed airflow, cooling, outdoor system on, etc, will send the 
ambient temperature 30 centigrade and coil temperature 16 centigrade information to the 
outdoor system. 
Test operation 
The defrost protection of the evaporator doesn’t work. 
The temperature control doesn’t work. 
The test operation will be finished in 30 minutes. 
The test operation can be stopped by the relative commands from the remote control. 
5.1.11 Low load protection control 
In order to prevent the frosting of the indoor heat interaction device, the outdoor system will be 
stopped if the indoor heat interaction temperature is below zero centigrade for 5 minutes, but the 
fan will continue to operate. The outdoor system will be started again when the heat interaction 
temperature is above 7 centigrade and the system has been stopped for 3 minutes. The 
malfunction will be stored in the malfunction resume and will not be revealed. 
5.1.12 High load protection control 
The outdoor system will be stopped if the coil temperature is above 65ć for 2 minutes. The 
indoor fan will be controlled by the thermostat. The outdoor system can be restarted when the 
coil temperature is below 42ć  and the system has been stopped for 3 minutes. The malfunction 
will be stored in the malfunction resume and will not be revealed.