GREE Air-ccoled Closed Control Unit Service Manual 
 
88
Ⅲ Maintenance 
1. Malfunction List 
Malfunction Signal Source  Control logic  
Power Error 
Phase reversal 
protector 
When phase sequence has malfunction for continuous 
3 seconds, the complete unit will stop and all loads will 
be turned off (without restriction of set delay time). The 
corresponding error code will be displayed on display 
and alarm will be given out. Reset or de-energize the 
unit to clear the error code. 
Alarm of 
overheating 
of return air 
Probe of temp and 
humidity of return 
air 
In auto mode, when indoor fan of each module has 
operated for over 15 min.(3 seconds for quick test), and 
return air temperature is higher than the upper limit for 
continuous 30 seconds, the corresponding malfunction 
code will be displayed on display and also the alarm will 
be given out. The unit will keep running.  Reset the unit 
or detect that such signal has disappeared for 3 minutes 
(3 seconds for quick test), the malfunction code will be 
removed.    If the unit stops for other malfunction during 
this course, the unit makes a judgment again.   
Alarm of low 
temperature 
of return air 
Probe of temp and 
humidity of return 
air 
In auto mode, when indoor fan of each module has 
operated for over 15 min.(3 seconds for quick test), and 
return air temperature is higher than the lower limit for 
continuous 30 seconds, the unit will treat the 
malfunction as same as the malfunction of overheating 
of return air. (If a module has malfunction of probe of 
return air, the detection of the overheating of return air 
will be shielded). 
Alarm of 
high 
humidity of 
return air 
Probe of temp and 
humidity of return 
air 
In auto mode, when indoor fan of each module has 
operated for over 15 min. (3 seconds for quick test), and 
return air humidity is higher than the upper limit for 
continuous 30 seconds, the unit will treat the 
malfunction as same as the malfunction of overheating 
of return air. (If a module has malfunction of probe of 
return air, the detection of the overheating of return air 
will be shielded). 
Alarm of low 
humidity of 
return air 
Probe of temp and 
humidity of return 
air 
In auto mode, when indoor fan of each module has 
operated for over 15 min.(3 seconds for quick test), and 
return air humidity is higher than the lower limit for 
continuous 30 seconds, the unit will treat the 
malfunction as same as the malfunction of overheating