GREE                                                                                                    U-Match 5 SERIES UNIT SERVICE MANUAL
 
43 
 
■Ambient temperature of IDU and ODU is too low 
Troubleshooting: 
 
3.4.3  ―E3‖  Compressor  Low-pressure  Protection,  Refrigerant  Shortage 
Protection, Refrigerant Recovery Mode 
Error display: ODU mainboard, IDU wired control and IDU receiver light board will display E3 
Error judgment condition and method: 
It is judged through the action of low pressure switch. If the low pressure switch is cut off, it is judged that low pressure is too low 
and the system stops operation for protection. 
Possible reason: 
■Cut-off valve of ODU is not fully opened; 
■Low pressure sensor is abnormal; 
■Outdoor or indoor fan is not working properly; 
■IDU filter or air duct is blocked (cooling mode); 
■Ambient temperature is too low;