Use and Care Manual
Table Of Contents
- Foreword
 - Safety Notice
 - CONTENTS
 - Safety Notice on Maintenance
 - Safety Notice on Operation
 - 1 Product Introduction
 - NOTE: 1 Ton =12000Btu/h = 3.517kW 1.2 Electrical Parameters
 - 2 Control
 - 3 Troubleshooting
- 3.1 Wiring Diagrams
 - 3.2 PCB Layout
 - 3.3 Error Code
 - 3.4 Troubleshooting
- 3.4.1 “E1” Compressor High Pressure Protection
 - 3.4.2 “E3” Compressor Low-pressure Protection, Refrigerant Shortage Protection, Refrigerant Recovery Mode
 - 3.4.3 “E4” Compressor Air Discharge High-temperature Protection
 - 3.4.4 “F2” Condenser Temperature Sensor Error
 - 3.4.5 “F3” Outdoor Ambient Temperature Sensor Error
 - 3.4.6 “F4” Discharge Temperature Sensor Error
 - 3.4.7 “F6” ODU Tube Temperature Sensor Error
 - 3.4.8“EE” ODU Memory Chip Error
 - 3.4.9 “H4” Overload
 - 3.4.10 “H5” IPM Protection
 - 3.4.11 “H6” DC Fan Error
 - 3.4.12 “H7” Driver Out-of-Step Protection
 - 3.4.13 “HC” PFC Protection
 - 3.4.14 “Lc” Startup Failure
 - 3.4.15 “P0” Driver Reset Protection
 - 3.4.16 “P5” Over-Current Protection
 - 3.4.17 “P6” Master Control and Driver Communication Error
 - 3.4.18 “P7” Driver Module Sensor Error
 - 3.4.19 “P8” Driver Module High Temperature Protection
 - 3.4.20 “PA” AC Current Protection
 - 3.4.21 “Pc” Driver Current Error
 - 3.4.22 “PL” Bus Low-Voltage Protection
 - 3.4.23 “PH” Bus High-Voltage Protection
 - 3.4.24 “PU” Charge Loop Error
 - 3.4.25 “ee” Drive Memory Chip Error
 
 - 3.5 Failures Not Caused by Errors
 
 - 4 Maintenance
 - Appendices
 - 1 Resistance/Temperature Lists of Temperature Sensors
- 1.1 Voltage List of 15 KΩ Temperature Sensors (including ODU temperature sensors)
 - 1.2 Voltage List of 20 KΩ Pipeline Temperature Sensors (including temperature sensors for defroster, IDU and ODU pipes)
 - 1.3 Voltage List of 50 KΩ Discharge Temperature Sensors (including discharge air temperature sensor)
 
 - 2 Temperature/Pressure List of Refrigerant
 - 3 Operation Tools
 
MRCOOL DC INVERTER COOLING ONLY CONDENSING UNIT 
62 
4.5 Removal of Major Components 
4.5.1 Removal of ODU Major Components 
Picture 
Name 
Function 
Compressor 
Through compression, the low pressure refrigerant occupies a less space. 
As its pressure and temperature both rise, it becomes high pressure and 
high temperature refrigerant. It is the power drive of the system.   
Motor 
The  power  drive  of  the  fan.  It  enables  the  fan  to  run  so  as  to  provide 
smooth  currents  of  air  for  forced  convection  and  heat  exchange  of 
condenser and evaporator. 
Fan 
It is used to provide smooth currents of air for forced convection and heat 
exchange of condenser and evaporator. 
Gas liquid 
separator 
Installed at the suction side of compressor, it can separate the liquefied 
refrigerant from the gaseous refrigerant to make sure that only gaseous 
refrigerant will be sucked into the compressor. If liquefied refrigerant gets 
inside  the  compressor,  ineffective  compressor  or  slugging  phenomenon 
will occur.   
Condenser 
It is used to transfer partial heat of the hot flow to the cold flow so that the 
flow temperature can reach the specified index. It is an energy exchanging 
device. 










