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 
72 
Model: MDUCO18048060
Removal of front panel 
NOTE: Before removing the front panel, make sure power is cut off.
Step 
Picture 
Work instruction 
1. Remove the upper cover
plate.
 Unscrew the screws of the
upper cover plate with a
screwdriver.
2. Remove front side plate
sub-assy.
 Loose the screw fixing the
frontside plate with
screwdriver.
 Hold the front side plate
upwards and then put it on
the floor flatly.
3. Remove front panel and grille.
 Loose the screws fixing the
front panel and grille with
screwdriver.
 Put the front panel and grille
on the floor flatly.










