MrCool DIY E Star Series Installation & Owner's Manual page 56

10.11 Error Code: PC 03 (Low pressure protection diagnosis and solution)
Description: Outdoor pressure switch cut off the system because pressure has become lower than 0.13 MPa.
If this occurs, the LED will display the failure code.
Recommended parts to prepare:
• Connection wires
• Outdoor PCB
• Low pressure protector
• Refrigerant
Troubleshooting and repair:
Low pressure protection
Are the low pressure protector
and main control board wired
Is the low pressure
protector broken?
Test method: Disconnect the plug.
Measure the resistance of the
low pressure protector. If the
protector is normal the value will be 0.
Does a problem still exist?
Is the outdoor ambient
temperature too low?
Is the valve core of the high
pressure valve fully opened?
Is the indoor fan running properly
in cooling mode?
Replace the outdoor main board.
Does a problem still exist?
When the level of refrigerant is
not sufficient, does the system
function properly after more
refrigerant is added?
Check the refrigerant system and
ensure it is functioning properly.
The error codes and descriptions are for reference only. If your system displays any of
these codes contact a qualified technician to investigate the matter further.
Page 55
NO
properly?
YES
YES
YES
NO
NO
YES
NO
YES
NO
NO
****Disclaimer****
mrcool.com
Reconnect the low pressure protector and
main control board
NO Replace low pressure protector.
Stop the unit.
Open the valve core of the
high pressure valve.
Please refer to the solution of the "Fan
Speed is Operating Outside of
Normal Range" malfunction.