Installation Manual and Owner's Guide
 Page 42
Troubleshooting
mrcool.com
More recent models now feature automatic correction of wiring/piping errors. Press the "check 
switch" on the outdoor unit PCB board for 5 seconds until the LED displays "CE”, indicatomg that 
this function is working, Approximately 5-10 minutes after the switch is pressed, the "CE" disappears, 
meaning that the wiring/piping error is corrected and all wiring/piping is properly connected.
How To Activate This Function
1.
 Check that outside temperature is 
above 5℃. (This function does not work 
when outside temperature is not above 5
℃)
2. Check that the stop valves of the liquid 
pipe and gas pipe are open.
3. Turn on the breaker and wait at least 2 
minutes.
4. Press the check switch on the outdoor 
PCB board unit LED display "C E".
Correct
Terminal
block
Liquid/
Gas pipe
Outdoor unit
Indoor unit B
Indoor unit A
B
A
B
A
Incorrect wiring
Terminal
block
Liquid/
Gas pipe
Outdoor unit
Indoor unit B
Indoor unit A
B
A
B
A
Incorrect wiring
Terminal
block
Liquid/
Gas pipe
Outdoor unit
Indoor unit B
Indoor unit A
B
A
B
A
Check switch
LED display
Automatic Wiring/Piping Correction Function
NOTE
The function for the automatic wiring/piping correction illustrated below is intended for use by 
a licensed electrical technician only. 










