For Daikin or York air conditioner, they have this easy self-diagnosis feature that enable user to know what have went wrong, so that user can get a better idea to talk to technician for them to better prepare themselves to come and solve the issue.
To start the self-diagnostic process, first press the Cancel button on the remote control while facing to the air conditioner for about 5-10 seconds. There will have Double Zero “00” digit appear at the center of the screen. Next, press the Cancel button again, the “00” will jump to next alphanumeric. Keep pressing the Cancel button until there’s a Long Beep sound and record down the alphanumeric that appear on the screen. That’s Error Code that you will need in order to know what is going wrong for your air conditioner unit.
Next check the Error Code from Daikin’s website (Click Here) or you may refer to the Error Code sheet below to understand further.
Download the list of error code here (PDF File).
For example, if you get the error code U0 (U-Zero), it mean shortage of refrigerant, so you can request service agent to come to refill the refrigerant (R410, R401A, R22, etc).
If you get E1 (E-One), it mean the outdoor unit PCB is broken and might need to replace one.
Call your local service agent and inform them the Error Code so that they can help to fix the issue faster.