Carrier 40MBDAQ - Page 35

40MBDAQ: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
35
DIAGNOSIS AND SOLUTION (CONT.)
P6 (Low ambient temperature protection)
Description: If the sampling voltage is not 5V, the LED displays a failure code.
Recommended parts to prepare:
• Wiring mistake
• Over load protector
• System blockages
• Outdoor PCB
Troubleshooting
Low pressure protection
Are the low pressure
protector and the main control
board wired properly?
Reconnect the low pressure protector
and main control board.
NO
Check the low pressure protector.
Method: Disconnect the plug.
Measure the low pressure protector resistance.
If the protector is normal, the value is 0.
NO
Is the low pressure
protector normal?
Replace the low pressure protector.
NO
Check the outdoor ambient temperature.
YES
Is it too low? Stop the unit. YES
Check the valve core of
the high pressure valve.
NO
Is it fully opened?
Open the valve core of the
high pressure valve.
NO
Replace the outdoor main board.
YES
Does a problem still exist? The problem is solved.NO
Check if the refrigerant level is sucient.
If not, add more refrigerant.
YES
Does the system function properly?
Check whether the refrigerant
system is functioning properly
NO