Carrier 38MBR series Service Manual page 28

DIAGNOSIS AND SOLUTION (CONT)
Error Code
Malfunction decision conditions
Supposed causes
Troubleshooting:
Power off, then restart the
unit 2 minutes later. Does a
Is cool air blowing from
the indoor air outlet?
Check system for leaks.
Are any leaks present?
Check system for blockages
and clear blockages if present
Table 18—Refrigerant Leakage Detection Diagnosis and Solution (EC)
EC
Define the evaporator coil temp.T2 of the compressor just starts running as Tcool. In the
beginning 5 minutes after the compressor starts up, if T2 <Tcool-35.6°F(Tcool-2°C)
does not keep continuous 4 seconds and this situation happens 3 times, the display area
shows "EC" and AC turns off.
S
T2 sensor faulty
S
Indoor PCB faulty
S
System problems, such as leakage or blocking
problem still remain?
Yes
No
No
Check the T2
sensor. Is it
Yes
securely attached?
Replace the indoor
Yes
Repair the leak and
recharge the refrigerant
28
Yes
PCB