Carrier 40MB C Series Service Manual page 23

Refrigerant Leakage Detection diagnosis and solution (EC)
Error Code
Malfunction decision conditions
Supposed causes
Power off, then restart the
Check cool air blowing out
from indoor air outlet
Check leakage of system
check blockIng of system and
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 35 Tcool 35_F does not keep
continuous 4 seconds and this situation happens 3 times, the display area will show "EC"
and AC will turn off.
S
T2 Sensor faulty
S
Indoor FCB faulty
S
System problems, such as leakage or blocking
unit 2 minutes later.
Yes
No
No
clear the blocking
Fig. 30 – Troubleshooting
Check if T2 sensor
Yes
Yes
Replace indoor PCB.
Yes
Repair the leakage and
recharge the refrigerant.
23