Carrier 40QSM009DS Service Manual page 101

16.3.5 Refrigerant Leakage Detection diagnosis and solution (EC)
Error Code
Malfunction conditions
Potential Causes
Trouble shooting:
Power off, then restart the
unit 2 minutes later. Does a
problem still remain?
Is there cool air blowing
out from indoor air outlet?
Check system for leakages.
Are any leakages present?
Check System for blockages
and clear blockages if present
EC
Define the evaporator coil temperature T2 of the compressor
starts running as Tcool.
If the following occurs 3 times, the display shows "EC" and the
unit switches off:
In the first 8 minutes after the compressor starts up, if T2 ＜
Tcool－2℃ is not maintained for 4 seconds and compressor
running frequency is not higher than 50Hz for 3 minutes
Faulty T2 sensor
●
Faulty indoor PCB
●
System problems, such as leakage or blockages
●
Yes
No
No
Yes
Check the T2
sensor. Is it
Yes
securely attached?
Yes
Replace the indoor
PCB
Repair the leakage and
recharge the refrigerant
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