CLF is Control Line Failure.
• The ATS48 monitors the control voltage via the 2 terminals (CL1-CL2) on the 'control unit'.
• This fault is encountered very infrequently as it is usually transient. The voltage must rise again in order for the switch mode power supply to be present during operation CLF fault trip threshold:
• Voltage less than approx. 40% of 220 V for the ATS48…Q (threshold = 88 V).
• Voltage less than approx. 40% of 110 V for the ATS48…Y (threshold = 44 V).

Probable causes:
• Loss of the line voltage for at least 200 ms on terminals CL1-CL2.
• Voltage thresholds exceeded.

Remedies:
• Check the value of the voltage at terminals CL1-CL2: if the voltage is within the tolerances, replace the power board.
• Check the quality of the line supply.

Released for:Schneider Electric India