A lot is missing here before anyone can sensibly comment - what else is on the circuit, how clean is the incoming supply, what sort of load is the 'cooler' - (small fridge, container, building air con ?) Did the cooler work before the AFDD was installed - is it a new circuit to an old machine or all new?

the problem is that a lot of factors can cause an AFDD to operate, arcs is one, but certainly not the only.
how are you testing the AFDD without the cooler ?

mike.

A lot is missing here before anyone can sensibly comment - what else is on the circuit, how clean is the incoming supply, what sort of load is the 'cooler' - (small fridge, container, building air con ?) Did the cooler work before the AFDD was installed - is it a new circuit to an old machine or all new?

the problem is that a lot of factors can cause an AFDD to operate, arcs is one, but certainly not the only.
how are you testing the AFDD without the cooler ?

mike.

Other devices on the same circuit work perfectly but as soon the cooler(40L 58W mini bar) connected on the circuit it trips down the AFDD. It's a new installation. The AFDD warning led indicates the arc detection but the same situation for other same brand coolers.

Is the minibar a compressor type cooler ? it may be that the motor start-run switch or the thermostat of that cooler model arcs during start up.  Other users of this forum have reported that not all AFDDs are equally sensitive and it may be that the cooler is missing an arc  suppressor.  I presume the minibar works OK on a non AFDD circuit just with RCD protection? Have you queried this with the cooler  importer/ manufacturer ?

Sadly at the time of typing there are almost no ways to debug this kind of problem systematically, short of watching the waveform on a scope as the cooler trips in and out.

The other line of attack is the AFDD maker. At least one has issued firmware updates to handle an over-sensitivity issue.

Mike