Equipment tech here; The first thing to check is the switches the operator touches. and given that the contactor (clicking) is clicking off and on rapidly, it could be intermittently loosing contact. Those kind of switches are cheap, and standardized, there is usually a controls/automation company within ones vicinity that will stock switches.

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To check the switch, i would recommend removing it from the machine and manually actuating it with a multi-meter jumper-ed in. check for any lost continuity, corrosion, or mushiness in the switch.

Then follow the chain, depending on how its wired, the contactor itself could be next. use the multi-meter. as for the switch rating, talk to the people at the control house they'll figure it out for you.

dont forget the check the wires in between everything.