A cooling system adjusts the temperature of air blown from evaporators by adjusting the opening of a flow rate adjustment valve that adjusts the flow rate of coolant flowing in a cooling coil, and is provided with: a plurality of evaporators which each use a fan to suck the heated air discharged from a plurality of electronic equipment provided inside an equipment room, cool that air by heat exchange with the coolant flowing inside the cooling coil, and then blow cold air into the equipment room; and a condenser which is provided above the plurality of evaporators and which cools the coolant that circulates naturally between the evaporators. An apparatus for operating the cooling system when in an abnormal state is characterised in being provided with: a deviation information detection means which successively detects, for each of the plurality of evaporators, the deviation between the maximum cooling capacity and the current cooling capacity during operation; and a fan control means which reduces the speed of or stops the rotation of the fan for evaporators among the plurality of evaporators having deviation information which exceeds a preset abnormality set value.