**Operational specifications of the cold storage system controller** The FC-785 PC controller has three operation modes, as follows: 1. Stand Bonhaler Mode: Turns on only if hot gas is needed for another controller to initiate defrost. If the set ambient temperature plus the forced cooling temperature (P 306) is exceeded, the cooling is also activated, even if the controller in the subnet is not yet cooled. Adjustable control parameters are located in the internal settings of the parameters. 2. Defrost modes: choose from several defrost modes such as; No defrost, solar defrost, electric defrost or hot gas defrost. 3. End of defrosting: After defrosting is finished, the cooler and fan will be blocked during the time of external water impulse. After this time, the fan will start if the fan delay time (P 521) has expired. If the fan delay time (P 521) is negative, the fan is activated for (P 521) minutes before the cooling starts. 4. Alarm: If an alarm input is activated, the cooler and fan will stop and the alarm LED will turn on.