Responsibility
The Chief Mechanic is responsible for maintaining the correct temperature and satisfactory operation of all equipment. A second mechanic or electrician is appointed as the chief mechanic to ensure satisfactory operation of the installation.
Mechanical equipment
Equipment under the responsibility of a second mechanic or electrician includes:
Household refrigeration equipment.
Truck refrigeration machines.
Air conditioners and all related equipment
Gas-Freon 12/22
It is important that gas losses in systems are minimized. The gas used in this system is both expensive and hazardous to health, and therefore Ozone Depletion requires reporting under MARPOL amendments. Therefore, the system must be kept in an absolutely gas-tight state. The refrigerant must not be released into the atmosphere under any circumstances. Before carrying out repair work, the refrigerant should be pumped into a liquid receiver or condenser. The remaining gas must be removed and the area well ventilated.
Maintenance and adjustment (work of 2 mechanics)
Compressor cut-offs i.e. H.P., L.P., L.O. and, where applicable, high temperature shall be maintained in good working order and tested at intervals specified in the maintenance schedule and related reports. In all cases where such tests have been carried out, a corresponding entry must be made in the refrigeration log book.
Automatic expansion valves and controls are precisely specified by the manufacturer. This should be kept in mind when adjustments are necessary and under no circumstances should they be changed randomly.
The oil flowing from the compressor crankcase into the system does not usually cause any operational difficulties, provided that the oil separator valve is maintained in proper operating condition. However, if this valve does not operate, there will be loss of crankcase oil or possibly overheating of the crankcase.
Filters, separators and dryers must be cleaned and recharged or drained regularly to avoid serious operational difficulties. Moisture, oil and foreign substances must always be completely excluded from the gas state. When servicing and operating the entire installation, full use of the operator's instructions should be made.
shutdown
When shutting down a truck, home or air conditioning system, the refrigerant in the chiller must first be transferred to the liquid receiver and the compressor must be turned off at the low pressure control switch. In the event of a plant shutdown due to a power failure, the compressor suction valve must be throttled before restarting and then gradually opened. These precautions are intended to prevent liquid refrigerant from entering the crankcase, which will evacuate the oil charge and damage the pistons and valve gear. The oil pressure control switch must be maintained by subsequent compressor failure.
Internal Refrigeration Chambers Provision (work of 2 mechanics)
All cells must be thoroughly inspected by the chief mechanic and food service officer together. The compartments must be defrosted regularly and kept in an orderly and hygienic condition at all times. Any defective or damaged insulation must be corrected or recorded on the repair list.
