Service life of commercial refrigeration equipment and its reliability depend on observance of operating rules, on keeping it clean and using as intended.
The main conditions of the refrigeration equipment continuous operation are the following:
- mounting high performance;
- qualified maintenance;
- execution of all operating rules by personnel.
Mounting, that is pre-starting and starting-up of refrigeration equipment, should be performed by a mechanical engineer certified for performance of such types of works and for maintenance of refrigerating units. In the period between maintenance and repairs, commercial enterprise personnel should perform the following:
- monitoring of unit state, its proper loading and dashboards installing, and of condensate removal system;
- visual inspection of machine compartment, at which pipelines leakproofness is checked (appearance of oil traces in split-type joints indicates the refrigerant leakage );
- daily cleaning and product soaking after work finishing;
- removal of snow deposit (frost layer with a thickness more than 3 mm);
- visual checking of temperature in refrigerated enclosure as per a thermometer.
Equipment operation reliability and reduction of its operation costs largely depend on proper performance of these duties by personnel. Commercial refrigeration equipment is installed in the dry, coldest place in a compartment. For normal and economical operation the refrigeration equipment should be installed in places not exposed to direct effect of sun rays, and as far as possible but not less than 2 m from heaters and other heat sources. It is not recommended to open the door towards warm air flow. When placing the equipment, the air free access should be provided to the unit condenser, therefore it must be installed at a distance of not less than 0.2 m from the wall. The equipment with a built-in unit should also have the air free access to machine compartment grilles. The equipment should be kept clean. The outer part of it should be periodically cleaned with a wet flannel and wiped dry. The inner walls should be washed with soap, then rinsed with clean water and thoroughly dried every week. In order to achieve the minimum refrigeration losses, sliding sashes of showcases and counters, doors of refrigerating cabinets and chambers are recommended to open only if necessary and for a short period of time. The products in showcases and cabinets are placed with a gap so the distance to glass or walls would not be less than 10 cm. Non-observance of this requirement negatively affects the temperature mode. The lower the unit ambient air temperature is, the lower the condensation pressure and consequently higher refrigeration capacity is and its operation is more economical. The maximum permissible air temperature around the refrigerating machine is 25 … 35 ° C. At higher air temperature, condensation pressure reaches the upper limit and the controller automatically switches off the unit. At normal operation malfunction of the refrigeration equipment, it is required to switch off the compressor motor at once and to call a mechanical engineer who services the refrigeration unit.
The following is prohibited at refrigeration equipment operation:
- to permit unauthorized persons to examine, repair the refrigerating machine and to adjust control instruments;
- to perform the above mentioned works by own forces;
- to touch the movable parts of refrigerating unit during operation and automatic shutdown;
- to remove the frost from evaporator by mechanical method with the help of scrapers, knives and other objects);
- to obstruct refrigerating unit and passages with foreign objects hampering technical inspection and check of its operation, and also interfering the normal air circulation that cools the condenser;
- to switch on the refrigerating machine when a magnetic starter cover, a connector block of electric motor, a pressure regulator and other instruments are removed from the unit, as well as from its rotating and movable parts.
Long-term operation of refrigerating machine depends on observance of the following rules:
- the equipment should be loaded with products only by reaching the normal temperature mode;
- the quantity of products to be loaded should not exceed the allowable norm of one-time equipment loading;
- the products should be loosely laid or hanged together at 8-10 cmdistance from the walls for free motion of cool air and better, uniform products cooling;
- it is prohibited to store the products on evaporators, to cover the wire shelves and products with paper, cellophane etc.;
- it is not allowed to store foreign objects in the equipment to be cooled;
- prevent the combined storage of various types of products passing an odour to one another;
- closed doors of refrigeration equipment should be tightly pressed to the casing all around, they ought to be open as seldom as possible and for a short period;
- there should be no frost on the evaporator, the cool air must freely circulate between its ribs.
Causes that negatively affect the equipment operability:
- equipment usage in overload mode. First of all it is referred to refrigerated showcases that serve for goods presentation rather than for their storage. Showcases overcharge on goods presentation level leads to overtensioned mode of the unit operation that reduces its service life. The load height at goods presentation in refrigerated showcases or freezing showcases must not exceed the level marked on a side wall;
- nearly all refrigeration equipment is meant for operation at ambient air temperature to 25 °С. In summer conditions the temperature in commercial premises reaches 30 °С and higher. It also negatively affects the unit operation. Saving on installation of additional ventilation systems or conditioning systems can cause the refrigeration equipment failure;
- irregularity of routine maintenance. Especially it is referred to spring-summer period when the machine compartment is cluttered with poplar wool and dust.