As an indispensable equipment in industrial and commercial places, the normal operation of refrigeration units is crucial for maintaining environmental comfort and product quality. However, as the usage time increases, the refrigeration unit is inevitably prone to various malfunctions. This article introduces the five commonly used steps in the maintenance of refrigeration units: "touch, look, listen, check, and analyze".
1, Touch: Judging device status through tactile sensation
Touch "refers to touching the relevant parts of the refrigeration equipment with your hands to feel its temperature, vibration, and other conditions. The following are specific application scenarios:
Compressor: After the compressor is running, touching the suction pipe, exhaust pipe, compressor itself and other parts with your hand can determine whether its temperature is normal. Under normal circumstances, the intake pipe is cold and the exhaust pipe is hot. If the temperature of the entire compressor is too high, it may indicate an internal malfunction.
Evaporator: A normally functioning evaporator surface should be cool. If you feel overheated or not cool when touching the evaporator surface with your hand, it may be due to insufficient refrigerant or internal blockage of the evaporator.
Condenser: The temperature of the condenser should gradually decrease from top to bottom, with the lower temperature slightly higher than the ambient temperature. If the entire condenser is not hot or the upper part is slightly warm, it may indicate that there is a malfunction inside the condenser.
2, Watch: Observe the operating status of the equipment
'Watching' refers to carefully observing the working conditions of each component of the refrigeration equipment, with a focus on the refrigeration system, electrical system, and air system.
Refrigeration system: Check whether there are cracks, damages, frost and condensation in the various pipelines of the refrigeration system. Pay special attention to whether there are leaks at the welding and joint connections of the refrigerant pipeline.
Electrical system: Check whether the fuses in the electrical system are blown, whether the insulation of the electrical wires is intact, whether the circuit board is broken, and whether the connections are loose.
Wind system: Observe whether there is excessive dust accumulation in the air filter, heat exchanger coils, and fins, whether the air inlet and outlet are unobstructed, and whether the fan and blades are operating normally.
Check the system components: whether the high and low pressure values are normal. First, check whether the appearance of the air conditioner is intact and whether each component is working properly. Check if there are any fractures in the refrigeration system pipelines and if there are any oil stains at the welding points. If there are oil stains at the welding points, there may be leakage. Check if there is any looseness in the plug of the electrical components, if the positions of the connecting copper pipes are correct, and if there are any copper pipes touching the shell.
3, Listen carefully to the sound of the device running
Listening "refers to carefully listening to the sound emitted by refrigeration equipment during operation, especially the sound of the compressor and fan running.
Compressor: During normal operation, the compressor has slight vibration and low noise. If the compressor makes abnormal sounds, such as metal impact sound, friction sound, etc., it may be an internal malfunction.
Fan: There should also be no noise when the fan is running. If the fan blades are installed improperly or deformed, it may cause collision noise; If there are foreign objects inside the fan, the blades will also make a collision sound when they collide with it.
4, Check: Check the operating parameters and status of the equipment
'Check' refers to using instruments and meters to inspect and measure the performance parameters and status of refrigeration equipment.
Leak detector: used to check whether there is refrigerant leakage in the refrigeration system.
Multimeter: used to measure whether the power supply voltage, ground current of each terminal, and operating current meet the requirements.
Temperature: Used to measure the internal temperature of refrigeration equipment and determine whether it meets design requirements.
Monitoring/Controller: Check if the parameters of the refrigeration unit monitoring/controller are normal and meet the design requirements.
Low pressure; High pressure; Balance pressure during shutdown; Inlet pipe temperature; Exhaust pipe temperature; Compressor temperature; Condenser; Evaporator; filter; Capillary tube; Working current; Operating voltage and other parameters.
5, Analysis: Comprehensive judgment of the cause of the malfunction
Analysis "refers to the comprehensive comparative analysis of the results obtained from the first four steps, in order to accurately determine the nature and location of the fault.
Fault location determination: After determining the cause of the fault, it is necessary to further determine the specific location of the fault in order to carry out targeted maintenance or replacement.
Case: A refrigeration unit frequently experiences high-pressure protection shutdown during operation. The maintenance personnel found through comprehensive analysis that the poor cooling effect was caused by the low flow rate of the cooling water pump. After replacing the water pump, the unit resumed normal operation.
Refrigeration unit maintenance is a complex and meticulous task that requires maintenance personnel to possess rich professional knowledge and practical experience. By comprehensively applying the five steps of "touch, look, listen, check, and analyze", the cause of the fault can be accurately determined and corresponding maintenance plans can be formulated. At the same time, regular maintenance and upkeep are also important means to extend the service life of refrigeration units and reduce failure rates. I hope this article can provide readers with useful references and inspirations.
