What are the characteristics of the air curtain cabinet 5 tips to judge the common faults of the air curtain cabinet
The air curtain display cabinet not only has a trendy appearance design, but also is beautiful and elegant; display of the product. At the same time, it makes it convenient and quick for customers to shop and pick up goods; the design of the evaporator is enlarged to improve the heat exchange efficiency.
Common failures of air curtain display cabinets
(1), leakage: refers to refrigerant leakage; electrical (circuit, body) insulation damage caused leakage, etc.
(2) Blockage: refers to the dirty blockage and ice blockage of the refrigeration system; the air filter is blocked; the air inlet and air outlet are blocked by obstacles; the refrigeration oil of the compressor is black, the upper and lower bearing sleeves fall off or Wear, connecting rod fracture, scratches on the friction surface of crankshaft and bearing and friction surface between crankshaft and connecting rod, wear marks on the motor rotor, good suction and exhaust valve plates, etc.
(3) Broken: Refers to the electrical circuit breaking; the fuse is blown; the contact of the overload protector is disconnected due to overheating or excessive current; the contact of the pressure relay is caused by the abnormal pressure of the refrigeration system. Disconnect etc.
(4) Burning: refers to the burning of the windings of the compressor motor, the windings of the fan motor, the solenoid valve coil, the relay coil and the contacts.
(5), card: refers to the compressor is stuck, the fan is stuck, the bearing of the moving part is stuck, etc.
(6) Damage: refers to the damage of the compressor valve plate, the pulling of the piston, the fracture of the fan blade and the damage of various parts, etc.
For the common faults of the air curtain display cabinet described above, we can do the following analysis:
The reason for the burning of the compressor motor:
①The temperature of the motor is too high. Because the motor of the hermetic compressor is cooled by the return air, when the heat pump is heated in winter, the working conditions are relatively poor, especially when the ambient temperature is very low, the heat exchange is small, the refrigerant circulation is also small, and the return air pressure is small. Low, coupled with untimely and incomplete defrosting on the electronic control, will lead to insufficient cooling of the motor and heating of the coil. Such continuous heating will result in high temperature, and PTC is not sensitive to the small current response at low load, so after the compressor is started several times, the insulation will be damaged due to overheating and the motor will be short-circuited and burned before reaching a higher temperature.
②The interior of the refrigeration system is not clean and contains impurities, which corrode and wear the motor coil, resulting in short-circuit burnout.
The reason for the compressor being stuck: From the anatomy of such a faulty compressor, there is no shortage of oil inside the compressor, and the locked shaft is caused by the instantaneous poor lubrication, which is the main reason for the poor lubrication. It is because the oil quality of the lubricating oil has changed that the oil is diluted or the oil level is raised by the refrigerant liquid.
According to the reasons analyzed above, we can make corresponding improvement measures. The basic methods of judging the air curtain display cabinet are: watching, listening, touching, measuring and analyzing.
1. Look: Carefully observe the working conditions of each component of the air curtain display cabinet, focusing on the three parts of the refrigeration system, electrical system and air system, and judge their work Is it normal.
(1) Refrigeration system: Observe whether each pipeline of the refrigeration system has cracks, damage, frost and condensation, etc.; between refrigeration pipelines, pipelines and shells Check whether there is friction between the body and other parts, especially the welding of the refrigerant pipeline, whether there is leakage at the joint connection, and there will be oil pollution in any leakage (there is a certain amount of refrigeration oil in the refrigeration system). Wipe the joint of the pipeline welding and the joint with paper, and observe whether there is oil pollution to judge whether there is leakage.
(2) Electrical system: Observe whether the fuse of the electrical system is blown, whether the insulation of the electrical wire is intact, whether the circuit board is broken, whether the connection is loose, etc. In particular, whether the electrical connection is in good contact, and the wiring screws and connectors are easily loosened, resulting in poor contact.
(3) Ventilation system: Observe whether there is too much dust on the air filter, heat exchanger coils and fins; whether the air inlet and outlet are unblocked; Whether the blade is running normally; whether the wind power is normal, etc.
2. Listen: Turn on the power and listen carefully to see if the compressor of the air curtain display cabinet is running normally, whether there is any abnormal sound, whether the fan is running with noise, whether the noise is too loud, etc. During the operation of the air curtain display cabinet, the vibration is slight and the noise is small under normal circumstances, generally below 50DB. If the vibration and noise are too large, the possible reasons are:
(1) Improper installation. If the size of the bracket does not match the unit, the fixing is not tight, or the vibration-absorbing rubber, foam pad, etc. are not added, the vibration and noise of the air curtain display cabinet may increase during operation. Especially when it is just starting up and shutting down.
(2) The compressor vibrates abnormally. The base is poorly installed, the feet are not level, the shock-proof rubber or shock-proof spring is not installed properly, or the shock-proof effect is not good, etc. If there is a fault inside the compressor, such as broken valve plate, liquid hammer, etc., abnormal sound will also be produced.
(3) The fan hits. Poorly installed or deformed fan blades can cause a crash sound. The fan may collide with the wall shell and the chassis, the axis of the fan moves, and the blades lose balance, and a crash sound will also occur; if there is a foreign object in the fan, the blade will also make a crash sound when it collides with it.
3. Touch: Touch the relevant parts of the air curtain display cabinet to feel its cold, heat, vibration, etc., which is helpful to determine the nature and location of the fault. Under normal circumstances, the temperature of the condenser gradually decreases from top to bottom, and the temperature in the lower part is slightly higher than the ambient temperature. If the entire condenser is not hot or the upper part is slightly warm, or although it is hot but there is a significant difference in the temperature of the upper and lower adjacent pipes, it is abnormal. Under normal circumstances, if you put your finger dipped in water on the surface of the evaporator, it will feel cold and sticky. The dryer and the capillary at the outlet should have a warm feeling under normal conditions (slightly higher than the ambient temperature, and basically the same as the temperature of the pipe at the end of the condenser). etc. are not normal. The temperature of the suction pipe 200MM away from the compressor should be similar to the ambient temperature under normal circumstances.
4. Test: In order to accurately judge the nature and location of the fault, instruments and meters are often used to check and measure the performance parameters and status of the air curtain display cabinet. For example, use a leak detector to check whether there is refrigerant leakage; use a multimeter to measure whether the power supply voltage, the ground current of each terminal and the operating current meet the requirements, and the air conditioner controlled by a computer should also measure whether the potential of each control point is normal, etc.
5. Analysis: Most of the results obtained by the above-mentioned inspection methods can only reflect a certain local state. The various parts of the air curtain display cabinet are related to each other and affect each other. A fault phenomenon may have multiple causes, and one cause may also produce multiple faults. Therefore, the local factors should be comprehensively compared and analyzed, so as to fully and accurately determine the nature and location of the fault.
