Understand the five basic methods: look, listen, touch, measure, and judge (1) Look--observe the conditions of each part. Whether it is a window-type or split-type air conditioner, you can inspect the refrigeration system, Observe the electrical system and ventilation system to see if the fans are operating normally, see if the fuses are intact, and see if there are any oil stains due to refrigerant leakage, etc.
(2) Listen---whether there is a smooth running sound from the compressor, fan, etc., and listen for the sound of collision of fan blades, etc.
(3) Touch---feel the heat and cold in the air vents and other places and the vibration of the casing.
(4) Measurement--use a thermometer to measure the air inlet and outlet temperature, a multimeter to measure the power supply voltage, and a megger to measure the insulation resistance of the air conditioner, etc.
(5) Judgment---judgment analysis, synthesis based on abnormal phenomena, and analysis of the cause of the failure, which should not be done hastily. If you cannot judge, please ask a specialized technician to repair it.
There are also five common faults: leakage, blockage, breakage, burning, and jamming. 1. Leakage: refers to refrigerant leakage; electrical leakage caused by damaged electrical (line, body) insulation, etc.
2. Blockage: refers to the dirty blockage and ice blockage of the refrigeration system; the air filter is blocked; the air inlet and outlet are blocked by obstacles, etc.
3. Break: refers to the disconnection of the electrical circuit; 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 disconnected due to abnormal pressure in the refrigeration system. Wait.
4. Burning: It means that the windings of the compressor motor, fan motor windings, solenoid valve coils, relay coils and contacts are burned.
5. Stuck: refers to the compressor getting stuck, the fan getting stuck, the bearings of moving parts getting stuck, etc.
6. Damage: refers to damage to compressor valves, piston burrs, broken fan blades, and damage to various components.
Detailed explanation of method application: 1. Look: Carefully observe the working conditions of each component of the air conditioner, focusing on the refrigeration system, electrical system, and ventilation system to determine whether they are working normally.
(1) Refrigeration system: Observe whether there are cracks, damage, frost and dew condensation in each pipeline of the refrigeration system; whether there is any collision or friction between the refrigeration pipelines, between the pipelines and the casing, etc. , especially the refrigerant pipeline welding joints, and whether there are leaks at the joints. Any leakage will have oil stains (there is a certain amount of refrigeration oil in the refrigeration system). You can also use a clean soft cloth or soft paper to wipe the pipe welding joints and joints. Check the joints for oil stains to determine whether there is leakage.
(2) Electrical system: Observe whether the fuse of the electrical system is blown, whether the insulation of the electrical wires is intact, whether the circuit board is broken, whether the connections are loose, etc. Especially if the electrical connection is in good contact, wiring screws and connectors can easily become loose, causing poor contact.
(3) Ventilation system: Observe whether the air filter, heat exchanger coils and fins have too much dust; whether the air inlet and outlet are smooth; whether the fan and fan blades are operating normally; the strength of the wind Is it normal? etc.
2. Listen: Turn on the power and listen carefully to see if the air conditioner compressor is running normally, whether there are any abnormal sounds, whether there is any noise from the fan, whether the noise is too loud, etc. When the air conditioner is running, under normal circumstances, the vibration is slight and the noise is small, 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, is not fastened tightly, or does not add vibration-absorbing rubber or foam pads, etc., the vibration and noise of the air conditioner may be intensified during operation. This is especially noticeable when starting up and shutting down.
(2) The compressor vibrates abnormally. The base is poorly installed, the legs are not level, the anti-vibration rubber or anti-vibration spring is poorly installed or the anti-vibration effect is poor, etc. If there is an internal failure of the compressor, such as valve disc breakage, liquid hammering, etc., it will also make abnormal sounds.
(3) Fan impact. Improper installation or deformation of fan blades can cause collision sounds. The fan may collide with the wall casing or chassis. The axis of the fan may move, and the blades may lose their dynamic balance and may make an impact sound. If there is foreign matter in the fan, the blades may collide with it and may make an impact sound.
3. Touch: Touch the relevant parts of the air conditioner with your hands to feel its heat, cold, vibration, etc., which will help 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 of 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 if it is hot but there is a significant difference in temperature between 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 capillary tube at the dryer and outlet should feel warm under normal circumstances (slightly higher than the ambient temperature and basically the same temperature as the end pipe of the condenser). If it feels lower than the ambient temperature or there is dew condensation on the surface or there is a temperature difference in each section of the capillary tube etc. are not normal. Under normal circumstances, the temperature of the suction pipe 200mm away from the compressor should be similar to the ambient temperature.
4. Measurement: In order to accurately determine 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 conditioner. For example, use a leak detector to check whether there is refrigerant leakage; use a multimeter to measure whether the power supply voltage, the voltage of each terminal to ground and the operating current meet the requirements. For air conditioners controlled by a computer, you should also measure whether the potential of each control point is normal, etc.
5. Analysis: Most of the results obtained through the above inspection methods can only reflect a certain local state. All parts of the air conditioner are interconnected and influence each other. One fault may have multiple causes, and one cause may also cause multiple faults. Therefore, a comprehensive comparative analysis of local factors is required to comprehensively and accurately determine the nature and location of the fault. If there is leakage or blockage in the refrigeration system, it will cause abnormal pressure in the refrigeration system, resulting in a decrease in cooling (heating) capacity. However, leakage will inevitably cause insufficient refrigerant, which will reduce both high-pressure and low-pressure pressures; and if blockage occurs in the high-pressure part, high-pressure will increase and low-pressure will decrease.
So it can be corrected according to the fault phenomenon. Difference, so as to determine whether it is leaking or blocked.
Identification and processing of air-conditioning noise: Identification of air-conditioning noise
Due to the widespread use of new technologies such as large-diameter asymmetric blade cross-flow fans, the current split air conditioners have lower noise indicators than previous ones. The products have been greatly improved over the years. Taking a 2500W cooling capacity air conditioner as an example, the maximum noise of indoor units is mostly around 40 decibels, with better products reaching 38 or 39 decibels. Such noise is basically not noticed by people and can be considered not to affect people's rest. The minimum noise of the air conditioner indoor unit is the noise when the air conditioner supplies air at the minimum air volume. It is generally less than 35 decibels and has almost no impact on people. Generally speaking, to evaluate whether an air conditioner is quiet, its maximum noise should be used as the main indicator. Therefore, most air conditioner manufacturers
According to convention, when labeling the noise of air conditioners, they give the maximum noise value, which should It is said that this is a relatively standardized approach. However, some manufacturers make a fuss about the noise value label, claiming in advertisements that "the noise is as low as ×× decibels". However, they do not know that the noise value mentioned here is the minimum noise, and they avoid talking about the maximum noise value. In fact, many air conditioner manufacturers have been able to control the minimum noise of 2500W cooling capacity air conditioners to a low level. Of course, due to different compressors, the difference in noise values ??of outdoor units of air conditioners of different brands with the same cooling (heat) capacity is much greater than that of indoor units. The circulating air volume related to the noise level is an issue that is easily ignored by consumers
. Circulating air volume refers to the volume of air that the air conditioner sucks in from the air inlet and discharges from the air outlet within a certain period of time. It is generally measured in cubic meters per second or cubic meters per hour. When the cooling (heat) capacity of the air conditioner compressor is the same, the air conditioner with larger circulating air volume has a stronger ability to adjust the room temperature. This reason is very simple and easy to understand. However, the increase in circulating air volume requires the indoor unit fan speed to increase and the fan blade radius to become larger, thus increasing the noise level. Therefore, the low noise value of some air conditioners is at the expense of reducing the circulating air volume and sacrificing cooling (heating) capacity. Consumers should compare the small circulating air volume when purchasing.
Air conditioning vibration and noise treatment
Some problems in the installation of air conditioners. Some air conditioners are installed on glass window frames, which often causes vibration of the glass window and brings noise to window air conditioners. If the indoor and outdoor sides of the air conditioner are not tightly separated, it will not only cause the air-conditioning to leak out, but also cause noise from the outdoor side to be transmitted indoors. Therefore, it is best to install the window air conditioner through the wall. The compressor emits abnormal vibration and noise. When the compressor foot bolts are loose, use a wrench to tighten them. The compressor base uses a spring vibration isolation structure. When the product leaves the factory, the base nut is often tightened to compress the vibration isolation spring to the minimum to avoid damage to the refrigeration system due to bumps during transportation and compressor swing. Before installing the air conditioner, the user should first pull out the chassis and loosen the nuts so that the spring can play a vibration-isolating role during the operation of the compressor and reduce its vibration and noise. There are also a few internal parts of the compressor that hit the shell and make intermittent metal knocking sounds during operation. If this kind of fault occurs, the shell can only be opened and repaired. The air conditioner makes other knocking sounds. When the air conditioner is running, the fan tightening screw is loose, causing the fan to shift and produce a knocking sound. This kind of fault must be dealt with in time, otherwise it will not only damage the fan, but also cause the fan to hit the chassis or guide ring and make noise. The gap between the axial flow fan and the guide ring and chassis should be as small as possible in order to improve the working efficiency of the fan. And it is beneficial to throw water to cool the condenser and improve its heat exchange efficiency. If the chassis rigidity is poor or the fan motor is not adjusted properly during installation, the air conditioner will produce the above noise after long-distance transportation or use for a period of time. If you encounter this kind of failure, you can pull out the chassis, readjust the installation position of the fan motor until there is no friction, and then tighten it.