Common troubles and maintenance of household central air conditioning

1、 Leakage of common faults: refers to leakage of refrigerant; leakage caused by damage of electrical (line, body) insulation, etc Blocking: refers to the dirty blocking and ice blocking of the refrigeration system; the air filter is blocked; the air inlet and outlet are blocked by obstacles, etc Disconnection: refers to the disconnection of electrical circuit; fuse fusing; contact disconnection of overload protector due to overheating or excessive current; contact disconnection of pressure relay due to abnormal pressure of refrigeration system, etc Burn: it means that the winding of compressor motor, fan motor, solenoid valve coil, relay coil and contact are burnt Card: refers to compressor stuck, fan stuck, bearing stuck of moving parts, etc Damage: refers to compressor damage, piston galling, fan blade fracture and various parts damage, etc 2、 The basic methods of judging the common faults of central air conditioning the basic methods of judging the common faults of domestic central air conditioning are: look, listen, touch, measure and analyze 1 View: refrigeration system: Observe whether there are cracks, damages, frosting and condensation in each pipeline of the refrigeration system; whether there is any friction between the refrigeration pipelines, between the pipelines and the shell, especially whether there is any leakage at the welding part of the refrigerant pipeline and the connection part of the joint Any leakage part will have oil stains (there is a certain amount of refrigeration oil in the refrigeration system) Clean soft cloth and soft paper can also be used to wipe the welding part and the connection part of the pipeline At the joint, observe whether there is oil stain to judge whether there is leakage Electrical system: observe whether the fuse of the electrical system is fused, whether the insulation of the electrical wire is intact, whether the circuit board is broken, whether the connection is loose, etc In particular, if the electrical connection is in good contact, the connection screws and connectors are easy to loose, resulting in poor contact Ventilation system: observe whether there is too much dust on the air filter screen, heat exchanger coil and fins; whether the air inlet and outlet are unblocked; whether the fan and blades operate normally; whether the wind force is normal, etc 2 Listen: turn on the power and listen carefully to whether the operation sound of air conditioner compressor is normal, whether there is abnormal sound, whether there is noise in fan operation, whether there is too much noise, etc During the operation of the air conditioner, the vibration is slight and the noise is small under normal conditions, generally below 50dB If the vibration and noise are too large, the possible causes are: 1) improper installation For example, the size of the bracket is not consistent with the unit, fixed or not, or damping rubber, foam plastic cushion, etc., which can make the air conditioner vibrate and noise increase when it is running Especially when it is just started and stopped, Zui is significant 2) abnormal vibration of compressor The base is not installed well, the feet are not level, the shockproof rubber or spring is not installed well or the shockproof effect is not good In case of internal failure of compressor, such as valve plate breakage, liquid hammer, etc., abnormal sound will also be generated 3) fan impact Poor installation or deformation of fan blades may cause collision sound The fan may collide with the wall shell and chassis, the axis of the fan moves, and the blade loses its dynamic balance, which will also produce a crash sound; if there is any foreign matter in the fan, the blade will also collide with it 3 Touch: touch the relevant parts of the air conditioner by hand to feel the cold, heat, vibration, etc., which is helpful to judge the nature and position of the fault Under normal conditions, 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 whole condenser is not hot or the upper part is slightly warm, or although it is hot, the temperature of the two adjacent pipes is significantly different, it is abnormal Under normal conditions, put the finger dipped in water on the surface of the evaporator, and it will feel cold and sticky Under normal conditions, the capillary at the dryer and outlet should have a warm sense (slightly higher than the ambient temperature, basically the same as the temperature of the last section of the condenser pipe) If the temperature is lower than the ambient temperature or there is dew condensation on the surface and there is temperature difference in each section of the capillary, it is abnormal Under normal conditions, the temperature of the suction pipe 200 mm away from the compressor shall be similar to the ambient temperature 4 Measurement: in order to accurately determine the nature and position of the fault, it is often necessary to check and measure the performance parameters and state of the air conditioner with instruments and meters For example, use a leak detector to check whether there is refrigerant leakage; use a multimeter to measure whether the power supply voltage, terminal to ground voltage and running current meet the requirements; for a computer-controlled air conditioner, measure whether the potential of each control point is normal, etc 5 Analysis: most of the results obtained by the above inspection methods can only reflect some local state Each part of the air conditioner is related to each other and affects each other There may be many reasons for a fault phenomenon, and one reason may also produce many faults Therefore, it is necessary to make a comprehensive comparative analysis of local factors, so as to comprehensively and accurately determine the nature and location of the fault If the refrigeration system leaks or is blocked, the pressure of the refrigeration system will be abnormal, resulting in the decrease of refrigeration (heating) capacity However, the leakage will inevitably cause the shortage of refrigerant, which will reduce the pressure of high pressure and low pressure If the blockage occurs in the high pressure part, the phenomenon of high pressure rising and low pressure decreasing will occur Therefore, it can be distinguished according to the fault phenomenon, so as to judge whether it is leakage or blockage