How to debug McQuay air conditioner noise

How to debug McQuay air conditioner noise

Noise caused by thermal expansion and contraction when the wall-mounted machine is working: The noise caused by the stepper motor and the synchronous motor. The main reason is that the internal gears of the motor are poorly matched to form abnormal noise. It can be directly changed to eliminate the problem. The other is the air deflector caused by the motor detection reset when the air conditioner is normally turned on and off The short-term continuous collision sound of other parts. This is a normal phenomenon, and the shell can directly consult the user for explanation.

The noise caused by poor performance or damage of the internal fan. It is common that the fan motor produces a low-frequency buzzing sound when the fan motor is working. First, the user's low voltage factor is eliminated. Regarding the cabinet machine emergency, the motor foot pad can be adjusted or thickened while the motor Paste the sound insulation cotton of the appropriate thickness on the back panel on the back will have a better effect. If the effect is not significant, directly change the motor. Regarding the wall-mounted machine. First of all, see whether the internal electrical property can be fixed and the knot will not cause abnormal vibration. If it is loose, the knot will be tight. If not, you can directly change the air supply motor. The noise caused by the working parts of the internal machine is extinguished

Noise during press work: one is due to the formation of parts. The common one is that the cylinder of the press or the start-up capacitor of the press is damaged. The damaged spare parts can be replaced. The other is the performance of the press. It produces low-frequency vibration and hum. It can be eliminated by adjusting and changing the shock-absorbing rubber pad of the press foot and wrapping sound-proof cotton.

　　 The vibration of the compressor during operation causes the collision noise between the pipelines of the external machine, and the fault can be eliminated by adjusting the protective distance between the pipelines of the external machine or adding shock-absorbing cement.

　　 When the outer casing is loose, the separation part collides with each other and vibrates to produce noise. When it is eliminated, first identify the faulty part, and then tighten it.

　　The noise caused by the non-scale of the device, the common ground is loose feet, the fixed part of the bracket and the external machine device are not too high. The noise caused by such elements is generally closed to the external machine. The leveling can remove the noise.

　　The noise caused by the working parts of the external machine disappears

　　 For Xin'an aircraft, neither of the above two methods can send an envoy. The national compulsory standard "Noise Limits for Household and Similar Electrical Appliances" was implemented on August 1, 2005. The relationship between the noise source or vibration source, the path and the user is shown in the figure below. Whether it is a vibration source or a noise source, the path must be passed through before the noise or vibration energy can be transmitted to the receiver or the receiver. The national noise standard for split air conditioners is: split air conditioners with a cooling capacity of 2500-4500W. According to national regulations, indoor unit noise is less than 48 decibels, and outdoor unit noise is less than 58 decibels. In fact, both noise and vibration are presented in an ideal life with "vibration frequency". Take 2500W refrigerating capacity air conditioner as an example, the maximum noise of indoor units is mostly around 40 decibels, and some products reach 38 and 39 decibels. Such noise was not detected at all, and it can be considered that it does not affect people's rest. However, the increase in the recurring air volume requires an increase in the fan speed of the indoor unit and a larger fan blade radius, so the noise value will go up. Other air conditioners have different noise levels according to their horsepower, but the maximum noise level should not exceed 68 decibels. Generally speaking, to evaluate whether an air conditioner can be quiet, its maximum noise should be used as the main trade-off index. Therefore, most air conditioner manufacturers, according to convention, give the maximum noise value when labeling the air conditioner noise. It should be said that this is a comparison scale. way of doing. (The air-conditioning system is equipped with mufflers and vibration-proof equipment in the inlet and outlet ducts, and considers reducing the control wind speed and pressure drop to avoid wind cutting noise and secondary noise).

　　 Air conditioning noise generation:

　　 There are many reasons for the noise of the air conditioner, I will introduce you one by one below!

　　 How loud is the air conditioning noise to be considered normal? According to relevant experts, the country has clear regulations on air-conditioning noise. In the same way, the noise of the air conditioner will also be transmitted from the external unit to the indoor unit or from the indoor unit to the outdoors along the online pipeline (the probability of transmission from the room to the room is of course very small) while the mechanical vibration is constituted as noise. Under the condition that the air conditioner compressor has the same cooling (heat) capacity, the air conditioner with the larger circulation air volume has the stronger ability to adjust the room temperature. This principle is very simple and easy to understand.

　　The noise caused by component damage is common in the cross flow fan, centrifugal fan, and axial fan blades that are damaged and the vibration is formed by poor dynamic balance after operation. When stopping the noise maintenance of the air-conditioning system, we must also consider vibration isolation treatment, otherwise the expected effect will not be achieved, because the vibration source is also a noise source. The sound pressure level at any point in the air-conditioned room is obtained by the logarithmic sum of the direct sound field and the reflected field sound (called the reverberation sound field), which is called the whole sound pressure level.

　　 Air conditioning noise and vibration: After the machine has been used for a period of time (or when the machine is being moved), the system will produce micro-blocking, which will also cause abnormal sounds in the system. If the refrigerant participating in the system is mixed with air during maintenance, the air conditioner is running Not only will there be a difference in cooling and heating, but also a similar "grunting" gasping sound. When the vibration frequency is above 20Hz, it is defined as sound (Note: if the level of sound exceeds the regulations, it is defined as noise), below 20Hz is defined as vibration, and the vibration frequency range of 20Hz~20kHz is the range of human hearing, but The sensitive hearing range is between 50Hz~8kHz. The mechanical noise generated by the air conditioner includes indoor and outdoor units. The original source is often vibration. Vibration will be transmitted from the casing of the machine and the structural parts of the machine to generate vibration or friction between the parts and the parts, and the parts and the casing will be released into the structure. Mechanical noise.

　　 Nowadays, split air conditioners generally use new technologies such as large-diameter cross-flow fans, and the noise index has been greatly improved compared with the products of previous years. Or change the internal machine evaporator.

Ventilation sound outside the air conditioner: When the air conditioner is heating or defrosting, the four-way valve needs to work or stop to achieve the purpose of heating. The ventilation sound generated is a normal phenomenon, no need to worry about it. Affect the normal operation of the machine.

　　 Disposal of air-conditioning refrigerant flow noise:

　　 When there is air supply noise, first check whether there is any foreign body obstruction at the air inlet of the air conditioner. The air inlet is narrow and narrow and the air inlet is not good. The noise is too large, including the dirty air filter caused by the airflow. Do not change the spare parts directly.

　　 Understanding of the indoor sound field. The minimum noise of the indoor unit of the air conditioner is the noise when the air conditioner is supplied with the minimum air volume, which is generally less than 35 decibels, which has no effect on people. When the fan works, because the blades periodically receive the pulsating force of the uneven airflow at the outlet, noise is generated; on the other hand, because the blades themselves and the pressure on the blades are unevenly distributed, the disturbance to the surrounding air and parts during rolling also constitutes rotation Noise; In addition, the turbulent attachment layer, vortex and vortex separation generated when the gas flows through the blades cause the pulsation of the pressure on the blades to generate vortex noise.

　　 Regarding noisy air conditioners with normal openings of the connecting pipes and angle valves inside and outside the air conditioner.