cooling pipe of the refrigeration system

Figure 1: The refrigerating machine for the industry.

The operation sound of the refrigerating machine is unavoidable. The fan rotating, fan blade rubbing with the air would make the noise that is normal. But severe, sudden, harsh, irregular noises are worth our attention. The refrigerating machine includes a compressor, a radiator, a pressure-reducing device, etc.

Five Causes of Your Refrigerating Machine Noise

First by hearing the sound, we are able to find the probable source of the abnormal noise, and then we can troubleshoot it. Here are some common causes and solutions.

At first, you should find the reason from the parts that are easy to troubleshoot and observe.

Anchor Screws

The refrigerating machine is fixed on the ground. If the anchor bolts become loose after a long time of operation, the machine will be unstable and make noise. This failure can be solved by replacing the anchor bolts. Besides, you could also install a shock absorber, which firmly fixes the machine to the ground.

industrial shock absorbers

Figure 2: Shock absorbers.

Connecting Pipeline

There are various sizes of pipes on the refrigerating machine that connect the refrigerating machine, equipment to cool, and other auxiliary devices. If the connecting screws become loose, the noise will be generated after the operation. The solution is to fix the pipes and equipment.


The air-cooled refrigerating machine with a fan is composed of a fan cover and blade. If the blade is deformed by an external force, it will make noise when it rotates. Besides, the fan cover will also cause noise due to dust and debris. By replacing the blade and regularly cleaning the debris above the fan, you can reduce the noise.

Then we observe whether the following parts have abnormal sounds.


Most of the abnormal sound of the pump is due to the water quality. If the water is not clean enough and causes the pump pipe to be blocked, resulting in abnormal sound and noise. You should treat the circulating water to meet the requirements of the refrigerating machine.

Abnormal Sound of the Compressor

If the compressor makes an abnormal sound, it could be a very important problem. As the heart of the refrigerating machine, compressor sound should attract our attention.

Copeland Compressor ZB58KQE-TFD-550 3PH 50/60HZ 2900/3500RPM 380-420V/460V

Figure 3: Copeland Compressor ZB58KQE-TFD-550

There are three main reasons for the abnormal sounds of the compressor.

* Liquid refrigerant in the compressor

Once the liquid refrigerant enters the compressor, it can not be compressed but produces the liquid pressure to cause the liquid strike in the internal structure, resulting in vibration or abnormal sound. In addition, the excessive refrigerant will dilute the refrigerating oil, causing mechanical parts to be worn.


You can check whether the refrigerant is excessive, and release extra refrigerant; check the opening degree of the expansion valve, and adjust it timely.

* Excessive refrigerant oil

It will cause the liquid strike.


You can inspect the situation of the refrigerant oil in the compressor and clear excess oil.

* Abnormal sound from the compressor cylinder and crankshaft

Generally, it is due to the lack of lubricating oil, resulting in abnormal wear of internal components of the compressor. And it will make abnormal sounds, affect the normal work of the compressor, shorten the service life of the equipment.


In this case, the compressor should be repaired or replaced. Note that regular inspection of the refrigerating machine and compressor can effectively avoid this fault.

Some personnel have encountered this failure, because the oil return pipe is bad, leading to the loss of refrigerating oil. As a result, it causes damage to the crankshaft sleeve of the compressor, making a large noise, but also aggravating its wear.

a crankshaft

Figure 4: The compressor crankshaft.

In the normal use of the refrigerating machine, some small noise would be made. But the irregular and sudden noise shall cause our attention.

In a word, the reasons for the abnormal noise of the refrigerating machine are loosening of the connecting screws, abnormal sound of fans and the water pump, excessive refrigerant, and refrigerating oil.

Compressor Noise Control Measures

The compressor is widely used in industrial production, but the noise produced by the compressor during its operation seriously affects the physical and mental health of the staff, so it is urgent to control the noise of the compressor. What are the solutions to compressor noise control?

Sound Insulation Measures

It is an effective measure to install the sound insulation room outside the compressor and seal the noise source with the sound insulation cover.

The walls around the sound insulation cover and the top structure are shown in the design drawing of the sound insulation room.

In order to avoid resonance, the outer layer adopts a double-layer galvanized steel plate of different thicknesses, as well as the structure of the constrained damping layer. The C-shaped steel keel is used as the skeleton and the frame is used as the support.

the sound insulation room for the compressor

Figure 5: The sound insulation room.

Noise Elimination Measures

The silencer is a device that can not only allow airflow to pass through but also effectively reduce noise. It is mainly used to control and decrease the noise from the inlet and outlet of all kinds of aerodynamic equipment or transmitted along the pipeline.

Based on the principle, silencers can be divided into dissipative, reactive, compound, and varied-frequency types. The dissipative silencer has good middle- and high-frequency muffler performance, while the reactive silencer is excellent in low- or middle-frequency noise elimination, which can effectively achieve the role of noise control of the compressor.

a silencer for the compressor

Figure 6: A silencer.

Vibration Reduction Measures

In the noise control of air conditioning units, you should pay more attention to the vibration reduction treatment of the unit and pipeline system, and at the same time, the ventilation and heat dissipation of the unit should be fully considered.

By installing elastic supports between the machine and the foundation to isolate the mechanical vibration, you can suppress the noise and reduce the solid sound transmission.

For air conditioners and heat exchangers, the shock absorber and pad can be installed on the seat (the shock absorber is placed on the shock pad) to reduce the transmission of machine vibration to the foundation. Therefore, the vibration of the machine has been effectively isolated to reduce noise and solid sound transmission.

shock pads used to the compressor

Figure 7: Shock pads.

I hope these solutions will be helpful for you.

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