Normally, noise is perceived in two ways by the user, either by vibration or by sound. In general, refrigerators have noise limits related to manufacturers’ standards, but in some cases seem to be making more noise than they should.

Noise can be perceived at specific times, such as when the compressor starts and stops, or it may be continuous during operation.

Identifying the noise can be difficult to perceive, but generally it may be associated with the following factors:

Metal Vibration

Generally metallic vibrations are due to the tubing tapping on other metal parts or to each other.
Tubing lines need to be assessed for mechanical contacts and are usually identified when the compressor is in operation.
To solve this problem it’s necessary to avoid contact of the tubing, which can be done with a sponge or other material that absorbs vibration.
It’s also possible that noise is a result of the refrigerator not being properly leveled. Thus it’s always important to consider the manufacturer’s recommendations to avoid problems.

Compressos incorrectly mounted to refrigerator base

The compressor must be properly secured so that during its operation the transfer of noise to the refrigerator is minimized.
The shock damper must never be compressed. This is an indication that it was fastened too tightly during installation and needs to be loosened a little. But be careful, the compressor must always be firmly attached to the refrigerator base.

Starting noise in the refrigerator

During compressor startup and shutdown it’s natural that vibration occurs due to the internal rotation of the compressor kit and noise coming from there is considered natural.
For some models of compressors which use an amperometric relay, during startup it’s common to hear a noise similar to a clack that should also be considered normal noise.
However, in some cases this might seem strange to the end user.
Be attentive once again to the compressor’s attachment, because it shouldn’t be in direct contact with the refrigerator’s wall. The contact points are the compressor’s passer tubes and base.
Also, the mechanical thermostat present in some refrigerators, a component responsible for starting and stopping the compressor generates a noise similar to a snap, and it’s also a normal noise. However, it’s always worth checking to see if it’s properly secured on the refrigerator.

Whistle in evaporator

This noise resembles a low whistle and is due to gas circulation and evaporation and is usually considered normal.

Other noise sources

In some situations where there is over or under voltage on the network, protection of the compressor may occur by thermal tripping. This noise is similar to a click. For these cases it’s important to assess whether the compressor is working under appropriate conditions and if the thermal protector is suitable for that application.
It’s also possible that the compressor presents internal and time of use related problems and in this case the only thing to do is replace it with a new compressor.
Other components such as fan, transformer, and stabilizer, among others can be noise sources and should be analyzed.
Prepare a checklist with this list of different noise types. When attending a customer, it’ll be easier to identify the possible causes.