Refrigerators can make various noises during their normal operation, and cracking sounds during startup and shutdown are relatively common. There are a few potential reasons why you might hear these noises:
Expansion and contraction of components: Refrigerators contain various materials, such as metal, plastic, and rubber, which expand and contract as the temperature inside the refrigerator changes. During startup, the compressor (the heart of the cooling system) turns on, causing the refrigerant to circulate through the system and cool down the interior. This process can lead to expansion or contraction of different components, resulting in cracking or popping sounds.
Temperature changes: As the refrigerator cools down the air inside, the temperature in the fridge and freezer compartments drops. The change in temperature can cause the materials used in the construction of the refrigerator to contract, leading to cracking sounds.
Ice buildup: If there is ice buildup inside the freezer compartment, it might crack and make noise when the defrost cycle starts or stops. This is particularly common in frost-free refrigerators that periodically go through defrost cycles to prevent ice buildup.
Water movement: Some refrigerators have a water supply line for ice makers or water dispensers. The water flowing through the lines can cause noise when the refrigerator starts up or shuts down.
Normal operation of the compressor: The compressor itself can make some noise during startup and shutdown. While modern refrigerators are designed to be quieter, you may still hear some noise as the compressor engages and disengages.
It's important to note that while some noises are entirely normal, others could be indicative of a problem. If the cracking sounds are accompanied by other unusual noises, like buzzing, grinding, or continuous loud rattling, it might indicate an issue with the refrigerator's components. In such cases, it's best to have a professional technician inspect and service the refrigerator to ensure it's running optimally and safely. Regular maintenance and cleaning of the refrigerator can also help reduce noise and extend its lifespan.