An unpleasant hum coming from the kitchen can turn a quiet evening into a test for the nervous system. If your refrigerator starts to hum, this does not always mean that it is broken. Often the source of sound is a violation of operating conditions or natural processes in the cooling system. However, a change in the acoustic background cannot be ignored, as this may be the first signal of a serious malfunction.
In this article we will look in detail at why extraneous noise appears, how to distinguish normal operation of the equipment from a breakdown, and what you can do yourself. You will learn which components require attention, how to check the installation is correct, and when you really should call a technician. Understanding the nature of sound is the key to saving time and money on repairs.
First of all, it is worth assessing the nature of the sound. A monotonous hum, which is heard when the engine is running, is often the norm for many models. But if clicks, gurgling or vibration are added to the hum, changing its tone, this is a reason for a deeper diagnosis. Let's figure out where to start looking for the problem.
Normal operation versus malfunction: how to distinguish
Modern refrigeration units are complex devices in which physical processes are constantly occurring. Compressorcompressing the refrigerant inevitably makes sound. In older models with linear motors, this sound was loud and low. Newer inverter systems are quieter, but can also become humming at peak load times. It is important to understand that a smooth, unobtrusive hum against the background of a running engine is the normal mode.
The situation changes if the nature of the sound has changed dramatically. For example, if previously the equipment worked almost silently, but now it hums like a tractor. Or if the hum is accompanied by strong vibration of the body, which can be felt by touching the wall. Extraneous sounds should also alert you: whistling, grinding metal or intermittent humming.
⚠️ Attention: If the hum is accompanied by the smell of burning or melted wiring, immediately disconnect the device from the network and do not try to turn it on again until the technician arrives.
For accurate diagnostics, it is useful to know the structure of your unit. In models with the system No Frost noise may be produced by the fan that blows on the evaporator. If an ice crust has frozen in the chamber, the blades may touch the ice, creating a characteristic crackling or humming sound. In drip systems, the most common noise is the motor-compressor itself or the freon flow in the tubes.
Installation problems: the most common cause of vibration
One of the most common reasons why a refrigerator hums and vibrates is its incorrect installation. If the device is not level or too close to the wall, vibration from the operating compressor is transmitted to the body, floor and even to objects standing nearby. This creates a resonance effect, increasing the hum several times.
Check whether yours refrigerator is stable. It often happens that one of the legs does not reach the floor, and the entire weight falls on three supports, causing distortion. In this case, the body begins to “shake” every time the engine is started. It is also important to maintain the gap between the rear wall of the device and the wall of the room. The minimum distance should be 5-10 cm for normal air circulation.
☑️ Checking the installation of the refrigerator
Another important nuance is contact with furniture. If the refrigerator is built into a kitchen unit or stands close to the cabinets, vibration can be transmitted to them, causing the entire kitchen to hum. In this case, it is necessary to move the pieces of furniture apart or place damping materials between them, for example, pieces of rubber or a special seal.
How to set the level correctly?
Use a building level for adjustment. Place it on the top shelf of the refrigerator (inside). If the bubble is misaligned, use a wrench or hand (depending on model) to twist or unscrew the front legs until the bubble is perfectly centered. The rear legs are usually non-adjustable.
Internal elements and foreign objects
Sometimes the source of noise is inside the chambers. Heavy pots, glass jars or bottles placed on shelves close to each other or to the walls begin to rattle at the slightest vibration. This sound is often perceived as the humming of the unit itself. Check the contents of the refrigerator and remove objects that may come into contact.
Particular attention should be paid to the system No Frost. If this particular area is humming, it may be the fan. Over time, the fan bearings wear out or ice freezes on the shaft, leading to imbalance and noise. Also, a hum can occur if the blades touch the “fur coat” that has grown on the evaporator.
The table below shows the main sources of internal noise and methods for eliminating them:
| Source of noise | Symptoms | Elimination method |
|---|---|---|
| Shelves and containers | Rattling, clinking of glass | Rearrange objects, remove touching walls |
| Fan (No Frost) | Constant hum, crackling | Defrosting, replacing the fan |
| Refrigeration circuit tubes | Vibration of metal tubes | Carefully move the tubes away from each other |
| Condensation tray | Rattling at the bottom at the back | Fix or place a sealant |
If you find that the tubes at the back of the unit are humming, do not rush to bend them with your hands. The metal there is thin and can burst, which will lead to a freon leak. It is better to use a soft damper, for example, a piece of foam rubber or rubber, to isolate the tubes from touching.
Faults of the compressor and start relay
When all external factors are excluded, and the refrigerator continues to hum, the problem may lie in the “heart” of the device - the compressor. Engine wear is a natural process. Older models are louder than new ones. However, if the hum has become unnaturally strong, metallic or is accompanied by knocking, this is a sign of a serious breakdown.
Often the culprit of the problems is starting relay. This small element is responsible for starting the engine. If it is faulty, the compressor may hum but not start, or may start with a loud clicking and humming noise. In such cases, the motor operates with overload, which quickly disables it.
⚠️ Attention: Replacing the starting relay yourself is only possible if you have the skills to work with electricians. Do not forget that capacitors can retain a charge even after being disconnected from the network.
It is also worth checking the fastening of the compressor itself. The motor is suspended on springs inside the casing. If one of the springs has jumped off or burst, the compressor begins to bang against the walls of the casing during operation, producing a loud knock and hum. In this case, disassembly of the rear part of the unit and a visual inspection of the suspension are required.
Problems with the refrigerant and defrost system
Sometimes it is not the mechanical part that is humming, but the refrigerant flow itself. If a plug has formed in the system or the circulation of freon is disrupted, you can hear a characteristic gurgling sound that turns into a hum. This often happens after improper transportation (if the refrigerator has been lying on its side) or due to a gas leak.
In models with a full defrost system, a hum may occur during the defrost cycle. The heating element heats the evaporator, and melting ice can create noise as it flows into the drain. If the drainage hole is clogged, the water begins to boil and gurgle, creating unpleasant sounds. Regular defrosting and cleaning the drainage helps to avoid this problem.
It is important to note that if the refrigerator begins to hum more than usual after defrosting, you may have been too hasty in turning it on. The water in the tubes and the compressor may not have had time to evaporate or flow into the drain, creating hydraulic noise.
When a call to the technician is necessary
There are a number of symptoms in which self-repair is not only useless, but also dangerous. If you have checked the installation, removed unnecessary items, defrosted the unit, but it continues to hum with increasing force, it’s time to call the specialists. Especially if the hum is added to the lack of cold in the chambers.
A technician will be needed in the following cases:
- 🔴 The compressor hums, but does not start, and after a few seconds a click is heard and the hum stops (cyclic hum).
- 🔴 There is a smell of burnt wiring or plastic.
- 🔴 You can see an oily coating on the floor under the refrigerator or on the pipes at the back.
- 🔴 The body of the refrigerator gets very hot, but it is warm inside.
- 🔴 You hear a metallic grinding or knocking sound from inside the motor.
Professional diagnostics will allow you to accurately determine whether it is necessary to change the compressor, refill freon, or simply replace the sensors. Remember that complex repairs require special equipment: a vacuum pump, a pressure gauge station and tools for soldering.
Is it possible to lubricate a compressor if it is humming?
Lubricating a working compressor “from the outside” is impossible and useless. It is hermetically sealed. If it hums due to lack of lubrication inside, it means that the motor’s life has been exhausted and needs to be replaced. Attempts to drill the casing and fill in oil will lead to depressurization and final failure.
Why does a new refrigerator hum?
New equipment may hum during the break-in period (the first 2-3 weeks). Also check that all shipping bolts and films have been removed. If it hums very strongly from the first day, it may be a defect - contact the store for a replacement under warranty.
Does the voltage in the network affect the hum?
Yes, low voltage in the network causes the compressor to work with overload, which increases the hum and can lead to overheating of the windings. If your light often fluctuates, it is recommended to install a voltage stabilizer.
Is it dangerous if the refrigerator hums constantly?
A constant hum without interruptions indicates that the refrigerator does not reach the desired temperature and the motor does not turn off. This leads to overheating and a fire hazard. You need to check the tightness of the doors and the operation of the thermostat.
How to reduce the hum of an old refrigerator?
In addition to adjusting the legs, you can place a piece of thick rubber under the compressor (vibration insulation). Sometimes it helps to install the unit away from the walls or in a niche with sound-absorbing material, but not interfering with ventilation.