Sudden defrosting of supplies or suspicious silence of equipment is always stressful for the owner. Often users are faced with a situation where the refrigerator seems to be humming, but the food inside has already lost its appearance, or, conversely, it is silent, but it is still cold inside. Understanding exactly how working equipment behaves is the first step to identifying serious breakdowns.
Diagnostics begins long before opening the back cover and using the multimeter. Careful monitoring of the behavior of the unit in everyday conditions allows you to weed out false alarms and focus on real problems. Initial assessment the state of the equipment is based on the analysis of sound signals, temperature indicators and visual signs of the operation of the main components.
In this article we will analyze the algorithm of actions that will help you accurately determine whether it needs your refrigeration unit is in urgent repair or a simple adjustment is enough. We will consider both indirect signs and methods of direct testing of the electrical circuit.
Primary visual inspection and sound analysis
The first thing you should pay attention to is the nature of the sounds produced by the device. A working refrigerator works cyclically: it turns on, gets cold, turns off and is silent until the next cycle. If you hear a continuous hum without pauses or, conversely, absolute silence while the light is on, this is a signal to action.
Listen carefully to the operation of the motor. Normal operating sound - this is a smooth, low-frequency hum of the compressor, which may be accompanied by a rare gurgling of the refrigerant in the tubes. Any extraneous noise, such as knocking, clanging, whistling, or a loud humming sound similar to a transformer, indicates mechanical problems.
- 🔊 A uniform hum is a sign of normal compressor operation.
- 🔊 Clicking noises during startup may indicate problems with the start relay.
- 🔊 A whistle or hissing often indicates a freon leak or capillary blockage.
Also perform an external inspection of the rear wall. If you see oily spots or drips in the compressor area, this is almost guaranteed to mean a violation of the system's tightness. The presence of oil on the tubes is a 100% sign that the system is depressurized and requires calling a technician with leak detection equipment.
⚠️ Attention: If you hear a loud bang or a crackling sound accompanied by the smell of burnt wiring, immediately disconnect the device from the network. Further operation may lead to a fire.
Checking the temperature conditions and operation of the evaporator
The main function of the device is cooling. To understand whether the equipment copes with the task, it is necessary to measure temperatures. Do not rely solely on the feel of your hands, as the subjective perception of cold is often deceptive, especially if the food has already been defrosted.
Use a household thermometer, placing it in a glass of water in the center of the refrigerator compartment. In the freezer, the check is carried out in a similar way. For modern models with the system No Frost it is important that the cold is distributed evenly, without local heat zones.
Pay attention to the formation of ice. In drip systems, a “fur coat” periodically appears on the back wall, which then melts. If you see a huge layer of ice that does not melt, or, conversely, complete dryness when the compressor is not working, these are signs of a malfunction of the thermostat or defrost sensors.
- ❄️ The temperature in the refrigerator compartment should be in the range of +2...+5°C.
- ❄️ In the freezer, the thermometer should be drop below -18°C.
- ❄️ Uneven cooling (warm at the top, cold at the bottom) is a sign of circulation problems.
Diagnostics of the compressor and start relay
The heart of any refrigerator is the compressor. It is he who pumps the refrigerant through the system. If the motor does not start, but the light in the chamber is on, the problem lies in the electrical circuit or the motor itself. The test begins by listening to startup attempts.
After being plugged into the network, a working refrigerator should start within a few minutes. If you hear a quiet click, followed by a hum that lasts 3-5 seconds, and then a shut-off click, this is a classic symptom of a stuck compressor or faulty start relay.
In some cases, you can carefully (with the power off!) remove the cover from the back and check the start relay. It looks like a plastic box placed over the contacts of the compressor. If the ringing of a fallen core is heard inside the relay or traces of burning are visible, replacing it can revive the device.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| Silent, there is light | Thermostat or relay is faulty | Low |
| Beeps for 5 seconds and clicks | The compressor is stuck or the relay is burned out | High |
| Working without stopping | Freon leakage or seal wear | Medium |
| The housing gets very hot | Condenser clogged or oil problem | Average |
Analysis of the operation of the defrost system (for No Frost)
In models with the system No Frost a separate circuit is responsible for removing moisture and defrosting the evaporator, including Heating element, timer and sensors. If this system fails, the evaporator becomes overgrown with ice, blocking air circulation.
Visually this is manifested by the fact that the refrigerator is humming, the compressor is working, but there is no cold inside. The fan may be noisy or jammed due to ice. To confirm the diagnosis, partial disassembly of the freezer chamber or rear wall is often required.
Checking the integrity of the defrosting heating element is done with a multimeter in dial mode. If the circuit rings and defrost does not occur, the timer or defrost sensor may be faulty. These elements are located in accessible places and can be changed without complex equipment.
- 🌡️ Ice on the back wall inside the chamber is a sign of defrosting failure.
- 🌡️ The fan does not spin due to ice on the blades.
- 🌡️ Water under the vegetable boxes indicates a clogged drainage hole.
⚠️ Attention: When defrosting ice with a knife or sharp objects, there is a high risk of breaking the evaporator. Use only a hair dryer or natural defrosting for 24 hours.
Checking the electrical circuit with a multimeter
For those who have basic electrical skills, the most accurate method will be to check the circuits with a device. Before starting work, make sure that the device is disconnected from the network. You will need a multimeter set to resistance measurement mode (Ohm).
First of all, the integrity of the power cord and plug is checked. Then the thermostat rings: in the “on” position it should close the circuit. The resistance of the compressor windings also provides important information: there must be certain resistance values between the contacts (usually from 10 to 60 Ohms), and infinity between the housing and the contacts.
If the multimeter shows an “open” on the motor windings, it means the compressor has burned out and requires replacement. This is a complex procedure that requires evacuation of the system and charging with freon.
Normal winding resistance values (approximate):Starting winding: 30-40 Ohm
Working winding: 10-15 Ohm
Total resistance: the sum of the two above
What to do if you don’t have a multimeter?
You can assemble a simple “control” from a 220V light bulb and two wires. However, this method is less accurate and more dangerous, since it does not show the amount of resistance, but only the presence of contact.
When you need to call a professional technician
There are a number of situations when self-repair is not only useless, but also dangerous. If diagnostics show a refrigerant leak, special equipment is required for soldering, evacuation and charging. You cannot simply “top up” freon - this will disrupt the operation of the system.
Replacing a compressor is also a complex job. It requires knowledge of the technology for soldering copper tubes, the use of nitrogen during soldering (to prevent the formation of oxides inside) and accurate selection of oil. An error at any stage will lead to rapid breakdown of the new motor.
You should also contact a technician if the problem lies in the electronic control module. Modern refrigerators are crammed with complex electronics, and without circuits and experience, re-soldering microcircuits can be more expensive than buying a new device.
- 🛠️ Soldering of tubes and working with gas is required.
- 🛠️ It is necessary to replace the compressor or filter-drier.
- 🛠️ The electronic control unit is faulty (the board has burned out).
⚠️ Attention: Prices for spare parts and services of technicians may change. Before starting work, always check the final cost of diagnostics and repairs so that it does not exceed the economic feasibility of restoration.
Frequently asked questions (FAQ)
Why does the refrigerator work non-stop, but does not freeze well?
Most often this indicates a refrigerant leak (freon) or loss compressor performance. Also, the reason may be a violation of the door seal, due to which warm air constantly flows inside.
Is it possible to turn on the refrigerator immediately after transportation?
If the refrigerator was transported lying down, you need to let it stand upright for at least 4-8 hours (preferably a day). This is necessary so that the oil flows back into the compressor. If you were transporting standing, 2-3 hours is enough.
How to distinguish the noise of a fan from the noise of a compressor?
The noise of a compressor is low-frequency vibration and hum. Fan noise (in No Frost systems) is a higher-pitched, whistling or humming sound that may change when the door is opened (as the fan often turns off when opened).
What should you do if there is water inside the refrigerator?
Check the drainage hole on the back wall of the refrigerator compartment. It could become clogged with crumbs or ice. Clean it with a special stick or soft wire, then pour in some warm water to check the drainage.