Modern refrigeration technology is a complex engineering mechanism, where each element performs a strictly assigned role in maintaining the temperature regime. One of the key components that ensures proper circulation of the refrigerant is valve. Many unit owners do not even suspect the existence of this part until they encounter cooling problems or strange sounds when the compressor operates.
Understanding this What is a valve in a refrigerator for?allows you not only to quickly diagnose a malfunction, but also to avoid unnecessary expenses on calling a technician to solve simple issues. In this article we will analyze in detail the design of various types of valves, their effect on the operation of the system No Frost and the signs by which you can determine the failure of a part.
The main task of any valve in a cooling system is to control the flow of matter. Depending on the type of refrigerator and its design features, this may be controlling the movement of freon or adjusting the air flow inside the chambers. Solenoid valve (electromagnetic) is the most common type in two-chamber models, as it is responsible for switching the operating modes of the evaporator.
Principle of operation solenoid valve in two-chamber models
Refrigerators with two or more chambers often use one compressor, but require independent temperature control in each compartment. This is where solenoid valvecomes into work, which is an electromechanical device that blocks or opens the passage for the refrigerant. When the electronic control module detects that the temperature in the freezer has reached the set value, it sends a signal to close the valve.
At this moment, the circulation of freon through the freezer evaporator stops, and the refrigerant begins to flow only into the evaporator of the fridge compartment or stops circulating altogether if the cycle completed. Without this device, it would be impossible to implement the function Full No Frost or an independent cooling system, where the temperature in each compartment is regulated separately. The principle of operation is based on electromagnetic induction: when voltage is applied, the coil creates a magnetic field that draws in the core and changes the position of the shut-off element.
⚠️ Attention: Solenoid valves are sensitive to voltage surges in the electrical network. If your region has unstable electricity, it is recommended to use a surge protector or stabilizer, since a burnt-out valve coil is a common cause of equipment failure.
Structurally, the device consists of a housing, an inductor, a plunger and a spring. In the normal state (without current), the valve can be closed or open depending on the model, but most often in refrigerators it is normally closed. Tightness connections are critically important, since even a microscopic leak of freon through a loosely closed valve will lead to a loss of performance of the entire system.
The role of the check valve and the defrost system
In addition to controlling the freon flow, it is often used in the evaporator defrost system check valve. Its function is to prevent the backflow of liquid or gas, which is especially important in systems with a heat pump or a complex defrost circuit. In the context of defrosting No Frost, the valve can be used to isolate certain sections of the circuit so that hot refrigerant during defrosting does not get into places where it is not provided for by the design.
There is also the concept of an air valve (damper), which regulates the supply of cold air from the freezer compartment into the refrigerator compartment. Although technically not always a hydraulic valve, that is what it is commonly called. It opens at the command of the thermostat when it becomes too warm in the upper chamber. Damper can have a mechanical or electrical drive.
It is important to understand the difference between these elements. If the solenoid controls liquid or gaseous freon in a sealed circuit, then the air damper operates with atmospheric air inside the chambers. Malfunction of any of these elements leads to an imbalance of temperatures. For example, if a check valve in a defrost system is stuck open, the defrosting process may not proceed correctly, causing the air ducts to freeze.
Why is the valve humming?
The humming or buzzing of a solenoid valve often indicates that there is voltage on the coil, but the core cannot fully retract. This may be caused by mechanical contamination, deformation of the housing or low voltage in the network.
Main signs of a malfunction of the valve system
Diagnosis of valve malfunctions requires careful monitoring of the operation of the refrigerator. Since these parts do not have a visual indication (except, perhaps, a click when switching), problems are signaled by a change in the operating mode of the unit. Symptoms can vary, from complete absence of cold to periodic failures.
One of the first signs of failure of the solenoid valve is uneven cooling of chambers. If the freezer is operating normally, but the temperature in the refrigerator compartment is above normal (or vice versa, everything freezes), this indicates that the freon flow is not switching. It is also worth paying attention to the operation of the compressor: if it works non-stop, trying to gain temperature, but there is no result, the valve may be stuck in the closed position.
In the case of air dampers, a sign of a malfunction is the formation of a “coat” or ice in the area of the air ducts, as well as condensation on the products. If the damper does not close, too much cold air enters the refrigerator compartment and food in the upper compartment begins to freeze. And vice versa, if it is tightly closed, it will become warm in the upper chamber.
Another important symptom is extraneous sounds. Knocking, clicks or buzzing in the area of the back wall or compressor compartment may indicate valve attempts switch. If you hear frequent clicking sounds every few minutes, this may mean that the electronic module is sending signals, but the mechanical part of the valve is not responding as expected.
Table: Comparison of valve types and their functions
To better understand the differences between the components, consider their main characteristics in the comparison table. This will help to identify which part is being discussed in the instructions or when talking with a technician.
| Valve type | Location | Main function | Drive type |
|---|---|---|---|
| Solenoid | Near the compressor or condenser | Switching freon flows between chambers | Electric (electromagnet) |
| Reverse | In the refrigerant circuit | Prohibition of refrigerant reverse | Passive (medium pressure) |
| Air damper | Between freezer and refrigerator compartments | Adjustment of cold volume air | Electrical or mechanical |
| Safety | On the compressor or receiver | Pressure release at critical values | Spring mechanism |
The table shows that although all these elements are called valves, their purpose and principle of operation are radically different. The solenoid valve is an active control element that requires power, while the check valve operates automatically due to the pressure difference in the system. Understanding this difference is necessary when searching for spare parts.
Diagnostics and performance testing methods
Checking the valve begins with visual inspection and listening. When you turn on the refrigerator or change the operating mode (for example, after the defrost time has expired), a distinct click should be heard from the solenoid valve. If there is no click, but the compressor is running, this is the first sign of a problem. However, the absence of sound does not always mean that the valve itself is broken - the control module may be faulty.
For more accurate diagnostics, use a multimeter. It is necessary to check the resistance of the solenoid coil. Normal resistance values are usually in the range from 1.5 to 3 kOhm (depending on the model and manufacturer, for example Whirlpool or Electrolux). If the device shows an open circuit (infinity) or a short circuit (close to zero), the coil must be changed. The presence of voltage on the contacts is also checked at the moment when the valve should switch.
☑️ Diagnostics of the solenoid valve
Checking the air damper requires removing the plastic panel in the refrigerator compartment. Visually assess whether there are any mechanical obstacles to the movement of the damper (ice, foreign objects). When turning the temperature regulator or entering the service mode, the damper should move. If the damper drive is humming, but it stays still, the gear inside the motor may be broken or the damper itself is frozen.
⚠️ Attention: When diagnosing the electrical part of the valves, be sure to unplug the refrigerator. Working under voltage in conditions of possible humidity (condensation) is dangerous to life and can lead to electric shock.
Replacing the valve: difficulties and nuances
Replacing the solenoid valve is a procedure that requires the qualifications of a technician, since it is associated with a violation tightness of the refrigeration circuit. Simply unscrewing the old one and screwing on the new one will not work. The system contains freon, which must be pumped out, then solder a new element, create a vacuum and refill the system with refrigerant.
The process of replacing the air damper is technically simpler and can often be done independently if you have access to a spare part. However, there are nuances here too. New dampers may have a different mounting or connector configuration than the original ones. In addition, after replacement, calibration may be required through the service menu so that the electronics “understands” that a new element is installed.
When ordering a spare part, it is important to pay attention not only on the model of the refrigerator, but also on the marking of the valve itself. Manufacturers can use different suppliers of components for the same model of equipment. Article parts must match completely. The use of analogues with other parameters (voltage, bore diameter) is unacceptable.
Prevention and extension of service life
In order for the valve system to operate for a long time and without failure, it is necessary to monitor the general condition of the refrigerator. Regular defrosting (for models Drop or combined) prevents the formation of excess ice, which can damage the mechanical parts of the dampers. It is also important to ensure good ventilation of the rear wall so that the compressor and adjacent elements do not overheat.
Power surges are the main enemy of solenoid valves. Installing a voltage stabilizer will protect not only the valve, but also the expensive electronic control module. If you notice that your refrigerator is starting to get louder or that there are intermittent clicking noises, do not ignore these signals. Timely contact with a specialist can prevent a more serious breakdown, such as compressor failure due to operation in emergency mode.
It is also worth mentioning the cleanliness of the condenser. If it is clogged with dust, the pressure in the system increases, which increases the load on all components, including the valves. Simple annual cleaning of the rear grille of the refrigerator with a vacuum cleaner or brush is an effective preventive measure.
Is it possible to operate the refrigerator if the solenoid valve does not work?
Technically, the refrigerator will work, but the cooling efficiency will be extremely low. One of the chambers (usually the refrigerator) will stop freezing, since freon will only circulate through the freezer. Long-term operation in this mode is harmful to the compressor, which will work non-stop, trying to compensate for the lack of cold.
Why does the valve click every 5-10 minutes?
Frequent clicking may indicate a malfunction of the thermostat or temperature sensor, which sends false signals to switch. This may also be a sign of “sticking” of the valve itself, when it tries to open, but cannot due to contamination or a mechanical defect, and the system tries again.
How much does it cost to replace the valve?
The cost consists of the price of the part itself (from 1000 to 5000 rubles depending on the model) and the cost of the work of the technician. Since vacuuming and refilling with freon are required, the job is rated higher than simply replacing a household part. The exact amount can be found out only after diagnosing a specific model.
Does the tilt of the refrigerator during transportation affect the operation of the valve?
The tilt itself does not break the valve, but can lead to oil leakage from the compressor into the circuit where the valve is located. Oil can jam the valve mechanism or create an "oil lock." Therefore, after transportation, the refrigerator must stand upright for several hours before turning it on.