Failure of the cooling system often leads to the fact that the food in one of the chambers begins to deteriorate, while in the other the temperature remains normal. In dual-circuit cold control systems, freon is responsible for switching flows. If this unit fails, the refrigerant stops flowing into the evaporator of the freezer or refrigerator, disrupting the thermodynamic cycle. solenoid valve. If this unit fails, the refrigerant stops flowing into the evaporator of the freezer or refrigerator, disrupting the thermodynamic cycle.
Independent replacement of this part requires not only accuracy, but also an understanding of the operating principles. refrigeration equipment. Connection errors can lead to gas leaks or compressor failure. In this article we will analyze all the stages of diagnostics and replacement so that you can return the equipment to life without calling a technician.
Principle of operation and symptoms of malfunction
The solenoid valve is a solenoid that opens or closes the passage for freon according to an electrical signal from control module. In dual-circuit systems, it directs the refrigerant to either the refrigerator evaporator or the freezer evaporator. When a signal is received that the desired temperature has been reached, the valve switches, stopping the supply of gas to the corresponding circuit.
You can understand that a part requires replacement by its characteristic symptoms. Most often, owners notice that in one chamber the temperature is above normal, and in the other it is too low. For example, food defrosts in the refrigerator compartment, but a “fur coat” forms in the freezer. There may also be a lack of a characteristic click when switching modes.
⚠️ Attention: If you hear a constant hum from the valve, but no switching occurs, this may indicate a stuck solenoid core or low voltage in the power supply.
Diagnostics should begin by checking the voltage at the terminals. If the control module gives a signal, but the valve does not respond, the problem lies in the coil or mechanical jamming. It is important to exclude freon leakage, which may occur when the part body is depressurized.
Necessary tools and preparation
To carry out high-quality repairs, you will need a standard set of tools and some specific materials. Without them, the procedure may be delayed or lead to damage to neighboring nodes. Prepare the workplace in advance by ensuring good lighting and access to the rear wall of the unit.
List of necessary equipment:
- 🛠️ Multimeter for checking the electrical circuit and winding integrity.
- 🔧 Set of screwdrivers (phillips and flat) for dismantling panels.
- 🧊 Hairdryer for carefully thawing ice if the system is frozen.
- 🔩 Blowtorch or torch if soldering of copper pipes is required.
Before starting work, be sure de-energize the refrigerator. Unplug the power cord from the outlet. This is a basic safety rule, which cannot be ignored when working with electrical appliances. It is also recommended to empty the chambers of food to avoid spoilage during long-term downtime of the equipment.
☑️ Preparation for repair
Removing the old solenoid valve
The process of removing the part varies depending on the model of the refrigerator, whether it be Indesit, Atlant or Samsung. Typically the valve is located at the lower rear of the housing, near the compressor. To get to it, you often need to remove the protective metal or plastic panel.
Carefully unscrew the mounting screws and remove the casing. You will see copper tubes coming from the condenser and compressor, as well as the valve itself with the wires that go to it. Before disconnecting the tubes, make sure that there is no pressure in the system, although in most household models it bleeds itself when depressurized.
Proceed according to the following algorithm:
- Take a photo of the wire connection diagram so as not to confuse them during assembly.
- Disconnect the electrical connector from the coil solenoid.
- If the valve is soldered, carefully heat the joints with a torch and remove the part.
- If threaded connections are used, use an appropriate wrench, being careful not to turn the tubes.
When dismantling, be careful with copper tubes - they are very soft and easily deformed. Any crack or break will require additional soldering and charging the system with refrigerant, which is difficult to do at home.
What to do if the valve is stuck?
If the threaded connection does not yield, do not use excessive force. Treat the joint with a penetrating lubricant (eg WD-40) and leave for 15-20 minutes. Gently tapping the threads with a wrench can help break down the oxides. If this does not help, you will have to cut out part of the tube and solder a new valve through the couplings.
Selecting and installing a new part
Purchasing a new spare part is a critical moment. Solenoid valves differ in supply voltage (usually 220V or 12V), type of refrigerant (R600a or R134a) and the diameter of the connecting pipes. Using an unsuitable part will lead to incorrect operation of the system.
To select an analogue, use the markings of the old device. Compare technical specifications:
| Parameter | Description | Importance |
|---|---|---|
| Voltage | 220V or 12V (indicated on the coil) | Critical |
| Freon type | R600a (isobutane) or R134a | High |
| Pipe diameter | Internal diameter in inches (for example, 1/8") | High |
| Normal position | Normally closed (NC) or open (NO) | Critical |
Installation of a new valve is carried out in the reverse order of dismantling. If you use soldering, be sure to fill the tubes with nitrogen or purge them to avoid the formation of an oxide film inside the system, since oxides can clog the capillary tube. the most important step, since oxides can clog the capillary tube.
When connecting the wires, strictly follow what was done earlier. photo or diagram on the case. An error in polarity (for some models) or connecting to the wrong contact can burn the new valve or control board. After mechanical installation, check that all elements are securely fastened.
Checking for leaks and refilling
After installing the part, the system becomes open, so checking for leaks is mandatory. Even a microscopic hole will lead to a gradual release of freon and repeated failure after a few months. To check, pressurized nitrogen is used.
Connect the pressure gauge station to the service fitting and pump in nitrogen. Bring the pressure to the operating value (usually 10-15 atmospheres for R600a and a little higher for R134a). Apply a soap solution liberally to all soldering and joints.
Carefully inspect the seams:
- 🫧 The appearance of bubbles indicates a leak - it needs to be redone. connection.
- 📉 A drop in pressure gauge readings over time indicates a hidden leak.
- ✅ Stable pressure for 30-60 minutes confirms tightness.
⚠️ Attention: Never use oxygen or air from the compressor for pressure testing. Oxygen mixed with compressor oil can cause an explosion, and moisture in the air will lead to the formation of acid inside the system.
If the system is sealed, it is necessary to create a vacuum to remove moisture and air. Only then can you start charging with refrigerant, strictly observing the weight indicated on the label inside the refrigerator.
Typical replacement mistakes
Even experienced professionals sometimes make mistakes that ruin all the work. Beginners often encounter problems due to inattention or haste. Knowing the typical “rake” will help you avoid them.
One of the most common mistakes is ignoring the cleanliness of the system. Getting dust, moisture or flux residues inside copper tubes is catastrophic for capillary tube the compressor. Always seal the open ends of the tubes immediately after cutting or soldering.
Another common problem is incorrect selection of the analogue. Externally, valves may look the same, but have different flow areas or actuation voltages. Installing a “look-alike” valve may result in the refrigerator working but not freezing properly.
Frequently asked questions (FAQ)
Is it possible to replace the solenoid valve without evacuating the system?
Theoretically, it is possible if you act very quickly, but in practice this will result in moisture entering the system. The moisture will freeze in the capillary tube, causing an ice jam, and the refrigerator will stop freezing. Vacuuming is an obligatory stage of high-quality repairs.
How much does it cost to replace a valve in a service center?
The cost consists of the price of the part itself (usually from 1000 to 3000 rubles) and the work of the technician. In the service, the price for work can vary from 2000 to 5000 rubles, depending on the complexity of access and the need to refill with freon.
Why did the new valve immediately burn out after switching on?
The most likely reason is a malfunction of the control module, which supplied the wrong voltage or signal. There may also be a short circuit in the wiring or incorrect connection of the contacts. Always check the control circuit before installing a new part.
Is it necessary to change the filter drier when replacing the valve?
Yes, this is a mandatory requirement. When the system depressurizes, moisture enters it, which the old filter can no longer effectively retain. Replacing the filter drier guarantees long and stable operation of the refrigerator.