Modern two-chamber refrigerators Ariston with the No Frost system rely on the precise operation of many electronic components to maintain a given temperature. One of the key elements in this chain is the solenoid valve, which controls the supply of refrigerant to the evaporator of the refrigerator compartment. It is this mechanism that switches the flow of freon, allowing the food in the upper compartment to be cooled while the compressor is running.
When the device stops switching correctly, the refrigerator can begin to freeze only in the freezer compartment, leaving the upper compartment warm, or, conversely, freeze the entire contents. Valve diagnostics requires a careful approach, since the problem may lie not only in the solenoid coil, but also in mechanical jamming or control board. It is important for owners to understand the physical principle of operation so as not to replace serviceable parts.
In this article we will analyze in detail the algorithm of actions, the necessary tools and methods for measuring winding resistance. You will learn to distinguish an electrical breakdown from a mechanical breakdown, which will save the budget for calling a technician. Safety When working with electrical appliances, priority number one, so all manipulations are carried out only when the power is turned off.
The principle of operation and the design of the solenoid mechanism
The solenoid valve in refrigerators Ariston is an electromechanical device that opens or closes the passage for refrigerant under the influence of an electric current. At rest, when no current is applied, the spring holds the core in the closed position. When voltage is applied from the control module, a magnetic field appears that retracts the core, opening it to freon.
Structurally, the element consists of a housing with a through hole, a movable rod (plunger), a return spring and an electromagnetic coil. Inductor is the most vulnerable part, susceptible to overheating or short circuit turns. In dual-compressor models or systems with one compressor and one evaporator, there may be several such valves, and they operate in a certain sequence.
The mechanical part is also subject to wear. Over time, scuffs may appear on the rod, and oxidation products or moisture may accumulate inside the housing, turning into ice plugs. Plunger jamming in the closed position will lead to a lack of cold in the refrigeration chamber, while jamming in the open position can cause freezing of the products.
⚠️ Attention: Refrigerant under pressure circulates inside the system. Do not attempt to disassemble the metal valve body or unscrew the tube fittings without the appropriate equipment to pump out freon. Diagnostics is carried out only by external ringing of the coil.
Types of valves in Ariston refrigerators
In Ariston refrigerators, normally closed valves (NC) are most often found. This means that without voltage supply the path to freon is closed. There are also normally open modifications, but they are less commonly used in household appliances of this brand. It is important to know the type of device you have when purchasing spare parts.
External signs of malfunction and initial diagnostics
Before grabbing a multimeter, you need to analyze the behavior of the refrigerator. Symptoms of a broken solenoid valve are often disguised as other problems, such as a freon leak or thermostat failure. However, there are specific signs that specifically indicate a problem with switching refrigerant flows.
The main indicator is temperature imbalance. If the freezer is operating normally (temperature -18°C and below), and the temperature in the refrigerator compartment rises above +10°C, this is the first signal. In this case, the compressor can work continuously, trying to gain temperature, but the cold does not enter the upper chamber.
It is also worth listening to the sounds of the unit operating. A working valve emits a characteristic quiet click when switching modes. If you hear the control module giving a signal (clicking a relay on the board), but there is no characteristic sound of the valve opening/closing, there is a high probability of its failure. Sometimes you can hear the hum of the coil, which indicates an attempt to work, but there is a mechanical obstacle.
Visual inspection is also important. If the valve shows traces of plastic melting, blackening or a burning smell, diagnosis is complete the part requires replacement. Sometimes the problem lies in the oxidized contacts of the connector suitable for the coil, so checking the integrity of the wires is mandatory.
Necessary tools and safety measures
For a high-quality check of the refrigerator solenoid valve Ariston you will need a minimum set of tools, which most home craftsmen have. The main requirement is the accuracy of the measuring instruments and compliance with safety precautions when working with electricity.
First of all, you will need a digital multimeter. Analog dial testers are less convenient for accurately determining resistance in the low range. You may also need screwdrivers to remove the back panel of the refrigerator and insulating tape to restore connections after checking.
List of required equipment:
- 🔌 Digital multimeter with resistance measurement mode (Ohm) and continuity testing.
- 🔧 Set of screwdrivers (phillips and flat) for dismantling protective covers.
- 🧤 Dielectric gloves for protection against accidental electric shock.
- 📱 Smartphone for photographing the connection diagram before disassembling.
Before starting any work, be sure to disconnect the refrigerator from the power supply. Remove the plug from the outlet. Even if you plan to check only the coil, the risk of touching other live parts or capacitors on the control board remains high. Residual voltage can be dangerous, so let the equipment stand unplugged for 5-10 minutes.
☑️ Preparing for diagnostics
Algorithm for checking coil resistance with a multimeter
The most reliable way to determine the integrity of the winding is to measure active resistance. This method allows you to detect an open circuit or short circuit. First you need to gain access to the valve, which is usually located in the lower rear part of the refrigerator, next to the compressor, or hidden under the decorative panel inside the chamber (depending on the model Ariston).
Carefully remove the connector from the valve coil. Do not pull the wires, it is better to use a thin screwdriver to press the lock. Set the multimeter to resistance measurement mode (limit 2 kOhm or 20 kOhm). Touch the probes to the contacts on the coil itself (not on the connector wires, but on the petals of the coil).
The obtained values must be compared with the reference ones. For most refrigerators of the brand Ariston the normal resistance of the valve coil varies within a certain range. If the device shows one (infinity), then it is in the winding. break has occurred. If it shows zero or a value close to zero, a short circuit.
Table of typical resistance values for various components:
| Component | Normal resistance | Symptom of malfunction |
|---|---|---|
| Valve coil (220V) | 1.5 - 3.5 kOhm | ∞ (open) or 0 (short circuit) |
| Valve coil (24V DC) | 100 - 400 Ohm | Significant deviation from the norm |
| Defrost heating element | 200 - 400 Ohm | ∞ (heating element burnt out) |
| Wiring (continuity) | 0 - 2 Ohm | ∞ (broken wire) |
The cold winding has less resistance than the heated one. However, critical deviations (by several times) indicate a malfunction. If the multimeter reading is normal, this does not guarantee 100% serviceability, since the mechanical part may be jammed.
Checking the mechanical part and control signals
If the electrical test showed that the coil is intact, the problem may be hidden in the mechanics or control system. Mechanical jamming of the plunger often occurs due to dirt, moisture or compressor wear products entering the system. In such cases, a magnetic field is created, but the force is not enough to shift the stuck rod.
To check the mechanics, you can gently tap the valve body with the handle of a screwdriver when a signal is sent from the control board. If, after a slight blow, the valve is triggered and cold begins to flow, it means that the mechanism is jammed. However, this is a temporary solution, and replacing the valve will still be needed in the near future.
It is also necessary to check the presence of a control signal. To do this, you need an oscilloscope or a multimeter with a function for measuring frequency/duty factor, or just a voltmeter. At the moment when the refrigerator should supply freon to the fridge compartment (usually this happens cyclically), voltage should appear at the connector contacts. If there is no voltage when the board is working, there is a problem in the wiring.
Sometimes a situation occurs when the valve is electrically and mechanically functional, but does not open due to insufficient pressure in the system or, conversely, excess pressure that the magnet cannot overcome. This already indicates more complex problems with the refrigerant circulation system, requiring the intervention of a professional with a pressure gauge station.
⚠️ Attention: The design of the valves in different Ariston models may differ. Some modern models use pulse valves, which open in short bursts of pulses. Testing such devices with a conventional voltmeter can give false results due to averaging of readings.
Typical errors in diagnostics and replacement
Home craftsmen often make a number of mistakes that not only do not help eliminate the malfunction, but can also lead to additional costs. One of the most common mistakes is replacing the valve without checking the temperature sensors. If the temperature sensor in the refrigerator compartment is lying, it simply will not give a command to open the valve, and the new valve will also remain closed.
Another mistake is ignoring the state of the connectors and wiring. Oxidized contacts create high contact resistance, which prevents the coil from receiving enough power to operate. Visually, the wire may look intact, but inside the wires may be burnt out or oxidized. Always check the circuit from the board to the valve itself.
When installing a new valve, it is important to observe the direction of flow. There is usually an arrow on the body indicating the direction of movement of freon. Installing backwards will result in the system not working and in the worst case scenario the valve may be damaged by water hammer. Also, you should not overheat the valve body with a soldering iron during installation, since the internal plastic may be deformed.
Do not forget about the compatibility of spare parts. Valves from different manufacturers or even different series Ariston may have different operating voltages, thread types or bore diameters. Using the wrong part will either result in system failure or incorrect operation of the refrigerator.
Frequently asked questions (FAQ)
Is it possible to temporarily jam the valve in the open position so that the refrigerator freezes?
Theoretically, this is possible, but it is highly not recommended. If the valve is stuck open, the refrigerator and freezer compartments will cool simultaneously and uncontrollably. This will lead to rapid freezing of food in the refrigerator compartment, increasing the load on the compressor and possibly causing it to fail. In addition, you will lose the ability to regulate the temperature independently.
Why does the valve hum, but does not switch modes?
The hum indicates that electric current is passing through the coil (it is working), and a magnetic field is being created. However, the plunger does not move. Reasons: mechanical jamming of the rod with dirt or ice, weakening of the spring, or insufficient voltage in the network, which does not allow the development of force to shift the jammed mechanism.
Where can I find the voltage marking on the valve?
The marking is usually applied to the plastic body of the coil itself (black or gray). The parameters are indicated there: voltage (for example, 220-240V AC or 12V/24V DC), power and often a symbol of alternating or direct current. It is not necessary to remove the coil from the tube for this; the data is visible from the side or from above.
How much does it cost to replace the solenoid valve?
The cost consists of the price of the spare part and the work of the technician. The part itself for Ariston can cost from 1,500 to 4,000 rubles, depending on the model and manufacturer of the analogue. Replacement work, including pumping out freon, soldering and refilling, usually costs more than the part itself, as it requires special equipment and licenses.
Does a valve malfunction affect energy consumption?
Yes, it does. If the valve is stuck closed, the compressor will run continuously trying to reach the temperature in the refrigerator compartment, causing energy consumption to skyrocket. If the valve does not close tightly or does not work correctly, the cooling efficiency drops and the compressor operating cycle also increases.