Replacing a failed thermostat is one of the most common reasons why a household refrigerator ceases to maintain the set temperature mode. The model RKT 2 is one of the most common analogues used to restore the performance of equipment of various brands. The correct connection of this element is critically important, since it is the one responsible for the cyclic operation of the compressor.
In the process of self-repair, it is important not only to connect the wires correctly, but also to correctly install the capillary tube in the evaporator. Errors at this stage can lead to the unit working without stopping or, conversely, not starting at all. In this article we will analyze a detailed algorithm of actions, technical nuances and safety measures.
Purpose and operating principle of RKT 2
Thermoregulator RKT 2 is an electromechanical device that controls the temperature inside the refrigeration chamber. Its main task is to open and close the electrical power supply circuit of the compressor depending on the sensor readings. When the temperature rises above the set one, the contacts close, starting the motor.
The design of the device includes a bellows filled with refrigerant and a capillary tube that transmits the thermal effect to the sensitive element. When the tube cools, the pressure inside the bellows drops, which leads to the opening of the contacts. Setting accuracy directly affects energy consumption and safety of products.
It is important to understand that RKT 2 is often a replacement for older or rare models of thermostats. However, it on and off parameters may differ from the factory ones, which requires additional adjustment after installation. Without this, the refrigerator may not reach the required cold or create excessive ice.
Necessary tools and measures safety
Before starting any work on electrical equipment, you must completely turn off the power to the refrigerator. Unplug the plug from the socket and make sure there is no voltage at the contacts. Ignoring this rule may result in electric shock or failure of the electronics.
To carry out quality repairs, you will need a minimum set of tools. The presence of good lighting in the work area will also significantly speed up the process and reduce the risk of errors when switching wires.
- 🔧 Screwdrivers (phillips and flat-head) for removing panels and terminals.
- ✂️ Side cutters or wire cutters for cutting excess length of wires.
- 🔌 Indicator screwdriver or multimeter for checking the circuit.
- 🧤 Dielectric gloves to protect hands.
⚠️ Attention: The capillary tube of the thermostat is very thin and fragile. In no case bend it at an acute angle and do not allow creases to appear, as this will disrupt the circulation of gas and the device will stop responding to temperature.
Removing the old thermostat
The process of removing the faulty element begins with removing the protective panels. Depending on the refrigerator model, the thermostat may be located inside the chamber, under the top cover or in the control unit. Carefully unscrew the mounting screws and remove the plastic casing.
The next step is to disconnect the regulator handle. Usually it is simply removed by hand, but in older models it can be secured with a locking screw that needs to be unscrewed. After this, access to the thermostat housing opens.
Before disconnecting the wires, it is recommended to photograph the connection diagram or sketch out the color markings. This will help avoid confusion when installing a new device RKT 2. Then unscrew the nut securing the housing and carefully pull the capillary tube out of the evaporator.
☑️ Preparation for replacement
Connection diagram and switching of wires
The most critical stage is connecting the electrical contacts. Thermoregulator RKT 2 usually has three main contacts, the markings of which may differ depending on the manufacturer, but the operating principle is the same. It is important to correctly identify the incoming phase and control circuits.
The standard circuit involves the presence of a contact for connecting the mains wire, a contact for starting the compressor and a contact for the lighting lamp (in some modifications). An error in the connection can lead to a short circuit or constant operation of the motor.
For clarity, let's look at the main types of contacts and their purpose in the table below. The colors of the wires are given conditionally, since in different refrigerators the wiring can be replaced by previous masters.
| Contact marking | Purpose | Wire color (typical) | Action |
|---|---|---|---|
| 1 (or L) | Network input (Phase) | Red / Brown | Power from socket |
| 2 (or T) | Compressor | Black / Green | Start the engine |
| 3 (or C) | Lamp / Indicator | Orange / White | Light in camera |
| Grounding | Protection | Yellow-green | Safety |
When connecting wires, use high-quality terminals or reliable twisting followed by insulation heat shrink. Avoid areas that may touch the metal body of the refrigerator.
What to do if the colors of the wires do not match the diagram?
In this case, you need to use a multimeter in testing mode. Locate the wire coming from the plug (mains) and the wire going to the compressor. The third wire, as a rule, goes to lighting. Ring the circuit at different positions of the thermostat knob to make sure the contacts are open.
Installing the capillary tube and setting
After the electrical connection, you must correctly position the capillary tube of the new thermostat RKT 2. It should fit snugly against the evaporator in the place where the old tube was located. Often a special clamp or aluminum plate is used for fixation.
Insufficient contact of the tube with the surface of the evaporator will lead to incorrect temperature readings. The refrigerator will “think” that it is warm inside and will work continuously, causing severe freezing of food.
The temperature regime is adjusted experimentally. Turn the control knob to the middle position and start the refrigerator. After a few hours, check the temperature in the chamber using an external thermometer. If necessary, make adjustments through a special hole in the thermostat housing.
⚠️ Attention: The adjusting screw is located inside the thermostat housing. To access it, you may need to remove a seal or carefully open the casing. Turn the screw with small turns (no more than 1/4 turn at a time), waiting for the mode to stabilize.
Diagnostics of typical installation errors
If after installation RKT 2 the refrigerator behaves inappropriately, repeat diagnostics should be carried out. Often the problems lie not in a defective part, but in installation nuances that were missed in a hurry.
Let's consider the main symptoms and their probable causes. Analysis of these signs will help to quickly localize the malfunction without completely disassembling the unit again.
- 🔊 The compressor hums, but does not start - perhaps the contacts of the start relay and thermostat are mixed up.
- ❄️ The refrigerator does not turn off - the capillary tube is poorly pressed to the evaporator or The differential setting has gone wrong.
- 💡 The lamp in the chamber is constantly on - the contact responsible for opening the lighting circuit when the door is closed is incorrectly connected (if this function is linked to a thermostat).
- 🔌 The machine in the panel knocks out - a short circuit in the place where the wires are twisted or a breakdown of the insulation on the housing.
Can it be used RKT 2 instead of the original thermostat?
Yes, RKT 2 is a universal analogue for many models of refrigerators (Atlant, Indesit, Stinol, etc.). The main condition is the coincidence of dimensions, length of the capillary tube and type of contacts. Before installation, check the markings and parameters with the original product.
Why does the refrigerator work non-stop after replacement?
This indicates that the thermostat does not “feel” the cold. Check the tightness of the capillary tube to the evaporator. It is also possible that there is not enough freon in the system, and the thermostat simply does not receive a signal that the lower temperature limit has been reached.
Is it necessary to defrost the refrigerator before replacing?
Yes, complete defrosting is required. Working with electrical wiring inside a wet or icy enclosure is dangerous. In addition, ice can interfere with the careful installation of the new capillary tube and the removal of protective panels.
How to check the serviceability of the new RKT 2 before installation?
Use a multimeter in dial mode. Close the input and output contacts on the thermostat - the device should beep. If you lower the capillary tube into cold water with ice, the contacts should open (stop ringing), which indicates that the bellows is working properly.