Thermostat for the refrigerator: device, check + details of replacement if necessary

It is difficult to imagine your life without household appliances.There are devices that we could do without, and there are those without which the arrangement of a living space is quite rightly considered incomplete. One of these vital items is the refrigerator. Do you agree?

Do-it-yourself repair of household appliances is a good help for the family budget. If desired, you can master many repair operations. For example, replacing a refrigerator thermostat is not that difficult. You just have to understand the design features and operating principles of the device.

We will tell you how to detect a faulty thermostat. The article we have proposed describes in detail how it is replaced during the repair of a Stinol brand refrigerator. The information is accompanied by a thematic selection of photo and video materials with expert advice.

Design features and operating principle

The thermostat or thermostat is one of the main elements without which normal operation of the refrigerator is impossible. It records the readings of temperature sensors in the refrigerator and freezer compartments and sends a signal to the compressor start relay.

In accordance with these signals, the compressor turns on if the chamber is not cold enough and turns off when the temperature reaches a set level.Technically, the thermostat is a relay, at one end of which there is a sealed tube filled with freon.

On the other side there are contacts, the opening and connection of which sends a signal to the compressor. The end of the tube with freon, also called a capillary tube, is fixed to the evaporator.

The refrigerant placed inside reacts sensitively to heating and cooling. When the temperature decreases or increases, the pressure level inside the tube changes, causing the relay contacts to connect or open.

The movement of the contacts is controlled by a small spring. It is used to set the temperature level that should be inside the refrigerator compartment. A temperature adjustment knob is attached to the spring. Turning this knob changes the tension of the spring.

As a result, more or less force must be applied to close and open the contacts. This affects the level of pressure in the capillary tube at which the contacts are triggered.

A thermostat is a small device that is equipped with a sealed tube with a sensor filled with refrigerant. Based on changes in evaporator temperature, the relay turns the compressor on or off

This regulates the degree of cooling of the air in the refrigerator. When using an electronic regulator, this process is carried out slightly differently, but the principle remains approximately the same: the desired temperature level is set based on the actual indicators recorded by the capillary tube.

But such models use an electronic control module that can simultaneously manage data from several sensors.It is not always possible to repair or replace such a thermostat at home. Handling complex electronics requires knowledge and special equipment.

Typically, the thermostat is installed inside or outside the refrigerator compartment. Before starting repairs, it wouldn’t hurt to study refrigerator device and technical data sheet of the device. There may be a lot of useful information on the design of a specific thermostat model, as well as its location.

Usually the thermostat is located next to the handle for setting the temperature. The internal arrangement is typical for relatively old models. Inside the camera, the element is usually enclosed in a plastic protective housing.

The adjustment knob is located directly on it. To remove the thermal relay, you need to remove this handle and unscrew the mounting screws to remove the housing.

In more modern models, the thermal relay is placed outside the chamber in order to save precious cubic centimeters of internal space and not spoil the design with additional elements

But you also need to look for the thermostat near the control knob, usually under the refrigerator body somewhere at the top. The handle is removed in the same way, the fasteners are unscrewed and what you are looking for is found behind the protective panel.

Ways to detect the problem

If the thermostat breaks, this does not mean that the entire refrigeration unit will immediately stop working. But the lack of correct information about the current temperature will affect its operation.

Option #1 - check the functioning of the equipment

Symptoms of incorrect operation of refrigeration equipment may be as follows:

• the compressor operates without interruptions or with very short and rare interruptions;
• the temperature inside the refrigerator chamber drops to zero, and sometimes even lower;
• a large amount of frost or even ice appears on the walls;
• It's too warm inside the refrigerator;
• The refrigerator does not turn on after being turned off, etc.

Of course, these signs can be associated not only with breakdowns of the thermal relay, but also with malfunctions of other elements.

In order to correctly determine the cause of problems identified during the operation of a household refrigerator, you will need to carry out a little diagnostics. You can do this yourself

Option #2 - diagnostics using a thermometer

To do this, you need to completely disconnect the refrigerator from the power supply, and then completely defrost it in accordance with the instructions. Of course, the contents will have to be removed.

After this, you need to turn on the device and move the thermostat knob to the position that will allow you to get the lowest possible temperature. If your refrigerator model has a freezing mode, it is recommended to use it.

To test the operation of the thermostat, you need to empty the refrigerator of all food, place a thermometer inside the chamber and check its readings after a few hours

In the refrigerator compartment, approximately in the middle, you need to place a thermometer designed to measure air temperature. It is better to use a device that allows you to take measurements below zero. The refrigerator is left in this mode for about two hours. After this, you need to check the thermometer readings.

If the temperature in the refrigerator compartment has dropped to about six degrees by this time, there is no problem with the thermostat. But when the inside becomes noticeably warmer or colder than this level, the thermostat will have to be replaced.

Option #3 - visual inspection of the refrigerator chamber

If after defrosting A so-called snow cap forms very quickly inside the chamber; initial diagnostics of the health of the thermostat can be performed very simply.

The appearance of a snow coat in the refrigerator compartment almost always means that the thermostat is not working correctly; you need to diagnose its condition

To do this, when the compressor is operating, the adjustment knob begins to be turned in the direction of increasing the temperature inside the chamber. If the relay is working properly, at a certain moment the sensors will record the desired temperature level, after which the compressor will turn off. If the engine continues to run, the thermostat needs to be changed.

After such diagnostics and if the thermal relay is working, it is recommended to remove all contents from the chamber and allow the device to run idle for about six hours. During this period, you need to pay attention to the duration of breaks in the operation of the compressor.

If it is about 40 minutes, everything is fine, you can use the refrigerator as usual. If the compressor turns on too often or infrequently, you should try to adjust this moment using the relay settings. If this fails, you will most likely have to install a new thermostat.

Rules for dismantling the thermal relay

If the refrigerator does not turn on at all, it will be impossible to carry out the diagnostics described above. The probable cause of the breakdown is an electrical failure of this element.

But it can also be a problem compressor malfunction, for example, a burnt out motor winding. To determine whether the thermostat needs to be replaced, it will have to be removed from the refrigerator for examination.

Typically, the thermostat is located next to the control knob, which is used to set the air temperature in the refrigerator compartment.Double-chamber models are equipped with a set of two such handles

First you need to unplug the refrigerator. Now you should find the place where it is located, as described earlier. Usually you need to remove the adjustment knob, remove the fasteners and remove the protective elements.

Then you need to carefully inspect the device, paying close attention to the wires through which the power is supplied.

All of them have different color markings depending on their purpose. Typically, a yellow wire with a green stripe is used for grounding. This cable should be left alone, but all the others should be disconnected and shorted together.

Now the refrigerator is plugged in again. If the device still does not turn on, the thermostat is probably working properly, but there are serious problems with the compressor.

If the refrigerator does not turn on at all, the cause may be not only a malfunction of the thermostat, but also a breakdown of the compressor, for example, a burnt-out motor winding

If the engine starts working, we can clearly conclude that the relay needs to be replaced. Before starting work, it doesn’t hurt to arm yourself with a smartphone or camera in order to consistently record all operations. When installing a new thermostat, these pictures can be very helpful, especially for beginners.

You need to clearly remember which cable core was used for what purpose. Typically, a black, orange or red wire is used to connect the thermal relay to the electric motor. A brown wire leads to zero, a yellow-green wire provides grounding, and a pure yellow, white or green wire is connected to an indicator light.

To connect the thermal relay, wires with different color markings are used; you need to remember the purpose of each wire so as not to get confused during reassembly

Sometimes removing a damaged regulator can be difficult, especially when it is placed outdoors. For example, in some Atlant refrigerator models you have to completely remove the chamber door from its hinges. To do this, you need to remove the trim that is installed above the top hinge and unscrew the bolts hidden under it.

Before removing the adjustment knob, you also have to remove the plugs and unscrew the fasteners. All these operations must be done carefully. It is better to store fasteners and linings in a small container so that they do not get lost. The thermostat itself is usually screwed to the bracket; it must be carefully removed, unfastened and removed.

If the thermostat is located inside the refrigerator compartment, it is usually hidden under a plastic casing, where a lamp for illumination can also be mounted

A new thermostat is installed in its place, following the reverse assembly order. Sometimes the breakdown of the thermostat is associated with a malfunction of the so-called capillary tube or bellows. If you replace only this element, the relay can be left.

To perform this procedure, you will have to remove the thermal relay, following the method described above. The bellows must be disconnected from the evaporator and carefully removed from the device body. Now a new capillary tube is installed, connected to the evaporator, and the relay is mounted in its original place, and the disconnected wires are connected.

Replacement using the example of a Stinol refrigerator

For Stinol refrigerators Relay failure is a fairly common occurrence, especially after five to seven years of operation.

Most often, the bellows tube fails here, since this is the option provided by the manufacturer of this element. The Stinol-101 ​​model has only one compressor, but the Stinol-103 has two: separately for the refrigeration and freezer compartments.

This is a contact diagram for a K-59 type thermal relay, which allows you to get an idea of ​​which wires should be connected where. Color markings may vary; a photo on your phone will help you save the information; you can also draw a similar diagram yourself

The automation of different models is slightly different, which is reflected in the corresponding electrical diagrams, but otherwise these refrigerators are very similar, so it makes sense to consider the procedure for repairing them at the same time.

To understand that the Stinol refrigerator needs repair or replacement of the thermostat, you need to pay attention to the following signs:

• the compressor runs non-stop and does not respond when the regulator is set to OFF;
• when moving the adjustment knob to the OFF mark, there is no characteristic click;
• the temperature in the refrigerator chambers noticeably exceeds the parameters set during adjustment.

The Stinol-103 refrigeration chamber uses a K-59 thermal relay; it is easy to check the markings, they are indicated on the body. To remove the adjustment knobs, you need to use a thin awl. You just need to pry them up and remove them. The Stinol-101 ​​model has only one adjustment knob, while the Stinol-103 has two, one for each compressor.

To remove the adjustment knob of the Stinol refrigerator (1), you need to use some sharp object, for example an awl.Then remove the decorative trim (2), which is held in place by four protrusions

After the handle is removed, you need to remove the decorative trim, which has six protrusions. This is a fragile item and must be handled with care to avoid damaging it. There are nuts under the cover that need to be unscrewed. After this, you need to unscrew the screws that secure the control panel.

Under the decorative trim there are mounting screws (1) that hold the thermal relay in the correct position; they must be unscrewed to continue dismantling the element

It is best to remove the screws holding the refrigerator door hinge last. To avoid possible damage, the door must be held. Now you can lift the panel and remove the door from its hinges.

The next step is to remove the top cover of the refrigerator.

The fasteners that secure the control panel and door hinge (1) of the Stinol refrigerator must be unscrewed, moving towards the door, and not away from it

The necessary fasteners are located on the rear side. They are unscrewed and the cover is removed. This will give you free access to the thermostat.

First you need to disconnect the relay contact connectors, after which you can remove the element from the refrigerator control panel.

After the doors and top panel of the Stinol refrigerator have been removed, you can carefully remove the thermal relay for inspection and diagnostics

At this stage, you need to remember or write down the color coding of the individual wires. To remove a worn capillary tube, remove the plastic cover.

Now you need to unscrew the fixing screw and remove the lighting unit. The tube is removed through the hole provided for this purpose.

To continue replacing the thermostat in the Stinol refrigerator, you need to remove the cover (1) in the refrigerator compartment and remove the capillary tube (2)

The new element is installed in such a way that the uninsulated area in its lower part is securely hidden under the overlay. The hole is closed with a plastic plug to restore the seal of the chamber.

Usually the capillary tube protrudes beyond the thermostat. It must be carefully placed under the top lid of the refrigerator; there is enough space there.

To remove the capillary tube (2) and replace it, you first need to disconnect the lighting unit, which is secured with a screw recessed into its housing

Now you need to reassemble the thermostat and the refrigerator: connect all the necessary connections, install and secure the refrigerator lid, and hang the door.

And again, screwing the door hinge fasteners is done last, when other similar screws are already installed.

The hole that appears on the rear panel during repair work should be sealed with plastic to restore the tightness of the refrigerator compartment

To check the condition of the Stinol refrigerator thermostat at home, you can use simple diagnostics. Contacts 3 and 4 of such a device should remain closed at room temperature.

If, after connecting them with a jumper, the compressor turns on, the thermal relay is faulty and needs to be replaced. If the thermostat settings are lost, they can be corrected by turning the adjusting screws, but this should be done in a service center that has the necessary equipment.

An equally important functional unit in the design of the refrigerator is start relay, the device, purpose and repair methods of which will be introduced in our recommended article.

Conclusions and useful video on the topic

The process of replacing the thermostat is clearly demonstrated in the following video, in which the master shares the nuances of repairing Stinol-type refrigeration equipment:

Interesting tips for diagnosing the condition of the relay and replacing it using the example of two models of refrigerators are contained in this video:

The procedure for replacing a thermostat cannot be called too complicated. However, if you mishandle this element, you can only worsen the situation. A detailed study of the repair procedure and attention to detail will help restore the functionality of the refrigerator.

Tell us about how you selected a thermostat to restore the functionality of the refrigerator. Share useful information and valuable information on the topic of the article that can be useful to site visitors. Please leave comments, post photos and ask questions in the block below.