How do I know if my refrigerator thermostat is faulty?

The main function of a thermostat is to control the temperature of a specific place; we find them on the walls of our homes, in our cars, in heaters, and in all our appliances. If this device fails, for example, in our refrigerator, we find ourselves facing problems that can directly affect our food, since it is thanks to the thermostat that it is kept in an ideal environment and in good condition.

Are you wondering about How to tell if my refrigerator thermostat is faulty In the following Oman Hardware article, we'll tell you everything you need to know about this control system component and explain what to do if your thermostat fails. Let's get started!

The thermostat is installed in the same electrical circuit that powers the motor compressor and consists of a capillary tube filled with gas or coolant. One end of this tube is in the thermostat and the other end is in the evaporator or freezer; these two are responsible for detecting temperature changes.

The programmed maximum temperature in the regulator causes the coolant or gas, located inside the capillary tube, to open the thermostat contacts, automatically interrupting the current flow to the motor compressor and shutting it off.

After a certain period of time, and once the temperature has risen sufficiently, the thermostat resumes supplying the motor compressor with electrolytic fluid and restarts operation. The on/off cycle is maintained. Maintaining a stable temperature inside the refrigerator Within predefined parameters in the thermostat.

How does a thermostat work?

Initially, the thermocouple lamp is in contact with the evaporator wall, where evaporation ends. Changes in temperature within the evaporator are detected by the lamp, which in turn causes changes in fluid pressure, leading to expansion or contraction of the diaphragm or bellows of the thermostat.

These expansion and contraction movements are transmitted via a system of levers and springs that maintain system tension. These components form a mechanism that amplifies the blower movements and transmits them to the connectors, causing the motor compressor to engage and disengage when the temperature reaches predetermined maximum and minimum values.

To ensure the refrigerator operates properly, it is recommended to adjust the thermostat correctly. It's worth noting that the thermostat's proper functioning depends not only on the temperature it reads inside the refrigerator, but also on how often the refrigerator door is opened, the outside temperature, the amount of food stored, the stability of the refrigerator's electrical supply voltage, and other factors.

We explain here How to adjust the refrigerator thermostat Correctly, step by step:

1. Like all equipment, the thermostat should come with its own instruction manual, so feel free to take a look at it before you first connect the refrigerator.
2. After determining the ideal temperature for both the freezer and refrigerator compartments and their respective spaces, you should adjust the regulators. For the freezer, which produces dry cold, the recommended temperatures range between -22°C and -4°C. For the lower part of the refrigerator, which produces humid cold, the ideal temperatures are approximately 5 ± 3°C.
3. When first connecting the refrigerator, it is recommended to place the thermostat in the middle of the dial if it is manual, or in the middle of the electronic dial if it is digital. Connect the refrigerator and let it run for a full day before setting the thermostat to your desired temperature.
4. Most thermostat selectors have specific values, generally from 1 to 9, in odd numbers. Therefore, if you want a cooler temperature, you would set the selector to 7 or 9, and when you want a cooler temperature, you would set it to 1 or 3. For normal operating temperatures For the refrigerator, we recommend setting the selector to 5.

Take a close look at how the refrigerator works; if you see that it is freezing and frosting on the freezer walls, the reason for this may be that the temperature of the top section is incorrectly adjusted, i.e., it is too high.

Conversely, if the refrigerator takes a long time to start up, the starting temperature may be higher than 8 degrees Celsius. In these cases, you should consult a professional to check the refrigerator's thermostat or other components that may be causing damage to your appliance.

In this other article about how to adjust a refrigerator thermostat, we explain in detail the process you should follow.

When a refrigerator stops working properly, one of the first things to consider is the thermostat. The thermostat turns the refrigerator's compressor on and off to maintain the cooling temperature; that is, when it reaches its maximum cooling level, the thermostat detects this and instructs the compressor to stop until it stops generating more cold air. On the other hand, if the temperature drops, it's because the compressor is running automatically. So what is the Symptoms that may indicate the presence of Bad thermostat? We'll show you how:

• The compressor never works This means that the refrigerator temperature is not regulated, and therefore the food inside will spoil.
• Never turn off the compressor This results in excessive coldness in the lower part of the refrigerator (where fruits and vegetables are usually stored). In this case, soft drinks, water, and other liquids can freeze due to the extreme cold.
• icing Another issue is excessive ice buildup on the evaporator. This obstructs the water outlets and causes problems with food preservation. In this case, you might be interested in reading this article on how to defrost your refrigerator.

Now that you know how to adjust a refrigerator thermostat and exactly how it works, let's see When should you change it? :

• An open circuit is detected when measuring continuity between the refrigerator's outlet terminals. This, of course, is not something you need to know how to do yourself, as a refrigeration specialist will be responsible for detecting it.
• When the temperature changer is very hard or you feel that it is broken inside and is free, it rotates in several directions.
• When it stops cooling or causes ice to form all over the refrigerator. However, it should be remembered that the refrigerator clock (or timer) has an automatic shut-off function from time to time (generally programmed to shut off every 8 hours) to start the compressor again afterward (about 20 minutes off).
• If you measure the thermostat using a test device, this gives you a false reading.

when Thermostat measurement Using a testing device, multimeter, or test tool, you should perform the following steps:

1. Turn off the thermostat in the refrigerator.
2. Set the thermostat knob to the coldest setting, i.e., 9.
3. Set the test device to the ohmmeter or continuity test option.
4. Measure using test leads on the thermostat terminals. The tester must determine continuity; that is, the indicator should show zero, whether analog or digital. If there is no continuity, the thermostat will need to be replaced.
5. Perform the steps mentioned above, but now place the thermostat knob at the lowest level, i.e., at 1.
6. The lab should mark the reading with infinity. If it doesn't, you'll need to replace the thermostat.

If the timer fails, the refrigerator will exhibit symptoms like those mentioned above. However, a qualified technician will be the one who can identify the specific component causing the problem.