Thermistor or NTC sensor in refrigerator
In modern electronically controlled refrigerators, it is found that, instead of an analog thermostat, they are now replaced by small digital temperature sensors known as thermistors or NTC sensors. These electronic sensors are also widely used in other appliances, they are also used especially in washing machines. The use of these devices is increasing and are used mostly in domestic and industrial washing machines and kitchens.
Refrigeration thermistors are of two basic types, NTC and PTC.
Cooling temperature sensor. If the resistance increases as the temperature rises, the device is called a Positive Temperature Coefficient (PTC) or POSISTOR and can be found at the beginning of the compressor.
If the resistance increases with the decrease in temperature, the device is called negative temperature thermistor (NTC). These are used in temperature control of freezer and food preservative.
The use of NTC sensors or thermistors in refrigerators
The reason for using these devices is very simple, they are cheaper and more accurate than the older analogue thermostats and allow a much greater control because they read a range of temperatures as opposed to the specific predeterminations found in the old thermostats used in refrigerators.
How to Test the Refrigerator Thermistor
How to test a refrigerator temperature sensor:
It should be noted that, although in some devices these fail regularly, as in some brands of refrigerators ... it should be mentioned that these small appliances are very reliable in our experience.
We are often asked if they are the main cause of machinery breakdowns, but before we know that several times they are not responsible for the defects, so we must measure them and check if they are good. Fortunately, they are easy to check to find out if they are faulty.
It should be noted that the resistance values can vary considerably from one apparatus to another and therefore it is not possible to determine the value to be sought in general. In fact, in many cases, even in the "service".
However, this is not important in many ways when you test whether a thermistor is faulty or not.
If the resistance changes, it is likely that the thermistor is good. Obviously, this is not always the case, but 99% of the time will be true.
If the resistance does not change, it is likely that the thermistor is faulty. Again, of course, this is not always the case, but it will be almost all the time.
Although this is a quick and inadequate way to test a thermistor, it works and it's fast.
Refrigerator and freezer with electronic card
In most refrigerators that use thermistors, and with some notable exceptions, it is much more likely that the electronic control board fails rather than the thermistor, so there are a few things to check before exchanging this.
Make sure the connections are good and cleaned on the card, if they are not, this can cause all sorts of strange errors. Remember that as the electronic board reads the resistors, anything that could change this reading will cause a problem.
If possible, check the refrigerator card
Refrigerator Electronic Card Make sure that the problem is not caused by the thermistor, as it may cause a false reading or block the correct reading.
Defrost the refrigerator completely and restart, as I have always mentioned, for a few days, leaving the doors open, so there is no ice buildup that allows the sensors to read incorrect values, especially in a fridge.
If all goes well and tests outside the thermistor are correct, the defrost system is likely to be faulty or defective.
Electronic panels, control panels and thermistors for domestic refrigerators, refrigerators and freezers are available in our personalized service that we provide. If you do not find what you are looking for, feel free to ask us.
As always, if you are not professionally ready to do this job, do not try to repair it yourself. This could cause injury or personal injury to persons using the equipment.
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