Modern refrigerators LG are famous for their reliability, but even the most advanced equipment has failures in the cooling system. If you notice that the unit has stopped freezing or, conversely, has begun to freeze food to the point of stone, the first thing suspicion falls on is the thermostat. Understanding where the thermostat is located in an LG refrigerator is critical for initial diagnosis and possible self-repair.
In most cases, the problem lies not in the compressor itself, but in the sensors that give it incorrect signals. The location of this element directly depends on the control system: whether it is mechanical or electronic. In older models, you will look for a rotary knob, and in new ones, you will look for hidden sensors inside the cameras.
Before disassembling the equipment, you need to clearly determine the type of device you have. The algorithm of actions and the set of tools that you will need depend on this. Incorrectly determining the type of control can lead to you looking for a non-existent part in the wrong place, wasting time and risking damage to the integrity of the case.
Differences between mechanical and electronic controls
The fundamental difference lies in the principle of operation of the temperature control system. Classic mechanically controlled models use a physical thermostat, which is a capsule of gas or liquid connected to a long capillary tube. When the temperature in the chamber changes, the pressure inside the capsule changes, opening or closing electrical contacts.
In models with a system No Frost and electronic control, thermistors play the role of a mechanical thermostat. These are semiconductor elements whose resistance varies depending on the ambient temperature. They have no moving parts and transmit digital data to the main control board.
It is easy to visually distinguish these systems. If there is a rotary knob on the front panel or inside the refrigerator compartment with divisions from 1 to 7 or from Min to Max, you have a mechanic. If the temperature is set by buttons or a sensor with degrees displayed on the display, you have electronics in front of you.
⚠️ Attention: Trying to find a mechanical thermostat in an electronically controlled refrigerator is pointless. In such models, it does not physically exist, and its functions are distributed between several sensors and ( - main control board).
Understanding this difference saves hours of futile searches. In electronic models, a “thermostat” is conventionally called a temperature sensor, which can be located in completely different places, often hidden behind plastic panels.
Thermostat location in models with mechanical control
If your refrigerator LG is a classic type with a drip defrosting system and mechanical adjustment, search for parts will be the simplest. In such devices, the thermostat is usually located inside the refrigerator compartment. Most often, it is hidden in a special plastic casing, which can also serve as a lampshade for a lighting lamp.
To get to it, it is often enough to simply remove the protective cap. In some modifications, the thermostat is hidden behind the top panel inside the chamber. To access it, you will need to carefully pry up the plastic plug or unscrew several screws holding the cover.
It passes through the entire inner wall of the chamber and is attached to the evaporator. It is this tube that reads the temperature, so when dismantling you need to act extremely carefully so as not to bend or damage it.
- 🔍 Look for the temperature adjustment knob inside the chamber on the side wall or under the ceiling.
- 🔧 For removal, you may need a Phillips screwdriver and a flat spatula for plastic latches.
- ❄️ The capillary tube is very fragile, avoid sudden movements when removing the unit.
Sometimes manufacturers hide the thermostat behind a decorative strip above the door. In this case, it is necessary to open the door and inspect the upper end of the refrigerator body. Removing this bar usually requires unscrewing screws that are accessible only when the door is open.
Where to look for temperature sensors in No Frost refrigerators
In units equipped with a system No Frost, the situation is radically different. There is no single central thermostat in the usual sense. The temperature regime is controlled by a network of sensors scattered across different nodes. The main ones are located in the freezer compartment, since this is where the air is cooled, which then circulates throughout the refrigerator.
Most often, the main sensor responsible for turning the compressor on and off is located in the evaporator area. To get to it, you will have to dismantle the back wall of the freezer. This is a more complex procedure that requires defrosting the unit within 10-12 hours.
Additional sensors can be built into the air duct connecting the freezer and refrigerator compartments, as well as in the ventilation zone. In some models LG one of the sensors is located at the very bottom of the refrigeration chamber, capturing the temperature of the descending cold air.
Why are there so many sensors?
In the No Frost system, it is critical to monitor not only the overall temperature, but also the moment the evaporator begins defrosting, the temperature of the air leaving the fan and the temperature at the coldest point. This prevents the formation of ice plugs in the channels.
If the refrigerator has stopped cooling, but the compressor is constantly humming, the problem may be with the defrost sensor. If it does not turn on at all, most likely the main thermistor or control unit has failed. Localization of the fault is possible only by testing each element with a multimeter.
Algorithm for searching and accessing the thermostat
The search and replacement process requires consistency. Random unscrewing of the bolts can lead to breakage of the plastic fasteners, which become very fragile in the cold. Always start by disconnecting the device from the power supply.
The first step is a visual inspection. If you have a mechanical model, locate where the capillary tube enters the housing. If electronic, study the layout of the sensors for your specific model LG, since they may differ even within the same series.
To access the insides of the fridge compartment with a mechanical thermostat:
- Empty the chamber of products.
- Remove the shelves and drawers, interfering with access to the ceiling or side wall.
- Carefully pry up the plastic lamp shade (if the thermostat is under it).
- Unscrew the screws securing the thermostat housing.
In models No Frost the algorithm is more complicated. It is necessary to completely defrost the freezer, remove all the drawers, unscrew the screws on the back wall and carefully unclip the plastic clips. Only after opening the evaporator, you will see sensors attached to it or close to it.
☑️ Preparation for disassembly
Do not forget that plastic loses its elasticity at low temperatures. If you've just defrosted your refrigerator, let it sit at room temperature for at least 30 to 40 minutes before you begin to undo the latches. This will reduce the risk of housing breakage.
Diagnostics of thermostat and sensor malfunctions
It is possible to understand that a thermostat or sensor is faulty by indirect signs, but an accurate diagnosis can only be made by the device. The main diagnostic tool is a multimeter switched to resistance measurement mode (Ohm).
For a mechanical thermostat, the test is simple: in a warm state, the contacts must be closed (resistance is close to zero). If you place the sensitive part of the thermostat in the cold (for example, in the freezer for 15 minutes), the contacts should open and the resistance becomes infinite.
With electronic sensors (thermistors), the process is slightly different. Their resistance changes smoothly. At room temperature (about 20-25°C) it is usually 5-10 kOhm (the value depends on the model). As it cools, the resistance should increase. If the multimeter shows a break or zero, the sensor is faulty.
⚠️ Attention: Never test sensors under voltage! Resistance measurements are carried out only with the refrigerator disconnected from the network. Applying voltage in Ohm measurement mode will instantly disable the multimeter.
It is also worth paying attention to the condition of the wires going to the sensor. Under conditions of vibration and temperature changes, the insulation may fray and the contacts may oxidize. Often the problem lies not in the sensor itself, but in poor contact in the connector.
Table of symptoms and possible causes
To simplify diagnosis, you can use the summary table. It will help narrow down the search for a malfunction by linking visible symptoms with probable problems in the thermoregulation system.
| Symptom | Probable cause | Where to look for the problem | Actions |
|---|---|---|---|
| The refrigerator does not turn on, there is no light | Open thermostat circuit | Mechanical thermostat or wiring | Ring the thermostat, check the power supply |
| Constant operation of the compressor, ice in camera | Stuck contacts / Sensor malfunction | Thermostat / Evaporator sensor | Replace thermostat or sensor |
| Short operating cycles (on/off) | Incorrect sensor readings | Air sensor in the chamber | Check the sensor resistance |
| Error on the display (Er FF, Er SF) | Sensor malfunction or fan | Freezer compartment, evaporator | Diagnostics by error code |
Error codes such as Er FF or Er SFoften indicate problems in the freezer compartment, where and the key elements of the system are located No Frost. Decoding the code is the first step to understanding which sensor requires replacement.
The nuances of replacing and setting up a new thermostat
If diagnostics have confirmed a malfunction, it is necessary replacement. For mechanical thermostats, it is important to choose an analogue with identical parameters: capillary length, on/off temperature and type of contacts. Universal models may not work correctly, causing frequent switching on or insufficient cooling.
When installing a new mechanical thermostat, the capillary tube must be laid in exactly the same way as the old one was laid. Bends must be smooth, with a radius of at least 50 mm. A crease in the tube will lead to freon leaking from the bellows and repeated breakdown.
In electronic models LG sensors often have unique connectors. When purchasing a new part, make sure that the wire length and connector type match. Extended wires can create additional resistance, which will throw off the calibration of the system.
- 🛠️ Use heat shrink to insulate the joints of the wires.
- 🧊 Before assembling, make sure that all door seals lie flat.
- 🔌 After replacing the electronics, let the refrigerator work for several hours without loading food.
After replacing the mechanical thermostat, adjustment may be required. The body of the new element sometimes has screws under the seal, which allow you to adjust the temperature range. However, it is not recommended to do this without special equipment - it is better to immediately install the factory part.
Is it possible to temporarily close the thermostat contacts?
Yes, in emergency cases, in order to get to the store for a spare part, you can close the contacts of a mechanical thermostat. This will force the compressor to run constantly. However, you cannot leave the refrigerator in this mode for a long time: the evaporator will become covered with ice, the food in the refrigerator compartment may freeze, and the compressor will burn out from overheating due to the lack of rest cycles.
Why does the refrigerator operate jerkily after replacing the sensor?
This may be due to incorrect positioning of the new sensor. If it does not fit tightly to the surface of the evaporator or air duct, it will be delayed in reading the temperature. It is also possible that the resistance of the new sensor is incompatible with the control board algorithms.
How to reset the error on the LG display?
Most often, it is enough to disconnect the refrigerator from the network for 10-15 minutes. If the error persists, then the problem has not gone away. Some models require entering the service menu using a combination of buttons, but for the average user it is safer to simply reboot the device.
Where to buy an original thermostat for LG?
It is better to look for original spare parts in authorized service centers or specialized stores of spare parts for household appliances, indicating the exact model (P-code) of your refrigerator. Chinese analogues can work, but their service life is often lower.
Repairing the thermoregulation system is a task that requires care and accuracy. Knowing where the thermostat is located in your LG refrigerator and how it works will help you quickly diagnose the problem. However, if you are not confident in your abilities, especially when working with the system No Frost, it is better to entrust complex disassembly to professionals so as not to damage fragile plastic or the freon circulation system.