A modern refrigerator has ceased to be just a metal box with ice, turning into a complex unit where each element plays its role. One of the key parts in models with the system No Frost is a tubular electric heater, which is often simply called a heating element. It is this small but important component that is responsible for the normal functioning of the defrost system, preventing the formation of ice plugs in the air ducts.
When users are faced with the fact that the freezer stops freezing and a layer of ice is visible on the back wall, most often suspicion falls on the compressor or thermostat. However, in most cases, defrosting becomes the cause. Understanding the principle of its operation will help you quickly diagnose the problem and avoid an expensive call to the technician. faulty heater defrost. Understanding how it works will help you diagnose the problem faster and avoid an expensive call to the technician.
In this article we will analyze in detail the design of the heating element, consider the main symptoms of its failure and provide step-by-step instructions for diagnosis and replacement. You will learn how to safely carry out repairs with your own hands and what to pay special attention to when assembling the unit.
The principle of operation of the heater in the No Frost system
System No Frost (literally “no frost”) implies forced air circulation inside the refrigerator chambers. During operation, condensation inevitably forms on the evaporator, which is located behind the rear panel, turning into ice. If this ice is not removed, it will completely block the air channels, and the cold will stop flowing into the chamber.
To solve this problem, a defrost cycleis built into the design. Periodically, at certain intervals (usually every 8-12 hours), a timer or electronic control module gives a command to turn on the heating element. The heating element begins to generate heat, melting the ice crust on the evaporator.
The resulting water flows down a groove into a special tray located above the compressor, where it safely evaporates. It is important to note that the heating element does not operate constantly, but only in defrost mode, so its resource is quite long, but not infinite.
⚠️ Attention: the defrosting heating element is turned on only when the compressor is turned off. Simultaneous operation of the heater and motor-compressor is structurally impossible and will lead to network overload.
In some models of refrigerators, such as Indesit or Atlant, several heating elements can be used: one for the evaporator, the other for the drainage chute, so that the water does not freeze on the way. This makes the system more reliable, but complicates diagnostics, since any of them can fail.
Main signs of a heating element malfunction
You can determine that the heating element has stopped performing its functions by a number of characteristic signs. Ignoring these symptoms can lead to more serious damage, including compressor failure due to constant operation without stopping.
The first and most noticeable sign is Ice freezing on the back wall of the freezer or in the niche where the evaporator is located. Ice can coat the food, the door, and even prevent it from closing properly. This indicates that the defrost system does not start or cannot cope with the amount of ice.
- 🧊 Ice coat: A thick layer of frost or ice on the evaporator, visible when removing the back panel.
- 🔊 Continuous operation: Compressor hums continuously, trying to compensate for the lack of cooling capacity due to clogged air ducts.
- 💧 Water on the floor: Melted water can flow out from under the door if the drainage hole is clogged with ice that has not melted.
- 🌡️ Increase in temperature: The refrigerator compartment becomes warmer, food begins to deteriorate, although the thermostat is set to maximum.
Another indirect sign may be the absence of the characteristic “gurgling” or crackling sound, which is usually heard when the defrost system is operating. If your refrigerator used to make such sounds, but now stands absolutely silent during periods of supposed defrosting, this is a reason to check.
⚠️ Attention: Do not try to chip the ice with a knife or sharp objects. You can damage not only the heating element, but also the evaporator tubes, which will lead to a freon leak and expensive repairs.
Types of heating elements and their location
Structurally, heating elements may vary depending on the model and manufacturer of refrigeration equipment. Understanding what type is installed in your unit will help you choose the right replacement part.
The most common option is open heating element, which is a curved metal tube located directly under the evaporator. It heats the air that passes through the radiator, melting the ice. Such elements are often found in models Samsung and LG.
The second type is a drainage gutter heater. It is a flexible insulated wire or a small tube laid along the water drainage channel. Its task is to prevent water from freezing in a narrow hole, creating an ice plug. Some models Bosch and Siemens use a combined heater covering the entire evaporator area.
| Heating element type | Location | Function | Frequency of breakdowns |
|---|---|---|---|
| Open (tubular) | Under the evaporator | Main radiator defrost | High |
| Drainage | In the drain channel | Prevention of drain freezing | Medium |
| Glass (ceramic) | Inside the case | Safe air heating | Low |
| Aluminium | On the surface of the evaporator | Fast heat transfer | Medium |
It is worth noting that modern models are increasingly equipped with glass heaterswhich are considered safer and more durable, since they do not oxidize and are less susceptible to mechanical damage during installation.
Why does the heating element burn out?
The main reason is the natural nichrome spiral inside the tube. Over time, the metal becomes thinner and breaks. The second reason is moisture getting on the contacts or corrosion of the housing, which leads to a short circuit. In rare cases, poor-quality voltage in the network is to blame.
Diagnostics and testing with a multimeter
Before going to the store for a new part, you need to make sure that the problem is in the heating element. Often the symptoms may coincide with a malfunction of the defrost timer, defrost sensor or fuse.
You will need a multimeter to carry out diagnostics. First, you need to remove the back panel of the freezer, after defrosting the refrigerator for 24 hours. Only after complete removal of the ice can you begin visual inspections and dialing.
A visually serviceable heating element should not have swelling, ruptures or traces of burning. However, often the defect is not visible to the eye, so instrumental control is necessary. Switch the multimeter to resistance measurement mode (Ohm).
- 🔌 Checking the contacts: Attach the probes to the terminals of the heating element. The device should show resistance in the range from 200 to 600 Ohms (the exact value depends on the power).
- ❌ Open circuit: If one or infinity is displayed on the multimeter screen, it means that the spiral inside is burned out and the part requires replacement.
- ⚡ Checking for breakdown: Attach one probe to the terminal, and the second to the metal body of the heating element. The device should not show anything (infinity). If there is a reading, it means there is a breakdown in the body, which is dangerous.
It is also important to check the defrost temperature sensor, which is in the chain with the heater. At room temperature it should “ring” (show resistance), and when cooled, it should open the circuit. If the sensor is faulty, it may not give a command to turn on the heating element, even if the heater itself is intact.
⚠️ Attention: When checking with a multimeter, make sure that the refrigerator is unplugged from the outlet. Measuring resistance under voltage will damage the device.
☑️ Tools for replacement
Step-by-step instructions for replacing the heating element
Replacing the heating element is a procedure of medium complexity that requires care and attention. If you are confident with tools and follow safety precautions, you can perform this repair yourself.
Start by completely defrosting the refrigerator. Leave it turned off for at least 24 hours to allow all the ice inside to melt. You can speed up the process with a hairdryer, but be careful not to melt the plastic elements of the case.
Remove all shelves and drawers from the freezer. Then remove the rear plastic panel covering the evaporator. It is usually secured with several screws and plastic latches. Proceed with care, plastic becomes brittle in the cold.
After accessing the evaporator, find the heating element. It can be mounted on special brackets or simply lie in the grooves. Disconnect the power wires, having previously photographed the connection diagram so as not to confuse the contacts during assembly.
Sequence of actions:1. Turn off the power.
2. Remove the panel.
3. Disconnect the heating element.
4. Extract the old element.
5. Install a new one.
6. Connect the wires.
7. Reassemble in reverse order.
Install a new heating element in place of the old one. Make sure it fits snugly and does not touch any plastic parts that could melt when heated. Connect the connectors, check the reliability of the contacts.
Assemble the structure in reverse order: install the panel, return the shelves and drawers. Plug in the refrigerator. The first few cycles of operation may be accompanied by the smell of burning dust from the new heating element - this is normal.
Frequently asked questions and answers
Is it possible to operate a refrigerator without a heating element?
Theoretically, you can start the unit, but this will lead to rapid fouling of the evaporator with ice. After 2-3 days, the air circulation will stop, the compressor will work without stopping, and the temperature in the chambers will rise. This will lead to spoilage of products and breakdown of the compressor.
Why does a new heating element burn out after a short time?
A common reason is a malfunction of the defrost sensor or timer. If the sensor is “stuck” in a closed state, the heating element can heat constantly, even when there is no need for it, which leads to its overheating and combustion. It is also worth checking the wiring for chafing.
How much does it cost to replace a heating element with a specialist?
The cost consists of the price of the spare part itself and the work of a specialist. On average, taking into account on-site and diagnostics, repairs will cost 20-30% of the cost of a new refrigerator. Replacing it yourself allows you to save on work.
How to extend the life of the heating element?
Regularly defrost the refrigerator (even the No Frost system) if you are leaving for a long time. Monitor the condition of the door seals: if they allow warm air to pass through, the load on the defrosting system increases, and the ice freezes faster.