The situation when the refrigerator stops defrosting on its own, often taking owners by surprise. A “coat” of ice builds up in the chamber, the food freezes to the walls, and the unit works almost without interruption, trying to maintain the set temperature. In most cases, especially in models with the No Frost system, the culprit of such problems is a failed heating element, which in technical documentation is often abbreviated as heating element. If this unit stops turning on, the evaporator becomes overgrown with ice, blocking the air circulation.
Before calling a technician or buying expensive spare parts, it makes sense to conduct independent diagnostics. Checking the heating element is one of the most accessible procedures within household repair, which does not require deep knowledge of electrical engineering, but requires accuracy and the availability of basic tools. Understanding exactly how the test takes place will allow you to save a significant amount and time, as well as accurately determine whether a part needs to be replaced or the problem lies in the control electronics.
In this article we will analyze in detail the algorithm of actions necessary for accurate diagnosis of the heater. You will learn how to safely get to the part, which resistance values are considered normal, and which indicate a breakdown or open circuit. We will also consider indirect signs of malfunction, which can appear long before the complete failure of the defrost system.
Symptoms and signs of heater malfunction
The first stage of diagnosis is always a visual inspection and analysis of the behavior of the refrigeration equipment. The absence of cold or the presence of ice does not always indicate a burnt heating element. However, there are a number of characteristic symptoms that most likely indicate problems in the defrost circuit. If you observe the phenomena listed below, the probability of failure of heating coil or supply wires is more than 80%.
Pay attention to the operating mode of the compressor. In a working refrigerator, cooling and idle cycles alternate regularly. If the engine hums almost non-stop, trying to compensate for the loss of cold, this is an alarming signal. An ice plug on the evaporator, caused by a non-working heating element, blocks the airflow, and the temperature sensors record “heat”, causing the compressor to wear out.
In addition, it is worth listening to the sounds made by the unit. Sometimes when you try to start defrosting (usually this happens at certain intervals), you can hear a relay click, but there is no characteristic hissing or crackling sound of melting ice. In models with an open evaporator arrangement (after removing the back panel), a thick layer of frost is visually visible, which does not melt even after a long period of inactivity.
⚠️ Attention: Operating a refrigerator with a defrosting system that is not working leads to rapid wear of the compressor. Do not ignore the first signs of icing, as repairing the motor will cost much more than replacing the heating element.
Necessary tools and safety measures
To carry out high-quality diagnostics, you will need a minimum set of tools, which any home craftsman usually has. The key device is multimeter (tester), capable of measuring resistance (Ohm) and checking the integrity of the circuit (testing mode). Without this device, the check will be only tentative, since it is impossible to visually determine the integrity of the nichrome spiral inside the ceramic tube.
You will also need screwdrivers (Phillips and flat), possibly star keys (Torx), as many manufacturers, such as LG or Samsung, use them to fasten panels. A light source (flashlight) will not be superfluous, since the niche of the evaporator is often dark, and it is important to clearly see the condition of the contacts and wires.
Compliance with safety precautions is not just a formality, but a mandatory condition. Working with live electrical appliances is strictly prohibited. Before starting any work, make sure that the refrigerator is unplugged. Even if you only plan to remove the back cover, the risk of accidentally touching live parts or a short circuit due to careless handling of the wires is too great.
☑️ Preparing for diagnostics
Access to the heating element and visual inspection
The location of the heating element depends on the design of the refrigerator. In most models with the No Frost system, the heating element is hidden behind the back panel of the freezer. To access it, you need to completely defrost the unit (if it is not already covered with ice), remove all shelves and drawers, and then dismantle the plastic casing.
The process of removing panels requires care. Plastic becomes brittle at low temperatures, and sudden movement can cause the latches to break. Fastening elements can be hidden under decorative plugs or stickers. Carefully inspect the perimeter of the panel, feel for the presence of screws. After removing the fasteners, the panel usually moves up or snaps off around the perimeter.
When access to the evaporator is open, you will see an aluminum radiator (evaporator) and a heating element located next to or built into it. A visually serviceable element should not have swelling, cracks or signs of corrosion. The wires approaching the contacts must be intact, without melted insulation. Sometimes a break occurs not in the tube itself, but at the place where the terminals are soldered or crimped.
Design features of heating elements of different brands
Indesit and Ariston refrigerators often use heating elements in the form of a curved tube that goes around the evaporator. In Bosch and Siemens models, the heater can be enclosed in a separate aluminum profile. Some modern LG models use a linear defrost system, where the heating element is a flexible tape glued to the surface of the evaporator. The design affects the method of dismantling, but the principle of testing remains the same for all types.
Method of testing with a multimeter
The most reliable way to find out the condition of a part is to measure its electrical resistance. To do this, put the multimeter in resistance measurement mode (indicated by the Ω symbol), selecting the limit of 2000 Ohms (2 kOhms) or 20 kOhms. If your device has a “dialer” mode (with a sound signal), it is also suitable for the initial check for a break.
Disconnect the wires from the contacts of the heating element. This is a must, otherwise you can measure the resistance of the entire refrigerator circuit, not just the heater. Touch the tester probes to the two ends of the heating element. The display should show specific numbers. For household refrigerators, the defrosting power is usually in the range of 300-500 W, the normal resistance is from 200 to 400 Ohms.
If a unit (infinity) or the “OL” (Over Limit) symbol is displayed on the device screen, this means open circuit. The nichrome thread inside has burned out, and current does not flow through it. This heating element must be replaced. If the device shows zero or a value close to zero, this indicates a short circuit inside the element, which is also a malfunction.
An important step is checking for breakdown on the housing. Set the multimeter to resistance measurement mode at the maximum limit (2 MΩ or higher). Press one probe to the contact of the heating element, and the second to the metal tube or heater body. The device should show infinity. If the arrow deviates or the numbers light up, it means that the insulation is broken and the element “breaks through” onto the housing. Using such a heater is dangerous to life.
Resistance standards and table of values
Understanding physical processes helps to better interpret instrument readings. The resistance of the heating element depends on its power and the material of the spiral. When heated, the resistance of the metal increases, but at room temperature (cold heating element) it has a stable value, which we measure.
Below is a table of approximate resistance values for heating elements of various powers, designed for a network voltage of 220-230 Volts. This data will help you determine whether your part meets the declared characteristics.
| Heating element power (W) | Approximate resistance (Ohm) | Current strength (A) | Probable malfunction |
|---|---|---|---|
| 200 W | ~250 - 280 Ohm | ~0.9 A | Open (∞) or short circuit (0) |
| 300 W | ~170 - 190 Ohm | ~1.4 A | Breakdown to the body |
| 400 W | ~120 - 140 Ohm | ~1.8 A | Resistance change >10% |
| 500 W | ~90 - 110 Ohm | ~2.3 A | Unstable contact |
It is worth noting that a small deviation within 5-10 Ohms from the calculated value is acceptable and due to the error of the measuring instrument or the ambient temperature. However, if the resistance is significantly higher than normal, this may indicate partial burnout of the spiral or oxidation of the contacts inside the sleeve.
Diagnostics of related system elements
It often happens that the heating element itself is working, has the correct resistance, but does not turn on. In this case, the problem lies not in the heater, but in the controls. The defrost system is a chain consisting of several links: a heating element, a defrost sensor (thermostat), a thermal fuse and a timer (or electronic module).
Particular attention should be paid thermal fuse. This is a one-time protection element that burns out if the temperature in the evaporator zone becomes critically high (for example, when the relay contacts stick). Checking the fuse is similar to checking the heating element: if it is in good condition, it should “ring” (show zero or very low resistance), if it is burnt, it should show a break.
Also check the defrost sensor. He is responsible for turning off the heating element when the ice melts. At room temperature, this sensor should be open (not conduct current), and when cooled (for example, if you put it in the freezer for 15-20 minutes), it should close the circuit. A malfunction of this sensor can lead to the heating element either not turning on at all or heating constantly, which is dangerous.
⚠️ Attention: When replacing the heating element, it is strongly recommended to change the thermal fuse, even if it “rings”. Its resource could be exhausted, and repeated activation of the protection will leave you without defrosting at the most inopportune moment.
Frequent errors during diagnostics and replacement
One of the common mistakes is ignoring the condition of the wires. During the defrosting process or due to vibration, the wires may rub against the edges of the metal case or sharp plastic edges. Visually, the insulation may appear intact, but when moving, the conductor inside may lose contact. Always check the integrity of the line from the connector to the heating element itself.
Another mistake is installing a heating element of inappropriate power. Some users, not finding an original spare part, install a higher power element “just to heat it up”. This leads to overloading of the wiring, melting of the plastic elements of the evaporator housing and rapid failure of the thermal fuse. Use only those parts whose parameters match the original.
Do not forget about the build quality after repair. A poorly screwed heating element may not fit tightly to the evaporator, which will reduce the efficiency of heat transfer. The element itself will heat up, not the ice. Conversely, tightening the fasteners too tightly can damage the aluminum tubes of the evaporator, which will lead to freon leakage and expensive repairs.
Is it possible to temporarily operate a refrigerator without a heating element?
Technically, the refrigerator will work and cool food, but only in manual control mode. You will have to regularly (once every 1-2 weeks) completely disconnect the unit from the network and defrost it manually for 10-12 hours. If this is not done, the ice will completely block the air circulation channels, and the refrigerator will stop freezing, and the compressor will burn out from overload.
Why does the heating element burn out in the refrigerator?
The main reason is corrosion. During operation, condensate forms on the aluminum body of the heating element and evaporator, which contains impurities of salts and acids from the air and products. Over time, the metal becomes thinner, microcracks form, moisture penetrates inside and causes a short circuit or oxidation of the contacts. Also, the cause may be a malfunction of the sensor, leaving the heating element on for too long.
How to distinguish an original heating element from an analogue?
Original spare parts are often marked by the manufacturer of the refrigerator (for example, Samsung, LG, Whirlpool logos) and are packaged in branded boxes with barcodes. Analogs can be packaged in simple packages, have Generic markings, or differ in the geometry of the fasteners. It is also important to pay attention to the quality of the insulation of the wires and solder - in cheap copies they are often made of materials that quickly lose their properties when heated.