Modern refrigerators with a system No Frost or drip defrosting are equipped with a complex defrosting system, the key element of which is a tubular electric heater. When the unit stops freezing, and a “coat” of ice grows on the back wall inside the chamber, the first thought of the technician is to check this particular component. Understanding how to ring the heating element allows you to quickly determine the cause of the malfunction and avoid a costly call to the service department to simply replace the part.
The heating element operates in an aggressive environment, where extremely low temperatures alternate and heating up to hundreds of degrees, which over time leads to burnout of the nichrome spiral or destruction of the insulation. Unlike mechanical breakdowns, electrical breakdown or open circuit is often not visible to the naked eye, requiring the mandatory use of measuring instruments. Multimeter in this case, it becomes the main tool that allows you to say with absolute accuracy whether the heater is alive or it’s time to change it.
Before you begin before disassembly, it is important to realize that diagnosing the heating element is only part of checking the defrost system, which also includes a thermostat and timer. However, it is the heater that most often fails due to natural wear and tear or power surges in the network. Disconnection takes only a few minutes, but requires compliance with strict safety rules and sequence of actions so as not to damage other components of the refrigerator.
⚠️ Attention: All work on diagnosing and replacing the electrical components of the refrigerator should be carried out exclusively when the refrigerator is turned off from the power supply network. Residual voltage in capacitors or accidental plugging into a socket during disassembly can lead to electric shock.
Principle of operation and types of heating elements
The heating element in the refrigerator is a metal tube, inside of which a nichrome spiral is insulated from the walls compressed powder, usually magnesium oxide. Depending on the design of the refrigerator, heaters can be located in different places: under the evaporator, around it, in a drainage tray, or in the form of a glass tube inside the chamber. Each type performs its own function, but the principle of checking them remains similar.
The most common are open heating elements, which are mounted directly on the aluminum evaporator. They heat up quickly and effectively thaw ice, but are susceptible to corrosion. Glass heaters, often found in older models or in drip zones, are more durable, but fragile under mechanical stress. Resistance functional element is the main parameter that we will measure.
It is important to understand what is in the system No Frost several independent heating elements can be used: one for the main evaporator, another for the blowing zone and a third for drainage. Failure of even one of them disrupts the balance of the system, leading to ice freezing in the air ducts. Therefore, diagnostics must be comprehensive, covering all available heating circuits.
Why does the heating element burn out?
The main cause of failure is local overheating. If the ice does not have time to completely melt during the defrost cycle, the next heating occurs along the formed ice crust, which leads to thermal shock and rupture of the coil. There are also frequent cases of oxidation of contacts at the junction with the wiring.
Necessary tools and preparation for diagnostics
For a high-quality check, you do not need a complex professional kit, but basic tools are required. The main device will be multimeter (tester), capable of measuring resistance (Ohms) and checking the integrity of the circuit ("continuity" mode). Without this device, it is almost impossible to visually determine the internal break of nichrome.
In addition to the measuring device, you will need screwdrivers (Phillips and flat) to remove the panels, as well as pliers or wire cutters to bite off the insulation if the wires are connected by twisting. In some models Indesit or Atlant access to the heating element may be difficult, and you will need to partially dismantle the internal shelves or drawers of the freezer.
Be sure to prepare a dry rag and a container for water, as condensation may leak when defrosting and removing the panels. Before starting work, the refrigerator must be completely defrosted and left at room temperature for at least 2-3 hours so that residual moisture does not cause a short circuit when turned on again.
☑️ Preparation for checking the heating element
Dismantling and visual inspection Heating element
Access to the heater is usually located in the freezer. It is necessary to remove the back panel covering the evaporator. In refrigerators LG or Samsung it is often attached to latches and screws hidden under decorative plugs. Proceed carefully, as plastic becomes brittle in the cold and can crack.
After removing the panel, access to the evaporator and the heating element located underneath will open. Visually assess the condition of the element: there should be no swelling, tube ruptures or obvious signs of corrosion penetrating the metal. If the tube is deformed or has through-hole damage, further testing may not be necessary - the element requires replacement.
Pay special attention to the places where the wires are connected. It is often the terminal connections that oxidize or burn. If you see carbon deposits or melted insulation on the contacts, this is a sign of poor contact, which could lead to overheating and failure of the heating element. In such cases, not only the heater is changed, but also the terminal block.
⚠️ Attention: The design of refrigerators from different manufacturers may differ. In models with the “Total No Frost” system, access to the heating element may require dismantling the entire air duct. Do not use excessive force when removing plastic parts.
Multimeter testing technology
The most critical stage is direct measurement. Switch the multimeter to resistance measurement mode (denoted as Ω), selecting a limit of 2000 ohms (2kohms). If your device has a “continuity” mode (speaker icon), you can use it, but the Ohms mode will give a more accurate picture of the state of the coil.
Touch the tester probes to the two terminals of the heating element. It doesn't matter which probe you connect to which pin, since the resistance does not depend on polarity. If the display shows one on the left or the value “OL” (Over Limit), this means an open circuit. The nichrome spiral inside has burned out, and current does not flow through it - such a heating element is faulty. open circuit. The nichrome spiral inside has burned out, and current does not flow through it - such a heating element is faulty.
If the device shows a specific numerical value, usually in the range from 200 to 400 Ohms for household refrigerators with a power of 300–500 W, then the circuit is intact. For reference: the higher the power of the heating element, the lower its resistance. For example, a heating element with a power of 400 W at a voltage of 220 V should have a resistance of about 120 Ohms. A significant deviation from the norm (for example, 5–10 Ohms or several kOhms) indicates a malfunction.
Checking for insulation breakdown (short circuit to the body)
Even if the spiral is intact, the heating element can be dangerous. It often happens that nichrome is destroyed inside the tube and touches the metal walls, or the insulating powder is damaged. In this case, a potential appears on the heater body, which can lead to an electric shock when touching the metal parts of the refrigerator or tripping the RCD.
To check for breakdown, press one multimeter probe to any terminal of the heating element, and the second to the metal tube of the heater itself (pre-clean a small area of oxides for better contact). In good condition, the device should show infinity (1 or OL).
If the tester shows any resistance value or emits a beep, then it exists breakdown to the body. It is strictly prohibited to operate such a refrigerator, as this poses a direct threat to people’s lives. Such a heating element must be immediately disposed of and replaced; it cannot be repaired.
The procedure for checking for breakdown:1. Probe 1 -> Heating element output
2. Probe 2 -> Metal tube of the heating element
3. Result "1" or "OL" -> Normal
4. Result "0" or numbers -> Breakdown (dangerous!)
Typical resistance values and correspondence table
To make it easier for you to navigate the device readings, we have prepared a table with approximate resistance values for heating elements of various powers. Remember that measurements are taken on a cold element, since the resistance of nichrome increases when heated.
Keep in mind that in some complex defrosting systems (for example, in refrigerators Bosch or Siemens) heating elements can be connected in series or parallel. In such cases, the overall circuit needs to be “gutted” by disconnecting the wires to check each element separately.
| Power of the heating element (W) | Rated voltage (V) | Expected resistance (Ohm) | Status |
|---|---|---|---|
| 300 | 220 | ~160 | Normal |
| 400 | 220 | ~120 | Normal |
| 500 | 220 | ~95 | Normal |
| Any | 220 | ∞ (Infinity) | Break |
| Any | 220 | 0 | Short circuit |
Frequent errors and additional recommendations
One of the most common mistakes is trying to check the heating element without disconnecting the wires from it. In this case, you can “ring” not the heater itself, but a parallel circuit through a thermostat or timer, receiving false readings. Always disconnect at least one wire from the element being tested.
Also, do not ignore the state of the thermal fuse, which is often installed in close proximity to the heating element or on its body. If the fuse is blown, the circuit will be broken and the multimeter will show a break, although the heating element itself may be intact. Check the fuse separately in the continuity mode.
If, after replacing the heating element, the problem with ice freezing does not disappear, the defrost sensor or timer may be faulty. The system works in tandem, and the failure of one component can mask the problem of another. Comprehensive diagnostics saves time and money in the long run.
⚠️ Attention: Technical characteristics and location of components may vary depending on the year of manufacture and the specific modification of the refrigerator. Before ordering spare parts, check the part numbers with the official documentation of the manufacturer or the markings on the nameplate of your device.
Questions and answers (FAQ)
Is it possible to temporarily use a refrigerator if the heating element is burnt out, but the freezer is working?
Technically, the refrigerator will freeze, but only until the evaporator is completely covered with ice and blocks the air circulation channels. After this, the temperature in the chambers will begin to rise, and the compressor will work without stopping. Operation in this mode leads to rapid failure of the compressor, so repair is required.
Why does a new heating element burn out a week after replacement?
Most often, the reason lies not in the heater itself, but in a malfunction of the defrost temperature sensor or timer. If the sensor is “stuck” in the “heating” position, the heating element works constantly, and not in cycles, which leads to its overheating and burnout. Be sure to check the entire defrost control circuit.
Is it possible to restore a burnt-out heating element by welding or soldering?
No, nichrome spirals cannot be restored qualitatively in domestic conditions. Any welding will disrupt the metal structure and the tightness of the tube, which will lead to rapid repeated failure or breakdown of the housing. The cost of a new heating element is low, so replacement is the only safe solution.
How often do you need to change the heating element in a No Frost refrigerator?
The heating element is not a consumable item with a regulated replacement period. If the rest of the automation is working properly, it will last for years, often the entire lifespan of the refrigerator. Frequent replacements (every 1–2 years) indicate a systemic problem in the electronic module or sensors.