The sudden appearance of ice on the back wall of the refrigerator compartment or the lack of defrost in the freezer compartment often indicates a failure of the No Frost system. In most cases, the culprit is heating element, which stops warming up the evaporator during the defrost cycle. If you ignore this problem, the ice coat will grow, blocking air circulation and causing the compressor to wear out, which will inevitably lead to serious damage.
Checking the heating element (tubular electric heater) is a basic procedure that can be performed independently with a minimum set of tools. You do not need to be a professional electrician to carry out an initial diagnosis, but compliance with safety precautions is a must. Before starting any work make sure that the refrigerator is unplugged from the mains, as working with live electrical components is deadly.
In this article we will look in detail at how to determine malfunction, what tools are needed for accurate measurements and what to look for during a visual inspection. Understanding the principle of operation defrost systems will help you save time on calling a technician or quickly fix the breakdown on your own, returning the unit to operability.
Principle of operation and signs of a heating element malfunction
Heating element in refrigerators with system No Frost or Full No Frost performs a critical function: it heats the evaporator during the defrost cycle, turning frozen frost into water, which then flows into the drain pan. This process is started by the defrost timer or control electronics. If the heating element burns out, the ice stops melting, accumulates and eventually completely blocks the ventilation ducts.
The first and most obvious sign of a malfunction is deterioration in cooling or its complete absence, despite the fact that the compressor continues to hum. You may notice that the back wall of the refrigerator compartment is covered with a thick layer of ice or “coat”, and the food in the freezer begins to thaw. Also, breakdown is often indicated continuous operation of the compressor without stop cycles, since the temperature sensor cannot break through the layer of ice to the air in the chamber.
⚠️ Attention: If you notice that the refrigerator is constantly running and does not turn off, do not try to forcefully defrost it with a hairdryer or hot water. A sharp temperature change can damage the plastic housing of the evaporator or lead to cracks in the freon tubes.
In addition, an indirect sign may be the absence of the characteristic sound of water murmur or a click of mode switching, if these sounds were heard previously in your model. In some modern models with electronic control, the display may light up error code, indicating problems in the defrost circuit, but accurate diagnostics are still best carried out using hardware methods.
Required tools and safety measures
For high-quality diagnostics you will need a standard set home handyman. The main tool will be multimeter (tester), which allows you to measure the resistance of the circuit and check for a breakdown in the case. Without this device, the check will be only visual, which does not always give a reliable result, since a break in the spiral inside the tube may not be visible to the eye.
You will also need screwdrivers (Phillips and flat) to remove panels, protective gloves for working with sharp edges and, possibly, a hair dryer to speed up defrosting if ice interferes with access to the heating element. Don't forget to prepare a container to collect water that forms when ice melts during dismantling.
- 🔧 Multimeter with continuity function and resistance measurement (Ohm).
- 🪛 Set of screwdrivers of different sizes and slot types.
- 🧤 Protective gloves and rags for cleaning moisture.
- 🔦 Flashlight for illuminating hard-to-reach places behind the back wall.
Safety is priority number one. Before removing the back panel in the freezer, be sure disconnect the refrigerator. Even after unplugging, capacitors may retain residual charge, so do not touch live parts with bare hands immediately. It is also worth waiting for the water to completely drain if you carried out defrosting, in order to avoid a short circuit when turning on the equipment for testing.
Step-by-step instructions for dismantling the heater
Access to the heating element in most refrigerator models (Indesit, Samsung, LG, Bosch) is located in the freezer. You will need to remove the back plastic panel that hides the evaporator. In some cases, it is also necessary to remove the air dampers or sensors attached to this panel.
The process begins with completely emptying the freezer compartment of food and drawers. If there is a lot of ice on the walls, leave the refrigerator turned off for several hours or carefully remove the ice to gain access to the panel mounting screws. Often the screws are hidden under plastic plugs or stickers that need to be carefully removed.
☑️ Algorithm for dismantling the heating element
After removing the panel, you will see the aluminum evaporator radiator to which the heating element is attached. It may look like a curved tube encircling the evaporator from below, or as a separate element in the form of a “hoof”. Carefully disconnect the wire connectors going to the heater. Sometimes they can be melted or oxidized, which requires cleaning the contacts before installing a new element.
The heating element itself is usually mounted on special brackets or clips. Be careful when removing it: if it is stuck to ice or corrosion, do not use excessive force to avoid breaking the fragile aluminum evaporator. It is better to slightly warm up the mounting location with a hairdryer or let the ice melt completely.
Diagnostics with a multimeter: measuring resistance
The most reliable way to check the heating element is to measure its electrical resistance. To do this, set the multimeter to resistance measurement mode (usually denoted as Ω or Ohm) to the 2 kOhm limit. If your tester has a continuity mode, it is also suitable for the initial check of circuit integrity.
Attach the multimeter probes to the contacts of the heating element. A working heating element should show a certain resistance, which depends on its power. For most household refrigerators, a value in the range from 200 to 500 Ohmis considered normal. Accurate data can always be found in the technical documentation or on the marking of the element itself.
| Multimeter reading | Diagnosis | Actions |
|---|---|---|
| ∞ (Infinity) or 1 | Open circuit (burnt out) | Replacement of heating element |
| 0 Ohm or close to 0 | Short circuit | Replacement Heating element |
| 200–600 Ohm | Normal (good) | Checking other nodes |
| Floating values | Unstable contact | Cleaning the terminals |
If the device shows a unit or an infinity symbol, this means that the nichrome spiral inside the tube has burned out and no current is passing. In this case, the heating element can only be replaced, it cannot be repaired. If the resistance is close to zero, it means that a short circuit of the turns has occurred, which also requires replacement of the part.
Why can the resistance be different?
The resistance of the heating element depends on its power and the length of the nichrome spiral. The more powerful the heater, the lower its resistance. For example, a 300 W heating element will have less resistance than a 150 W heating element. Always check the markings.
Checking for insulation breakdown (frame short)
Even if the coil resistance is normal, the heating element may be faulty due to insulation failure. In this case, the current can “break through” to the metal body of the refrigerator, which creates a risk of electric shock for the user and can knock out the circuit breakers in the panel.
To check, switch the multimeter to the resistance measurement mode at the maximum limit (usually 2 MOhm or 20 MOhm). Apply one probe to the contact of the heating element, and the second to its metal body (tube). On a working device, the arrow should not deviate, and one (infinity) should be lit on the digital screen.
If you see any resistance values between the spiral and the housing, it means the insulation is broken. Operate such a refrigerator strictly prohibitedas the entire body may be energized. Moisture, condensation and the metal structure of the refrigerator create ideal conditions for electric shock.
- ⚡ Set the maximum measurement limit on the multimeter.
- 🔌 One probe for the contact, the second for the metal tube of the heating element.
- ✅ Normal: the device shows infinity (1).
- ❌ Breakdown: the device shows any numerical value.
⚠️ Attention: Never use a heating element with broken insulation, even temporarily. This is a direct threat to life. In addition, leakage current can damage the electronic control board of the refrigerator.
Typical errors and visual inspection
When diagnosing, they often make a mistake by relying only on appearance. The heating element may look intact, without visible breaks or swelling, but the coil inside may be burnt out. Conversely, a slight coating or discoloration of the tube does not always indicate a breakdown - this may be a consequence of normal operation.
However, there are signs that clearly indicate a problem. Pay attention to the condition of the contacts: if they are blackened, melted or oxidized, this indicates poor contact, which could lead to overheating and failure of not only the heating element, but also the wiring. In such cases, you need to clean the contacts or replace the terminal block.
It is also worth checking the condition of the evaporator itself around the heating element. If you see signs of corrosion, pig snouts, or damage to aluminum tubing, this may be the result of galvanic corrosion caused by current leakage. In such a situation, simply replacing the heating element may not be enough - more complex repairs will be required.
What to do if the heating element is working, but there is no defrosting?
If a check shows that the heating element is fully operational, but the refrigerator still does not defrost, the problem lies in other elements of the system. The defrost circuit also includes defrost temperature sensor, relay (timer) and, in some models, fuse. Failure of any of these components interrupts the supply of voltage to the heater.
Most often, the defrost sensor fails, which should close the circuit at a certain temperature evaporator. If it is “stuck” in the open state, the command to turn on the heating element will never be received. It is also worth checking the defrost fuse, which burns when the system overheats, opening the circuit forever.
To diagnose these elements, you will also need a multimeter. The sensor is checked for resistance at different temperatures, and the fuse is checked for integrity (resistance should be close to zero). If you are not confident in your abilities, it is better to contact a specialist, since replacing these parts requires precise adjustment of the parameters.
In conclusion, it is worth noting that regular maintenance and timely defrosting (even for the No Frost system, if it is provided for in the instructions) prolong the life of the heating elements. Keep the drainage system clean, as blockages can lead to water accumulation and corrosion of the contacts.
Is it possible to check the heating element without a multimeter?
It is impossible to carry out an accurate check without a multimeter. You can only visually inspect the element for obvious breaks or connect it directly to a 220V network (using extreme caution!), but this method is dangerous and is not recommended for beginners. If the heating element heats up when connected to the network, it is working, but the risk of electric shock is too great.
Which heating element to choose for replacement: original or analogue?
Ideally, it is better to look for an original spare part by catalog number. However, high-quality analogues (for example, from well-known component manufacturers) are often not inferior to the original. The main thing is to observe the geometric dimensions (so that it fits into place) and the power (Watts), which must match the original.
Why did the new heating element burn out after a week?
Most often, the reason lies in a faulty defrost sensor or timer, which does not turn off the heating on time, causing overheating. It is also possible that there is a poor connection at the terminal block, causing arcing and voltage surges. Before installing a new heating element, be sure to check the entire circuit.