Heater in the refrigerator: device and purpose

A modern refrigerator is a complex unit, in in which cold is created artificially, but paradoxically, heating elements are necessarily present inside it. Many owners of household appliances are perplexed when they discover warm areas on the body or learn about the presence of Heating elements (tubular electric heaters) in a design designed for cooling. A logical question arises: why are heating devices installed in the freezer, where a negative temperature must be maintained?

The answer lies in the physics of the refrigerant and the need to combat moisture. Without periodic heating of the evaporator, the system would quickly become covered with an ice crust, blocking air circulation, and condensation would constantly appear on the outer walls, leading to corrosion. Understanding the operating principle of these elements helps owners better operate equipment and notice malfunctions in time.

In this article we will take a detailed look at what types of heaters are used in refrigeration equipment, how they affect energy consumption and what to do if the defrost system fails. You will learn why No Frost cannot work without heat and how to diagnose a breakdown of the heating element before the food spoils.

Main functions of heating elements

The main task of any heater in the refrigeration circuit is to control the temperature in strictly defined zones to ensure the stability of the compressor and maintain the properties products. Evaporator defrost is the primary function. During the cooling process, moisture from the food air settles on the cold evaporator tubes, turning into frost. If this ice is not removed, it builds up, insulating the heat exchanger and blocking air flow.

The second important function is fighting condensation on external surfaces. In areas of contact between warm room air and cold internal circuits (usually doorways), the surface temperature can drop below the dew point. To prevent water from flowing on the body, a heating circuit is laid along the perimeter of the door.

Heaters are also used to prevent freezing of the drainage holes. The water generated during defrosting must flow freely into the pan. If the tray or tube freezes, water will flow into the chamber or onto the floor. It is critical to understand that the heater operates cyclically and only at the command of the thermostat or timer, and not constantly.

⚠️ Attention: If you feel that the back wall inside the refrigerator compartment has become hot and the food is freezing, this is a sign of sticking heater relay contacts. Immediately disconnect the device from the network.

Types of heaters in modern technology

Structurally, heating elements are divided into several types depending on their location and purpose. The most common is defrost heating element. It is a metal tube, inside of which a nichrome spiral is enclosed in a dielectric filler. In systems No Frost such an element is located directly under the evaporator in the freezer.

Another type is anti-condensation heaters. Previously, these were separate tubular elements laid along the contour of the door. In modern models, especially in the budget segment, their function is often performed by hot refrigerant pipes (circuit) leaving the compressor. However, premium models still use electric heaters, which turn on only when the humidity in the room is high.

The third type is heaters drainage tray. These are small-power elements that prevent the formation of an ice plug at the point where water exits the defrost system. They turn on synchronously with the main heating element for defrosting the evaporator.

Principle of operation of the defrosting system

The ice removal process is automated and does not require human intervention. The refrigerator controller monitors the operating time of the compressor or the temperature of the evaporator. When the time for defrosting comes, the compressor and fan stop, and voltage is applied to the defrost heating element. Heated air begins to circulate inside the freezer (in a closed circuit behind the back wall), melting the ice. The resulting water flows down the gutter into the drainage hole. It is important that the heating process is controlled defrost heating element.

Heated air begins to circulate inside the freezer (in a closed circuit behind the back wall), melting the ice. The resulting water flows down the gutter into the drainage hole. It is important that the heating process is controlled thermal fuse i defrost thermostat. As soon as the ice melts and the temperature of the sensor rises to a certain value (usually +10...+15°C), the circuit breaks and heating stops.

After completion of the defrost cycle, the compressor does not start immediately. Time is given for the temperatures to equalize and the remaining water to drain. Only after this the refrigerator starts to freeze again. This algorithm protects the system from water hammer and ensures effective heat transfer.

Diagnostics of heater faults

You can understand that the heating element has failed by indirect signs, without resorting to complex equipment. The most obvious symptom is a “fur coat” or an ice shell on the back wall of the freezer in models No Frost. If the fan is humming, but the cold does not pass into the refrigerator compartment, and ice is visible on the evaporator, most likely the heating element is not heating.

The second sign is water on the floor under the refrigerator or inside the bottom shelf. This indicates that the drain hole is frozen and there is nowhere for the water to drain. This often occurs due to a malfunction of the drain heater or the main defrost heating element.

The third symptom is continuous operation of the compressor. Trying to compensate for the lack of air circulation due to the ice jam, the motor wears out, trying to gain temperature. At the same time, the inside may be warmer than set.

Checking and replacing the heating element

To diagnose the heating element, a multimeter is required. Before starting any work, the refrigerator must be completely disconnected from the power supply. You need to get to the evaporator by removing the back panel in the freezer. Visually inspect the heating element: there should be no swelling, ruptures or signs of corrosion.

The check is carried out in the resistance measurement mode (Ohms). The multimeter probes are applied to the contacts of the heating element. A working element will show a resistance in the range from 200 to 500 Ohms (the value depends on the power and model). If the device shows one (infinity) or zero, the element is faulty and requires replacement.

Replacement is made by dismantling the old element and installing a new one of similar power and geometric shape. It is also important to check defrost thermostat i thermal fuseas they often fail in conjunction with the heater or cause it to burn out.

⚠️ Attention: Technical characteristics of heaters (power, dimensions, type of fastening) are unique for each series of refrigerators. The use of non-original analogues can lead to a fire or insufficient defrosting efficiency.

Impact on energy consumption

Many users fear that the presence of heaters significantly increases electricity bills. In practice, the energy consumption of heating elements is a small proportion of the total energy balance of the refrigerator. The main consumer remains the compressor.

The defrost heater turns on briefly. Even a powerful 400 W heating element, operating for a total of 1 hour per day (several cycles), will consume only 0.4 kWh. For comparison, a compressor can consume 1-1.5 kWh per day. Thus, the contribution of the defrost system to the total bill is about 15-20%.

However, if the heater “sticks” when turned on due to a faulty relay, energy consumption can increase significantly, and the food in the refrigerator compartment will spoil due to the heat. Therefore, the serviceability of the automatic switching system is more important than the power of the element itself.

Frequently asked questions (FAQ)