No water heating in the dishwasher Bosch, Electrolux or Candy often indicates a failure of the tubular electric heater, which leads to poor removal of fat and carbon deposits from cutlery. Modern detergents are designed to activate at temperatures between 50 and 70 degrees Celsius, and without proper heating element the chemical reaction simply does not start, leaving the dishes dirty even after a full wash cycle. It is almost impossible to visually determine a breakdown without disassembling the case, so owners notice the problem only by the cold glass of the door at the end of the program or by the appearance of characteristic error codes on the display.
It is critically important not to ignore the first signs of malfunction, since operating equipment with inoperative heating can lead to the accumulation of fatty deposits in the lines and pump. The most common cause of combustion of the coil inside the heating element is hard water and scale., which creates the effect of a thermos, overheating the metal shell to critical temperatures. In some cases, the machine’s electronics may block the program from starting if the temperature sensor detects a lack of heating dynamics within a given time interval.
Before planning to purchase a new spare part, it is necessary to conduct initial diagnostics to rule out controller errors or problems with the power supply. Users often confuse the lack of water heating with a malfunction of the element itself, although the problem may lie in oxidized contacts or a burnt-out relay on the control board. Correct identification of the unit will save time and money by avoiding the purchase of expensive original components if they are not urgently needed.
Malfunction symptoms and error codes
The first and most obvious sign that heating element stopped performing its functions, is the temperature of the dishes and water at the end of the cycle. If you open the car door Indesit or Siemens immediately after the signal for the end of the wash, and it’s cold and damp inside, this is a direct indicator of the problem. In good condition, the dishes should be hot, and steam should actively come out, providing a drying effect, which is also related to the operation of the heating element.
Modern models are equipped with a self-diagnosis system, which displays or indicates specific error codes by flashing lights. These signals help narrow down the troubleshooting to a specific unit, although the interpretation of the codes may vary depending on the brand and series of the device.
- 🔥 E09 (or a combination of blinking indicators) is a frequent code for Bosch and Siemens, indicating a heating error or an open circuit in the heating element.
- ❄️ F5 or F05 - typical for Hotpoint-Ariston and Indesit, indicates a problem with the temperature sensor or lack of heating.
- ⚡ E2 - often found in technology Hansa and Electrolux, indicates a malfunction of the water heating system.
- 🌡️ AL5 - error code associated with overheating or, conversely, underheating of water in machines Candy.
⚠️ Attention: Do not try to reset the error by turning the machine on and off repeatedly. If the heating element is broken into the housing, repeated starts can lead to a short circuit in the apartment’s electrical network.
An indirect but important symptom is the quality of washing greasy dishes. Animal fats melt and emulsify only at temperatures above 45-50 degrees. If you notice that frozen fat remains on the plates, and the glass is covered with a rainbow film, most likely the water in the tank has not reached the desired condition. In this case, even the highest quality powder will not be able to demonstrate its effectiveness.
Design and principle of operation of the heating element
The heating element in dishwashers is a curved metal tube, inside of which a nichrome spiral is insulated from the walls by a compressed dielectric. Unlike washing machines, where the heating element is often located at the bottom of the tank, in dishwashers LG or Samsung it can be built into the bottom of the washing chamber or installed as a flow type along the water circulation path. This design allows you to quickly heat a small volume of water circulating through the sprinklers.
A key element of safety is thermostat or a thermostat that opens the circuit when a critical temperature is reached. This prevents water from boiling and destruction of the plastic parts of the case. In more complex systems, heating control is taken over by an electronic module that receives data from NTC sensor (thermistor), which changes its resistance depending on the temperature of the environment.
Operating principle of a flow heater
In flow-through systems, water heats up instantly, passing through a thin channel with a powerful heating element. This saves energy, but requires perfect sealing, since there should not be any leakage inside the heater.
The service life of the heater directly depends on the quality of the water and the frequency of use of the machine. The scale deposited on the surface of the tube has low thermal conductivity, which forces the spiral inside to work with overload to transfer heat to the water. Sooner or later, local overheating and rupture of the spiral occurs, which leads to complete failure of the unit.
Diagnostics with a multimeter and visual inspection
For accurate diagnostics, it is necessary to provide access to the heating element, which in most models requires partial disassembly of the housing. Before starting work, be sure to disconnect the device from the power supply and turn off the water supply to eliminate the risk of electric shock or flooding.
A visual inspection allows you to identify obvious mechanical damage, such as swelling, cracks in the metal shell or burn marks on the contact group. However, in 80% of cases there are no external signs, and an instrumental check is required using a multimeter in resistance (Ohm) measurement mode and continuity testing.
☑️ Checklist for diagnosing heating element
When testing the outputs of the heating element with multimeter probes, a working element should show a resistance in the range from 20 to 50 Ohms, depending on the power. If the device shows one (infinity), then the spiral has burned out. If zero, a short circuit of the turns has occurred. Pay special attention to checking for breakdown: one probe is placed on the contact, the other on the metal body of the heating element - here the multimeter should be silent.
| Type of check | Multimeter readings (Normal) | Indications in case of malfunction | Diagnosis |
|---|---|---|---|
| Spiral resistance | 20 - 60 Ohm | 1 (infinity) or 0 | Open or short circuit |
| Breakdown to the body | 1 (infinity) | Any values (buzzing/beeping) | Insulation breakdown (dangerous!) |
| Thermal relay (contacts) | 0 (closed when cold) | 1 (open) | Thermal protection malfunction |
| Temperature sensor (NTC) | Depends on T° (usually 10-50 kOhm) | 0 or infinity | Sensor break or short circuit |
If there are no visual defects and the resistance is normal, the problem may be hidden in the control board. In this case, it is necessary to check the presence of voltage at the contacts of the heating element at the moment when the machine is supposed to heat the water. The absence of voltage with a working heating element indicates a malfunction of the relay or triac on the control module.
Step-by-step instructions for replacing the heater
Replacement heating element - a procedure that requires accuracy and the availability of a basic set of tools: screwdrivers, pliers and keys. Depending on the dishwasher model Zanussi or Whirlpool, access to the heating element can be achieved by removing the bottom panel, side wall or completely dismantling the bottom.
The process begins by disconnecting the wires from the contacts of the heating element. It is recommended to take a photograph of the connection diagram before disconnecting, so that during assembly you do not confuse the polarity or connection points of the sensors. After this, the fastening nut or screws holding the heater flange in the seat are unscrewed.
When removing the old heating element, proceed carefully so as not to damage the rubber seal or plastic elements of the tank. The new heater is installed in the reverse order, it is important to fit the rubber seal tightly and tighten the fasteners evenly, avoiding distortions, which can lead to leaks.
⚠️ Attention: It is strictly forbidden to turn on the dishwasher without water (“dry”) after replacing the heating element. This will cause the new part to burn out instantly.
After assembling all components, it is necessary to carry out a test run with a minimum amount of detergent. Carefully monitor the connection points between the heating element and the tank for the appearance of water drops. If everything went well, the machine should take in water, heat it up and begin the wash cycle without generating errors.
The influence of scale and means of prevention
The main enemy of any heating device is scale, consisting of calcium and magnesium salts contained in hard water. Growing on the surface heating element, this layer acts as a heat insulator, reducing heating efficiency and increasing energy consumption. Over time, the layer becomes so thick that heat is no longer transferred into the water, and the coil burns out.
To extend the life of your dishwasher Gorenje or Kuppersberg It is necessary to regularly use special salts to soften water, pouring them into the compartment provided for this purpose. The water hardness concentration can be adjusted in the device menu, which will optimize the operation of the built-in softener.
Use citric acid for prevention once every 3-4 months. Pour 100 grams of acid into the powder compartment and run the washing mode at 60-70 degrees without dishes.
In addition to salts, rinses play an important role, which help wash away residual grease and prevent new dirt particles from sticking to the heating elements and the walls of the tank. Regular use of high-quality chemicals reduces the frequency of necessary maintenance.
Frequently asked questions and answers (FAQ)
Is it possible to wash dishes if the heating element does not work?
Technically, the machine will perform cycles of water intake and drainage, but the quality of washing will be extremely low. Fats will not dissolve, and the glass will remain coated. Additionally, the machine may not proceed to the drying phase or may produce errors.
Why does the car still not heat up after replacing the heating element?
There may be several reasons: the temperature sensor (NTC) is faulty, the thermal relay is burned out, there is a problem with the wiring, or the control module is faulty. It is necessary to carry out comprehensive diagnostics of the entire heating circuit.
How often do you need to change the heating element in a dishwasher?
When using a water softener and high-quality chemistry, the heating element lasts 5-7 years or more. In conditions of very hard water and lack of prevention, the service life can be reduced to 2-3 years.
Is it possible to descale the old heating element and put it back?
Mechanical cleaning is dangerous due to damage to the metal shell. Chemical cleaning with acid is possible, but if the heating element has already burned out (no resistance), cleaning will not help - only replacement.
Which heating element is better: original or analogue?
Original spare parts guarantee full compliance with geometry and power. High-quality analogues (for example, Thermowatt) are often as good as the originals, but cheap copies can quickly fail or have looseness during installation.
Timely replacement of the heating element and use of a water softener will double the life of the dishwasher.