If the dishwasher Bosch stopped warming the water, the wash cycle is interrupted at the rinse stage, and the dishes remain drops of detergent, so the heating system has failed. The lack of water temperature rise is often accompanied by an error code. E09 or E22 on the display, which signals a malfunction of the TEN or temperature sensor. In some models with a function AutoDry (zeolite heating) The lack of heat also indicates problems with the energy recovery system.
Violation of the temperature regime leads to the fact that the fat is not dissolved, and the bacteria are not destroyed, which makes the operation of the technique meaningless. Modern models Bosch Serie 4 and Serie 6 They are equipped with sophisticated electronics that block the pump from starting in the absence of heating to prevent the discharge of untreated water. Understanding the heating element and diagnostic algorithms will help determine whether a part needs to be replaced or if it is enough to reset the error.
It is important to note right away that ignoring the problem can lead to the failure of the control module, as it constantly tries to compensate for the lack of heat, working at the limit of current loads. A critical sign is a sharp shutdown of the machine in the middle of the cycle with a flashing indicator of salt or rinse. Further diagnosis requires verification of the integrity of the power chain and the state of the sensory elements.
The main reasons for the lack of water heating
The most common reason why a dishwasher Bosch does not heat water, is the failure of the tubular electric heater (TEN). Over time, scale is formed on the surface of the spiral, which worsens heat transfer and leads to burnout of the nichrome thread. In models with a flow heater, the risk of breakdown is higher due to constant contact with water under pressure.
The second most common factor is a malfunction of the thermostat or temperature sensor (NTC). If the electronics get the wrong temperature data, it simply does not apply voltage to the heating element. In some cases, the contacts on the terminals of the sensor are oxidized, which breaks the control chain.
- 🔥 Breakdown or break of the TEN spiral due to aging metal or voltage surges in the network.
- 🌡️ Failure of the thermostat, which does not close the chain at low water temperature.
- 💻 Failure of the electronic control module, which does not give a signal to turn on the heating.
- 🚫 Blocking the heating function due to leak sensor error (system) AquaStop).
It is also worth considering the state of wiring inside the body. Vibrations during machine operation can lead to weakening of contacts or rubbing of insulation of wires going to the heater. Visual inspection of the wire harness often allows you to identify melted areas or oxidized connectors.
⚠️ Warning: Before any diagnosis, be sure to turn off the dishwasher Bosch from the power grid. Working with electrical appliances under tension is deadly.
Error Diagnostics and Fault Codes
Modern dishwashers Bosch equipped with self-diagnostics, which displays information about the malfunction on the display or indicates it by flashing indicators. Error code E09 This is a direct indication of the problem with water heating. However, the indication may differ from one series of techniques, so it is important to properly decipher the signal.
To accurately determine the problem, you can use the service mode or analyze a combination of flashing indicators. For example, the simultaneous blinking of the indicators "Salt" and "Rinseer" often indicates that the water did not heat up to the desired temperature in the allotted time.
If the display does not show the code, but the machine behaves strangely (long standing, humming, but does not wash with hot water), the problem may lie in a software failure. In this case, a complete system reboot helps by turning off power for 15-20 minutes. If the error is repeated after the inclusion, a hardware check of the components is required.
| Code/Signal | Meaning | Probable cause |
|---|---|---|
E09 |
Heating error | Faulty TEN or thermostat |
E22 |
Problem with filter/heating | Clog or temperature sensor |
| Salt indicator | Low temperature | The water didn't heat up to 50°C. |
| Wash indicator | Cycle failure | Interruption due to lack of heat |
Remembering error codes makes it much easier to find a spare part. If the car shows E09In 80% of cases, a replacement will be required. In other cases, the wiring and control module are checked.
Checking and replacing the TENS with their own hands
If the diagnosis indicated a heating element, it is necessary to conduct a visual and instrumental examination. TEN in dishwashers Bosch It is located at the bottom of the body, under the tank. To access it, you will need to remove the bottom panel or put the car on its side (pre-dumping water).
The first step is to check the integrity of the spiral with a multimeter. The device is switched to the resistance measurement mode (Oma). The normal resistance of a serviceable thermal power plant with a capacity of 2 kW is about 25-30 Ohms. If the device shows one or infinity, the spiral is broken.
☑️ Checklist for TEN checklist
It is also important to check for no breakage on the body. One multimeter probe is applied to the contact of the TEN, the other to the metal housing of the heater. There should be no audible signal in the vertebrae mode. The presence of a breakdown means that the operation of the machine is dangerous and requires immediate replacement of the part.
Replacement of the element is made by unscrewing the fastening bolts and disconnecting the terminals. It is recommended to photograph the connection scheme in advance so as not to confuse the wires during assembly. The new TENG should have identical landing dimensions and power.
Failures of the thermostat and sensors
Thermostat in the dishwasher Bosch is responsible for maintaining the specified temperature and turning off the TEN when the desired value is reached. If this component is "stuck" in the open state, heating will not begin at all. The design of the thermostat can be mechanical (bimetallic plate) or electronic.
A temperature sensor (NTC) is a thermistor whose resistance varies with the heating of water. If it malfunctions, it can transmit a false signal to the control module that the water is already hot, and the heating will not turn on. The test is carried out by measuring resistance at different temperatures.
- 🛠️ Mechanical thermostat: is checked for the sticking of the contacts and the integrity of the bimetallic plate.
- 📉 NTC sensor: The resistance that should fall when heated (or increase, depending on the type) is measured.
- 🔌 Contact: They are inspected for oxidation and burning.
Often the problem lies not in the sensor itself, but in the oxidation of contacts in the connector. Moisture and vapor contribute to corrosion, which increases resistance in the chain and distorts readings. Cleaning the contacts and treating them with contact lubrication can solve the problem without replacing the part.
⚠️ Warning: When installing a new thermostat, make sure it fits tightly to the tank or is installed in a special socket. Poor contact will lead to incorrect temperature readings.
Impact of the control module on heating
Electronic control module is the "brain" of a dishwasher Bosch. It is he who decides on the inclusion of TEN based on data from sensors. If all actuators are working, but there is no heating, the problem may be in the power relay on the control board.
The relay responsible for switching the TEN wears out over time. Contacts can burn or stick. Visually, this manifests itself as black soda or melted plastic around the relay. Board repair requires soldering skills and electronics work.
Signs of failure of the control module
If you hear clicks of the relay, but the TENG is not warming, the contacts may have burned. If there is no click at all, the control chip or track on the board has burned. In complex cases, the entire module must be reflashed or replaced.
It is also worth checking the fuse on the board, if it is provided by the design. The voltage surge could have caused it to burn out, which broke the heater's power circuit. Replacing the fuse is a simple procedure, but it does not guarantee that the cause of the jump has been eliminated.
Prevention and care of the heating system
To make the dishwasher Bosch served long and warmed water effectively, it is necessary to regularly carry out preventive measures. The main threat to TEN is scale, which is formed from hardness salts contained in water.
Using a special salt for dishwashers is a must, even if the water in the tap is soft. Salt regenerates the built-in water softener, preventing calcium from settling on the heating element. Regular cleaning of filters also improves water circulation and heat exchange.
Useful tip: Every 2-3 months, run an empty machine with the addition of citric acid or a special means for cleaning scale. This will prolong the life of TEN and improve the quality of the wash.
At least once every six months, it is recommended to check the condition of seals and hoses, as well as clean the sprinklers from food residues. A clean machine works more efficiently, and the load on the heating system decreases.
The main conclusion: 90% of the problems with heating in Bosch machines are solved by replacing the thermal power plant or thermostat. Regular use of salt prevents 80% of heating system breakdowns.
Why does Bosch heat water but fail to show error?
If the water is heated but not enough (e.g., to 30°C instead of 60°C), the machine may not make an error right away. She will try to compensate for the lack of heat by increasing the time of washing. The error will only appear if the temperature does not reach the minimum for the allotted time. This often indicates a partial failure of the TENG (scale overgrowth) or a wedge of the thermostat.
Can I wash dishes if the car does not heat the water?
Technically, you can start the cycle by selecting the "Cold wash" mode or by turning off the heating function (if the model allows). However, the quality of washing will be low: the fat will not dissolve, and the glass may become cloudy. In addition, without hot water, most modern detergents are not activated. Constant operation in cold mode is not recommended.
How to check the TEN without a multimeter?
Without a multimeter, it is difficult to accurately determine the fault of the TEN. Indirect sign – if the machine is gaining water, begins to hum (circulation pump), but after 10-15 minutes the water in the tank remains cold to the touch (through the bottom or hatch), most likely, the TEN does not work. However, an accurate diagnosis tool is needed.