Error A4 Heater Bosch

What is the fault of the A4 Bosch error affecting your heater?

Have you noticed that your Bosch heater is not working correctly and is displaying the A4 error code on the screen? Today, we will explain what this error might signify, its possible causes, and how you can resolve it easily and quickly.

The A4 error code indicates that there is a problem with the combustion sensor of your Bosch heater. The combustion sensor is a device that measures the amount of oxygen and carbon monoxide in the heater's exhaust gases to ensure efficient and safe combustion. If the sensor detects abnormal levels of these gases, the heater locks itself and displays the A4 error code on the screen.

The possible causes that may lead to the appearance of the A4 error code on your heater are as follows:

• The combustion sensor is dirty or damaged: This can occur due to prolonged use of the heater, the presence of dust or dirt in the environment, or physical impact or deterioration.
• The wiring or electrical connection of the combustion sensor is in poor condition: This may be due to a power supply failure, improper heater installation, or a short circuit or overload in the system.
• The heater's electronic PCB (Printed Circuit Board) is damaged: This can happen due to an internal component failure, voltage surge or spike, or electromagnetic interference.

How to fix the A4 error in the Bosch heater?

Here is a list of tips and advice to help you resolve the A4 error code on Bosch heaters. You can try fixing this issue on your own without the need for technical support:

1. Restart the heater to reset the sensors: Sometimes, a heater restart can resolve such faults. To do this, turn off your heater completely and disconnect it from the electrical outlet for a few minutes. Then, reconnect the heater and turn it on to see if the error has disappeared.
2. Clean the combustion and/or ionization sensor with a soft, dry cloth: Locate the sensor inside the heater (usually near the burner) and carefully remove it. Clean it thoroughly with the cloth and, if possible, with a little isopropyl alcohol or electronic cleaner. After maintenance, reattach the sensor as it was and turn on your heater to check if the error has disappeared.
3. Check the wiring and electrical connection of the combustion sensor: Disconnect the heater from your home's electrical network and verify that the cables are securely attached and show no signs of damage or wear. Also, check the internal wiring of your heater and ensure that these cables are not cut, torn, burnt, or scorched. If you find any issues, replace the faulty cable or connection and then check if the error has disappeared.
4. Inspect the electronic PCB (Printed Circuit Board) of your heater: If you have knowledge in electronics, you can use a multimeter to check the connections and components of your heater's electronic PCB. Make sure that the values displayed by the multimeter are appropriate, and if you encounter any problems, you may need to find a replacement for your heater's electronic board.
5. Repeat all the above steps if the problem persists: You may need to perform a second review of everything we have described earlier. If, after repeating all the above actions for the second time, the error continues to appear, there may be a more complex issue with the heater.
6. Seek Bosch technical support to resolve the problem: If none of the above solutions work, it is best to contact a qualified professional to inspect your heater. We are confident that Bosch's technical staff will help you find a definitive solution to this problem.

In summary, the A4 error code means that there is a problem with the combustion and/or ionization sensor of the Bosch heater. The possible causes of this problem are: Dirt or damage to the sensor, defective wiring or electrical connection, or a faulty electronic PCB. The possible solutions to fix this issue are as follows:

• Restart the heater to reset the sensors
• Clean the combustion and/or ionization sensor with a soft, dry cloth
• Check the wiring and electrical connection of the combustion sensor
• Inspect the electronic PCB of your heater
• Repeat all the above steps if the problem persists
• Seek Bosch technical support to resolve the problem

We hope this article helped you understand and resolve the A4 error code on your Bosch heater. We are confident that good preventive maintenance will help you avoid such situations in the future. Good luck and until next time!