Any equipment may break. The main thing is to quickly and effectively eliminate the breakdown. To facilitate the task, the Bosch gas boiler generates errors on the display. These symbols indicate the cause of the malfunction. You just have to find the decryption and begin to search for the problem. And we will describe how to eliminate it below.
Features of the gas boiler Bosch
The dual-circuit device is the most popular among users. It simultaneously works for hot water supply (DHW) and heating. Some models are equipped with two heat exchangers, which ensure the smooth operation of the system.
On the control panel are power controls. Therefore, the heating can be adjusted to the area of the room. How does equipment switch from one circuit to another? A three-way valve is provided for this. The operation of the boiler is focused on the main circuit - heating. When the mixer is opened, the valve switches the flow to the domestic hot water system.
The circulation of the coolant is provided by the pump. Sensors control the device and, if there are deviations in operation, signal the control module. As a result, error codes appear.
Errors and malfunctions
The table contains error codes that correspond to the models Bosch WBN 6000-24C, Bosch ZSC 24-3 (35-3) MFA, ZWC 24-3 (28-3, 35-3) MFA, Bosch ZWE 24-4 (28- 4), ZSE 24-4 MFA, Bosch ZWE 24-5 MFK, Bosch ZWE 24-4 (ZSE) MF.
Error code | What does it mean | How to fix it yourself |
A2 | The combustion chamber is smoking. The heat exchanger is clogged with soot and scale. | Clean the radiator. Remove soot with a brush. The scale is removed by reagents or a solution of citric acid. |
A3 | There is no signal from the exhaust gas sensor. | Inspect the sensor wiring, tighten the contacts. Replace the defective part. |
A4 | Carbon monoxide goes to the stream fuse. | Clean the pipes and chimney from clogging with soot, debris, foreign objects. Check for traction. |
A6 | No contact with burner temperature sensor. | Diagnose the connections and the sensor itself. |
A7 | The water thermistor is out of order. | |
A8 | There is no contact with the BUS bus. | Tighten the connections from the bus to the control module. Replace cable |
A9 | Incorrect connection of the DHW temperature sensor. | Make sure the connection is incorrect. Install the element correctly using heat-conducting paste. |
AC | The module is not recognized. | Inspect the wiring between the module and the display, the information panel. As well as connections, an outdoor thermometer. |
Ad | No connection to the thermistor of the water heater. | Diagnose all contacts of the sensor. |
b1 | The system does not find the encoding plug. |
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C1 |
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C4 | The pressure switch does not work, does not open. | Diagnose and replace an item. When coding C6, additionally check the rotation of the fan. |
C6 | The relay does not close. | |
C7 | Faulty fan. | Reconnect the plug, repair the fan. |
CE | The pressure in the heating system has dropped. | Open the make-up tap. Top up the water until the indicators are normal. |
SS / d5 | The system "does not see" an external temperature sensor. | Connect the cable more tightly, make sure that the part is working. |
d3 | Jumper 161 is not fixed on ST8. | If the jumper is in place, connect the plug correctly. Contact the service center. |
d4 | Temperature difference exceeded. | Inspect:
Measure the pressure. |
d7 | The adjustment valve is out of order. | Diagnose the valve, its wiring. In case of malfunction, put in a new part. |
E0 | There is a problem with the circuit board. | Reconnect the contacts or install a work board. |
E2 | Flow thermistor is out of order. | Make the element ring for open, short. Check connectors for oxidation, clean and replace parts. |
E9 (11) | The signal from the heat exchanger temperature sensor. | What to do? Check:
Clean the radiator from scale and dirt. |
EA | The flame in the burner disappeared. | How to fix the problem:
|
er | Signal of failure of one of the nodes. | Perform a complete boiler diagnosis. |
F0 | Internal malfunction. | Inspect and reconnect the terminals and wires to the control module. Make sure their integrity. If everything is in order, change the module. |
F7 | The technique does not work, but the flame is determined. | Check if the chimney is working properly. Confirm the presence of traction. Diagnose sensors, electrodes, cables. |
FA | The fuel supply is shut off, but there is a signal of the presence of a flame. | Inspect the ionization electrode and the health of the valves. |
Fd | Random keystroke on a panel. | Press the same button and hold for 30 seconds. |
| | | Fan not adjusted. | Perform the adjustment. |
P | The type of boiler is not defined. | Set type. |
23 | Type of fuel indicated. |
Other malfunctions
In Bosch boilers, there are problems that are not displayed as an error.
Burner does not work
It is necessary to check the condition and turn on the emergency and starting switches. If one of the circuit breakers is faulty, repair it or replace it with a working device.
Also diagnose temperature controllers, outlet products relays. Perform preventive cleaning of the furnace, burner, nozzles, exhaust pipes.
No spark, no ignition
Look for the problem in:
- Ignition electrode. Strip it, place it closer to the burner.
- Burner.
- Ignition Transformer.
Noise and buzz when the boiler is turned on
Descale parts, including the heat exchanger, from scale. Salt deposits interfere with heat transfer, so water boils and hisses. If you do not remove the plaque, the node will overheat and fail.
Hot water does not turn on
If there is no hot water when opening the mixer, inspect the three-way valve. If it breaks, it must be changed. Also make sure the mixer is working, clean the pipes and filters from blockages.
Whistle when igniting the burner
The nozzle size does not match the pressure in the gas line. Change them.
Black smoke and soot
The ignition unit needs to be cleaned. Parts and holes clogged with dust and dirt.
Claps, ignition noise
What could have happened:
- Incorrectly configured gas supply.
- Incorrect nozzle size.
- The chimney is clogged.
- Incorrect chimney structure.
- Poor ventilation in the room.
We hope that by reading the article you will determine the cause of the breakdown. You can carry out repairs yourself if you understand the technique. However, remember: before starting work, it is necessary to shut off the gas and water supply.