The German company Bosch offers the consumer a wide range of gas boilers. A variety of options allows you to use the company's products in a variety of conditions.
All Bosch products have a common feature - in the event of problems in the operation of the boiler, alphanumeric codes appear on the information display. They are exactly the same for all models. Today we’ll talk about the main malfunctions and error codes of Bosch gas boilers.
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More about Bosch boilers
Although the company offers a wide range of gas boilers, double-circuit boilers are the most popular.
They got their name due to the fact that the liquid inside the device circulates through two independent circuits:
- heating;
- water heating.
Thus, the device allows you to maintain a comfortable temperature for a person in the cold season, as well as heat water for domestic use. This is the best option for private houses that are not connected to central heating and hot water systems.
The popularity of Bosch products is due to several factors:
- economical gas consumption;
- simple installation (relative to devices from other manufacturers);
- almost silent operation;
- simple maintenance;
- no need to equip the boiler room;
- long service life.
All modern models are equipped with an information display. It displays basic information related to the operation of the equipment: temperature, mode, pressure in the system. And in the event of a problem, an error code appears on the display. Sometimes there is no decoding of such codes in the instruction manual.
Basic error codes for Bosch gas boilers
Let's analyze the most common error codes that may appear in gas boilers from a German manufacturer, and also talk about how to fix the problem that they signal.
A3
Indicates that the control unit does not see the smoke sensor. Evidence of:
- part failure;
- short circuit on the wires leading to it;
- problems with the control unit.
To eliminate it, it is necessary to check the sensor itself and the wires leading to it, eliminate the short circuit or replace the part.
A8
Indicates that there is no contact with the BUS bus. To eliminate it is necessary to check the contact cables, as well as regulators. Usually the reason for the appearance of the code is a violation of the integrity or breakdown of one of the indicated components.
IN 1
The coding plug is not recognized. In most cases, the situation is due to insufficiently tight installation of the plug. To eliminate it, you need to install it so that it provides contact. In some cases, the problem occurs due to a malfunction of the plug itself. Then they change it.
C3
The error is due to the release of exhaust gases in the combustion chamber. Most often occurs due to the appearance of soot or clogging. To fix the problem, you need to clean the camera.
On the ZWC MFA model, this error can be indicated by code A2.
SS
Appears if the control unit does not "see" the external temperature sensor.
May be due to:
- part failure;
- KZ on the way to her.
To eliminate it, you need to check the temperature sensor and the wires leading to it.
C6
Indicates that the air pressure switch is not closing.
Fix the problem in the following ways:
- Checking the chimneya. The reason may be the presence of foreign objects there (soot, cobwebs, and the like).
- Checking the tubes going to the relay. The device may not work if condensation has accumulated on them. Tubes must be wiped dry.
- Checking the relay for a short circuit. If the insulation of the wires leading to the device has melted, a short circuit is possible and, as a result, a malfunction of the equipment and code C6.
The error can be caused by manually changing the air fan mode to a less intensive one. In this case, you need to set the initial speed of rotation of the impeller.
CE
Most often appears on the Bosch Gaz model. Caused by a drop in fluid pressure in the system.
Solved as follows:
- when the pressure gauge is in the red zone simply increase the pressure in the system by increasing the water supply with a make-up tap;
- when the pressure gauge is in the green zone change the pressure sensor (with a high degree of probability, the error appears due to its malfunction).
C7
Indicates a fan failure. First of all, it is necessary to check for the presence of a short circuit in the wires that lead to the impeller. If they are in order, it is necessary to examine the fan itself - most likely, it is faulty. If the device is in order, the reason is the incorrect current supply from the control unit.
There can be two reasons for this:
- sensor malfunction;
- failure of the control side itself.
In the first case, change the sensor. In the second, it is better to contact the master.
D3
Talks about an unfixed jumper 161 on ST8. It needs to be put in place. If the jumper is already installed, you need to contact the wizard - most likely, the problem is due to a malfunction of the control unit.
D4
Reports a significant discrepancy in temperature data from different temperature sensors.
You need to check:
- circulation pump;
- bypass hose;
- total pressure in the system.
D5
Indicates that the external temperature sensor is defective. Requires replacement part. In some cases, it may be due to a short circuit on the wires leading to the sensor. In such a situation, it is necessary to eliminate the short circuit and restore the insulation.
E2
Faulty operation of the temperature sensor located on the supply line.
When the code appears, you must:
- check the integrity of the sensor;
- examine the wires leading to the device for a short circuit.
If there is no short circuit, the temperature sensor is intact, and the error still persists, then the part should be replaced with a new one.
E9
Indicates the operation of the temperature limiter (respectively, overheating in the heat exchanger).
However, it can also appear at normal temperature in the circuit - this happens if:
- the temperature sensor has failed;
- the wires leading to the temperature sensor melted, due to which a short circuit occurred and the sensor transmits incorrect information.
On some models, another code may appear - 11. It signals the same problem in the operation of the equipment.
To fix the problem you need:
- check the integrity of the wires leading to the temperature sensor, the sensor itself;
- increase the pressure in the heating circuit (the problem may be due to its drop);
- check for air in the system, bleed if necessary;
- check that the pump is working.
EA
Speaks of the absence of a flame in the burner.
To fix it, you need to check:
- gas supply;
- gas pressure in the system;
- connecting the boiler to the mains;
- condition of the ignition electrode, ionization electrode, wires leading to them.
FD
This code is displayed when the button is pressed and held for more than 30 seconds. Fixing the error is very easy. To do this, just press the button and hold it for less than 30 seconds. After that, the problem should disappear.
F0
Unexplained fault. This means that the boiler electronics “feels” that the device is functioning abnormally, but cannot identify the reasons for such operation.
Most often, F0 is due to problems with the equipment control unit.
Its reasons are:
- short circuits of wires due to melted insulation;
- short circuits due to the appearance of condensate on the board;
- the appearance of oxide on the terminal blocks.
Accordingly, it is first of all worth checking these particular structural elements.
FA
One of the most common mistakes in the operation of the boiler. Indicates the absence of a flame after the boiler is turned on.
It may appear for the following reasons:
- the gas supply valve is closed or not fully open;
- insufficient gas pressure;
- the voltage in the household electrical network has dipped;
- no traction.
Accordingly, in order for the error to disappear, all these circumstances must be eliminated.
The problem may be due to incorrect operation of the electronic control unit or a bad spark on the electrode during ignition.If the reason is precisely in them, then it is better to contact a boiler repair specialist
Summing up
About major faults Bosch gas boilers signal with alphanumeric codes that appear on the information display of the device. Most problems can be fixed on your own. The difficulty is that different models have different codes too (although not always). In addition, often their decoding is not available in the operating instructions for the device.
Video advice on how to fix the Bosch boiler EA error
Hello. I have a Bosch ZWA 24-2 A23 boiler. When hot water flows for 20-30 minutes, hot water suddenly turns off and the indicator flashes. Error not lit. What could be the reason ? Thanks