A flashing display does not necessarily identify a part to replace. On a Junkers or Bosch boiler, the message must be interpreted alongside the appliance reference and fault context. A good description helps the professional prepare the visit.
Start with the complete code and model
Photograph the display if accessible and record the exact letters, numbers, symbols and any subcodes. Find the designation in your documents or on a visible label. Do not remove a cover to find a reference. Also say whether the appliance provides heating only or hot water too.
Bosch Belgium’s documentation portal includes manuals for Bosch and Junkers ranges. Choose your exact model and the user section. A manual for another model, even one that looks similar, may describe different controls.
Describe what still works
Separate the functions when preparing your call. Do radiators heat up? Is hot water available at every tap? Does the message appear at startup or after a few minutes? These details are more useful than a conclusion such as ‘the circuit board is dead’.
| Observation | Information to provide |
|---|---|
| Occasional shutdown | Timing, frequency and time before the fault returns |
| Heating alone unavailable | Displayed mode and thermostat demand |
| Hot water alone unavailable | Affected outlets and observed behaviour |
| Recent event | Power outage, building work or latest intervention |
Consult the manual before resetting
Some appliances distinguish information, maintenance and fault messages. Bosch’s code finder lists possible causes for relevant equipment; a list of possible causes is not an on-site diagnosis. Always check that the result matches your appliance and its market country.
If the user manual allows a reset for the recorded message, follow only that procedure under the stated conditions. If the fault returns, keep the code and request a repair visit. Repeated resets are not a repair and may obscure the sequence of events useful to the technician.
An exterior check is still only an observation
Read only indications accessible without dismantling: display, schedule, summer or winter mode and any pressure reading. Report the value without assuming it suits every system. For filling or adjustments, follow the manual and professional’s instructions.
Prepare an effective repair enquiry
A useful example is: ‘Home in Schaerbeek, boiler reference attached, code visible since this morning, heating unavailable but hot water still working. Nothing dismantled.’ This is a sample description, not a customer case. Add the work address, a reachable telephone number and access availability.
Ask about travel and diagnosis terms before confirming. If a part is needed, clarify its reference, availability and expected cost. Keep the report to connect any recurrence with the previous intervention.
Situations that change the priority
If you smell gas, do not investigate the fault. Avoid flames and operating electrical equipment, leave the building and call Sibelga on 0800 19 400 from a safe area. Follow official instructions. Explicitly report water leaks or unusual noises too; do not touch internal appliance components.
Useful sources and guidance
Sources consulted on 14 October 2026. For regulatory obligations or operating procedures, check the version applicable to your installation.
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