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Find clear guides to boiler error codes, common faults and everyday problems, with simple steps to pinpoint the cause and fix it faster. Save time with practical help that explains what each warning means and how to act without guesswork. Ideal when you need a quick, easy solution and want to get your boiler working again.
The D15 points to the sensor in the buffer-reserve tank and may affect the system’s heating performance.
The fault points to an internal communication failure. Connectors, moisture and vibrations are often behind the lockout.
The boiler loses its temperature reference and regulates less accurately. These are the causes, the actual extent of the issue, and the proper inspection.
The D12 alarm usually points to the room sensor or its wiring. Find out how it affects the heating system and when it is worth having...
The boiler loses the reference from a sensor and regulates less accurately. Here’s how to interpret the warning, what to check and when to have it...
The alert is usually linked to the domestic hot water sensor and requires a technical inspection to prevent further damage.
The boiler loses its outdoor reference and modulates less effectively. Key points for identifying the cause and preventing further damage.
Fault in the outlet sensor or its connection: how the boiler behaves and what inspection it needs.
The fault points to the circuit outlet sensor and may leave the three-way valve without control.
The warning indicates an internal fault in the SU electronics and requires a technical inspection to prevent further damage.
The boiler goes into protection when it detects flame loss: gas, ionisation, ventilation and electronics point to the cause.
An internal communication fault can stop the boiler and leave useful clues for diagnosis.