BoilerFaultCodesYour boiler has stopped working because its internal safety system detected that wastewater cannot be pumped away or an add-on component is unresponsive.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Response from accessory module or defective condensate pump is blocking burner operation
What causes this fault?
This fault occurs when the boiler is unable to safely discharge the acidic water produced during the heating process. It is typically triggered because an external pump used to move this water has failed, or the internal electronic module that communicates with that pump has developed a fault. To prevent water from backing up and damaging the internal components, the boiler automatically shuts down as a safety precaution.
This fault is more common during freezing winter temperatures, as the external pipework can freeze and cause the pump to overflow or fail.
DIY fix possible
Check if the external condensate pipe is frozen outside your homeInspect the condensate pump's power cable to ensure it is plugged inCarefully check if the wastewater pipe or drain is blocked
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