BoilerFaultCodesVokera 9x Fault Code
Also written as 9X — same fault.
The Vokera 9x fault code means: your boiler has stopped working because the waste water pipe is backed up or blocked, often due to freezing weather or a buildup of debris.. It appears on 3 Vokera models in our database.
Technical description: Fault codes 9x appear if the condense trap/pipe has become blocked.
What causes the Vokera 9x fault?
This fault occurs when the internal safety sensors detect that the waste water produced by the boiler cannot drain away. The most common reason is a physical blockage in the drainage pipe, which causes water to back up into the boiler's internal trap and triggers an automatic shutdown to prevent internal damage.
This fault is extremely common during periods of freezing weather, as the external portion of the condensate pipe can easily freeze and become completely blocked with ice.
DIY fix possible
Locate the plastic condensate discharge pipe leading outside your property.Check if the pipe is frozen and gently pour warm (not boiling) water over it to melt the ice.Verify if the external end of the pipe is blocked by debris or submerged in water and clear it.Restart the boiler by turning the mode selector switch to the 'reset' position.
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Gas Safe Register →Vokera models that show the 9x fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera 9x fault code information on this page is sourced and cross-checked against the official Vokera service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026