BoilerFaultCodesVokera b 26 Fault Code
Also written as B26 — same fault.
The Vokera b 26 fault code means: your boiler is unable to drain the water it produces during normal operation, which is causing it to shut down to prevent internal damage.. It appears on 1 Vokera model in our database.
Technical description: Condensate trap blocked
What causes the Vokera b 26 fault?
This fault occurs when the internal trap or the external drainage pipe becomes obstructed, preventing the boiler from safely disposing of the wastewater it produces during operation. The most common reason is a buildup of sludge and debris within the trap itself, or an ice blockage in the external pipework following a cold spell.
This fault is significantly more common during winter, as the wastewater in the external discharge pipe can freeze and back up into the boiler.
DIY fix possible
Check the white plastic pipe leading outside to see if it is frozen or blocked.If frozen, gently pour warm (not boiling) water over the external pipe to melt the ice.Carefully check the plastic trap underneath the boiler for visible blockages if accessible without opening the boiler casing.Restart the boiler once the blockage is cleared.
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Gas Safe Register →Vokera models that show the b 26 fault code
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Source
Vokera b 26 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