BoilerFaultCodesVokera 3x Fault Code
Also written as 3X — same fault.
The Vokera 3x fault code means: your boiler has detected a problem with how it vents exhaust gases or manages air flow, causing it to shut down for safety.. It appears on 3 Vokera models in our database.
Technical description: Fault codes 3x appear if the boiler or flue system has developed a fault.
What causes the Vokera 3x fault?
This fault occurs when the boiler's internal safety sensors detect that harmful exhaust gases are not being cleared from the system correctly. The most common reason is a failing fan that cannot spin fast enough or a blockage in the air pressure tubes that prevents the boiler from confirming the flue is clear.
This fault can be more common during periods of high winds, which can create back-pressure in the flue and interfere with the air pressure readings.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Vokera models that show the 3x fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera 3x 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