BoilerFaultCodesVokera d2 Fault Code
Also written as D2 — same fault.
The Vokera d2 fault code means: your boiler has detected an issue with the sensor that monitors the drainage of condensation water, which may prevent the unit from running safely.. It appears on 4 Vokera models in our database.
Technical description: Appears if a problem exists with the condense sensor.
What causes the Vokera d2 fault?
This fault occurs when the boiler's safety sensor detects that the acidic water, known as condensate, is not draining away correctly. The most common reason is a blockage in the internal condensate trap or a buildup of debris around the sensor itself, which triggers the system to stop as a safety precaution. In some cases, the sensor may have failed electronically or the wiring connecting it to the main control board has been damaged.
This fault is more common during extreme cold snaps, as the external portion of the condensate pipe can freeze, causing water to back up into the boiler.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Vokera models that show the d2 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Vokera d2 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