C1 High

Vokera C1 Fault Code

The Vokera C1 fault code means: your boiler's main internal computer has detected a serious technical error and needs to be reset or potentially replaced by a professional.. It appears on 4 Vokera models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Fault code requiring PCB replacement or test restart
Typical repair cost £250-450 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Vokera models that show the C1 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Vokera C1 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 7 July 2026