BoilerFaultCodesViessmann E08 Fault Code
The Viessmann E08 fault code means: your boiler is unable to light because the internal fan is spinning too quickly for the system to safely start the ignition process.. It appears on 1 Viessmann model in our database.
Technical description: Burner does not start. Fan speed too high during burner start.
What causes the Viessmann E08 fault?
This fault occurs when the boiler's control system detects that the internal fan is spinning faster than the required safety limit during the start-up sequence. The most common reason is a communication error between the fan and the main circuit board, or a failure in the fan's internal speed sensor. Because the boiler cannot accurately control the air-to-gas ratio, it shuts down for safety reasons.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Viessmann models that show the E08 fault code
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Source
Viessmann E08 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026