High
F4 on Viessmann Vitodens 100 Compact

Your boiler has failed to ignite or stay lit, meaning you currently have no heating or hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Check the connection ignition module / Check the gas train (control voltage 230 V) and gas supply pressure / Check the ionisation current, check the electrode adjustment and the gas pipe for air-locks.

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 100 Wb1a 13kw 18kw 24kw Compact Heat Only Installation Servicing Instructions Manual installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F2View →F5View →E4View →

All 19 fault codes on the Vitodens 100 Compact

Seeing a different code? Every code this model can display, in one place.

0b30386068b1b5E4E5F0F2F3F5F8F9FAFdFE

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