High
F4 on Viessmann Vitodens 111-W B1LD 35kW

The boiler tried to light its burner but couldn't establish a flame, so it has stopped and is waiting for a reset, which usually means no heating or hot water until it's checked.

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

Ignition, gas train opening or ionisation current build-up fails: fault F4 is displayed. Check the ignition module connection, gas train (230 V control voltage) and gas supply pressure, and electrode adjustment and gas line for airlocks.

From this model's manual
Verified against the Viessmann/Viessmann Vitodens 111 W B1ld 5697789 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

F0View →F5View →

All 28 fault codes on the Vitodens 111-W B1LD 35kW

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

0A0C1018303850515859A3A9b0b7b8E3E5F0F1F2F3F8F9FAFCFdFF

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