What does the Vaillant F.29 fault code mean?

Your boiler has lost its flame while running and cannot stay lit, meaning your heating and hot water will stop working.

How much does it cost to fix Vaillant error code F.29?

Typical repair cost for the Vaillant F.29 fault is £100-£350 including labour.

Check if other gas appliances, like a cooker, are working to confirm your gas supply is on.

Flame extinguished

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

Almost always a stuck diverter valve on combis.

Lockout fault with a reset-needed pattern.

Older boilers — thermocouple, draught, gas supply.