What does the Vaillant F.1 fault code mean?

Your boiler has failed to ignite and cannot produce heating or hot water because it isn't getting a gas supply or the internal spark is failing.

How much does it cost to fix Vaillant error code F.1?

Typical repair cost for the Vaillant F.1 fault is £120-280 including labour.

Check if your gas meter has credit (if using a pre-payment meter).

Lack of gas, a fault with the ignition or flue – may need to adjust the gas valve or replace a defective electrode lead.

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.