What does the Vaillant F.93 fault code mean?

Your boiler has detected that the fuel-to-air mixture is incorrect, which means it cannot burn gas safely or efficiently.

How much does it cost to fix Vaillant error code F.93?

Typical repair cost for the Vaillant F.93 fault is £150-300 including labour.

Manufacturer manual

Poor combustion quality

From this model's manual

Verified against the Vaillant/Vaillant Ecotec Plus 826 installation & service manual, page 51.

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

Boiler cover options

A cover plan would handle faults like F.93: no call-out fees, no surprise bills.

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

Older boilers — thermocouple, draught, gas supply.

Safety-critical — turn off, read this.

7 signs repair isn't worth it anymore.