What does the Vaillant F.65 fault code mean?

Your boiler’s control brain is overheating, which has triggered a safety shutdown to protect the internal electronics from damage.

How much does it cost to fix Vaillant error code F.65?

Typical repair cost for the Vaillant F.65 fault is £150-300 including labour.

Electronic temperature too high

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

Lockout fault with a reset-needed pattern.

Safety-critical — turn off, read this.

7 signs repair isn't worth it anymore.