High
F11 on Vaillant ecoMAX Pro 18E

Your boiler's computer has lost the ability to communicate with its internal control sensors, so it has shut down as a precaution.

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.

Technical description

No reception by main board

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.

Find a Gas Safe engineer
Search the official register →

Related fault codes

Related guides you might find useful