What does the Atag C 20 fault code mean?

Your boiler is struggling to detect the flow of water through the system, which means it has safely shut down to prevent overheating.

How much does it cost to fix Atag error code C 20?

Typical repair cost for the Atag C 20 fault is £150-250 including labour.

Flow sensor error (e.g. open, short circuit, outside of range)

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.

7 signs repair isn't worth it anymore.