What does the Atag A1 fault code mean?

Your boiler has detected that the water returning from your radiators is too hot, causing it to pause heating to prevent damage.

How much does it cost to fix Atag error code A1?

Typical repair cost for the Atag A1 fault is £120-250 including labour.

Return water temperature

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Each noise points to a different fault.

Sludge build-up — needs flushing, not bleeding.

Almost always a stuck diverter valve on combis.