What does the Ariston 109 fault code mean?

Your boiler has detected that the water is circulating poorly or there is trapped air, causing it to shut down to prevent overheating.

How much does it cost to fix Ariston error code 109?

Typical repair cost for the Ariston 109 fault is £120-£350 including labour.

Check that the boiler pressure is between 1 and 1.5 bar on the gauge.

Clas net one / Clas one CombiClas system one

This is a high severity fault. Stop using the boiler and call 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.

Lockout fault with a reset-needed pattern.