What does the Ariston E03 fault code mean?

Your boiler has detected that it is getting dangerously hot even while it isn't supposed to be running, causing it to shut down for safety.

How much does it cost to fix Ariston error code E03?

Typical repair cost for the Ariston E03 fault is £120-£280 including labour.

Flow temperature over 100°C while boiler is not in operation (stand-by)

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.

Safety-critical — turn off, read this.

7 signs repair isn't worth it anymore.