What does the Ariston S 01 fault code mean?

Your boiler tried to light the burner but couldn't detect a flame, so it is currently not providing heating or hot water.

How much does it cost to fix Ariston error code S 01?

Typical repair cost for the Ariston S 01 fault is £100-250 including labour.

Check if other gas appliances, like a hob, are working to ensure gas supply is active

Flame not detected on first attempt

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.

Older boilers — thermocouple, draught, gas supply.