What does the Ariston A02 fault code mean?

Your boiler is failing to detect water flowing through the system, which means it cannot safely turn on the heating or hot water.

How much does it cost to fix Ariston error code A02?

Typical repair cost for the Ariston A02 fault is £150-300 including labour.

FLOW TEST FAILURE

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.

Each noise points to a different fault.

Sludge build-up — needs flushing, not bleeding.