What does the Main 3 flashes red fault code mean?

Your boiler is trying to start up but is failing to light the internal flame, which means you currently have no heating or hot water.

How much does it cost to fix Main error code 3 flashes red?

Typical repair cost for the Main 3 flashes red fault is £120-250 including labour.

Ignition fault (No ignition, No flame detected following ignition, False flame signal detected, Repeated loss of flame detected)

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.