3 flashes red High

Main 3 flashes red Fault Code

Also written as 3FLASHESRED — same fault.

The Main 3 flashes red fault code means: 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.. It appears on 1 Main model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Ignition fault (No ignition, No flame detected following ignition, False flame signal detected, Repeated loss of flame detected)
Typical repair cost £120-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Main models that show the 3 flashes red fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Main 3 flashes red fault code information on this page is sourced and cross-checked against the official Main service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026