6C (308) - After switching gas off: Flame is detected

What does 6C mean?

This fault indicates a dangerous condition where the boiler detects a flame even after the gas supply has been commanded off. This is a severe safety lockout.

• Gas valve failure, not closing completely to cut off gas supply
• Faulty flame detection electrode or circuit providing a persistent 'flame on' signal
• Defective electronic board (PCB) misinterpreting signals
• Incorrect gas pressure or combustion chamber issues

Click steps to track your progress.

1. 1

   Immediately turn off the main gas supply to the boiler and switch off the boiler's electrical power at the breaker. Do not attempt to operate the boiler.

2. 2

   Do not try to reset the boiler or restore gas/power until the issue is professionally assessed. This condition indicates a potential uncontrolled gas flow or ignition.

3. 3

   Check for any distinct odors of gas around the boiler, which would confirm a gas leak or valve issue.

4. 4

   Contact a qualified heating engineer or your gas emergency service provider immediately. This fault requires urgent professional attention for safety reasons.