BoilerFaultCodesIdeal 6C Fault Code
The Ideal 6C fault code means: your boiler is still detecting a flame even after it should have turned off, which suggests gas may still be flowing into the unit when it shouldn't be.. It appears on 1 Ideal model in our database.
Technical description: Ionisation occurs when heat is no longer required, the gas valve does not close.
What causes the Ideal 6C fault?
This fault occurs when the boiler's sensors detect heat or a flame after the heating cycle has finished. The most common reason is a mechanical failure in the gas valve that prevents it from closing fully, or a faulty sensor that is incorrectly reporting a flame is still present. Because the boiler believes gas may still be burning when it should be off, it will shut down immediately for your safety.
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 →Ideal models that show the 6C fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 6C fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026