BoilerFaultCodesIdeal 406 Fault Code
The Ideal 406 fault code means: your boiler has experienced a direct failure of its main internal computer brain and cannot control the heating or hot water safely.. It appears on 2 Ideal models in our database.
Technical description: Internal failure - electronic
What causes the Ideal 406 fault?
This fault occurs when the boiler's internal computer chips or circuits suffer a physical breakdown, meaning the unit can no longer process data or send signals to parts like the pump or gas valve. The most common reason is general component fatigue over time, though it can also be triggered by a sudden electrical surge or moisture getting onto the control board.
This fault is slightly more common during winter or periods of heavy rain, as increased humidity or high electrical demand on the local grid can put extra stress on ageing electronic components.
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 406 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal 406 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