BoilerFaultCodesIntergas F004 Fault Code
The Intergas F004 fault code means: your boiler is failing to light the gas flame required to provide heating and hot water.. It appears on 5 Intergas models in our database.
Technical description: No flame during start-up.
What causes the Intergas F004 fault?
This fault occurs when the boiler's control system attempts to start the combustion process but cannot detect a stable flame. The most common reasons are a lack of gas supply to the unit, a worn-out ignition spark, or a build-up of carbon on the internal probes that monitor the fire. Without a confirmed flame, the boiler stops for safety reasons to prevent unburnt gas from entering the system.
This fault can occur more frequently during the first cold snap of autumn when internal components that have been dormant all summer are suddenly required to work under high load.
DIY fix possible
Check if other gas appliances, like a cooker, are working to confirm gas supply is active.If you have a prepayment meter, check that there is enough credit.Ensure the condensate pipe (the plastic pipe outside) hasn't frozen in cold weather.Try resetting the boiler by pressing the reset button for a few seconds.
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Gas Safe Register →Intergas models that show the F004 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Intergas F004 fault code information on this page is sourced and cross-checked against the official Intergas service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026