BoilerFaultCodesIntergas F15 Fault Code
The Intergas F15 fault code means: your boiler has lost connection with the sensor that monitors the outdoor temperature, which might cause it to heat your home inefficiently.. It appears on 3 Intergas models in our database.
Technical description: Outside sensor short circuit
What causes the Intergas F15 fault?
This fault occurs when the boiler can no longer receive a clear signal from the sensor located on your outside wall. The most common reasons are water getting into the sensor housing, or the electrical wiring becoming damaged or corroded due to exposure to the elements. Without this data, the boiler cannot automatically adjust its temperature based on how cold it is outside.
This issue often surfaces during periods of heavy rain or high winds, which can force moisture into the sensor casing or damage external cabling.
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 →Intergas models that show the F15 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Intergas F15 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