Error F7

Safety precautions:

1) If you smell gas, leave the property immediately, do not operate switches or appliances, and call the national gas emergency number (UK: 0800 111 999) from a safe location. 2) Turn the boiler off at the electrical isolator if it is safe to do so and avoid repeatedly attempting resets. 3) Do not open the boiler casing or attempt to work on gas, ignition, or internal electrical components unless you are a Gas Safe registered engineer.

Initial checks a homeowner can do (no internal access):

1) Note the exact fault code (F7) and any three-digit cause code from the information menu if your display allows (press the spanner/return button). Record boiler model, serial and recent service history to tell the engineer. 2) Try a proper reset: either press and hold the boiler reset button for ~3 seconds or switch off the electrical supply at the isolator, wait 1–2 minutes, then restore power and observe. 3) Check for visible external flue obstructions (birds’ nests, debris) and ensure vents and flue exits are clear and not blocked. 4) Check for recent power cuts that might coincide with the fault appearing. 5) If the fault clears after reset, monitor the boiler; do not repeatedly reset more than once or twice — persistent re-lockouts indicate a real fault.

If the F7 fault remains after reset or returns intermittently: do not attempt internal repairs. Provide the following information to the engineer: F7 fault, any cause code shown, when it started, whether a reset cleared it temporarily, any strange smells, and whether the flue was blocked.

What a qualified engineer will check and potential fixes they may perform (for information only):

1) Inspect and test the ignition electrodes and leads for wear, contamination or damage; clean or replace electrodes and leads if required. 2) Test the flame sensor circuitry and continuity; replace a faulty sensor. 3) Inspect wiring and connectors between the electrode/flame sensor and the ignition module/PCB for loose connections or corrosion. 4) Check flue integrity and termination for blockages or installation faults that could affect detection. 5) Test the ignition/ignition module, gas valve operation and PCB outputs and inputs; repair or replace faulty modules or the PCB as necessary. 6) Verify gas supply and pressures only by a qualified engineer.

Final notes and when to call a professional:

1) Because this fault involves ignition/flame sensing and control electronics, call a Gas Safe registered engineer if the error does not clear with a single safe reset, if it recurs, or if you are uncomfortable with any step. 2) If you smell gas at any time, evacuate and call the gas emergency number immediately. 3) Provide the engineer with the fault code (F7), any cause code, appliance model/serial and any observations — this speeds diagnosis. 4) Do not attempt gas or internal electrical repairs yourself; these are specialist tasks and legally require a qualified engineer.