F12
FAULT CODE
Ideal
Flame Loss During Operation
High Severity
Engineer Required
The boiler had a stable flame but lost it during operation. This can be caused by gas supply interruption, wind effects on the flue, or a failing gas valve.
Cold Weather Note
High winds can cause momentary flame loss. If it happens only during storms, a flue guard may help.
Step-by-Step Fix Guide
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Step 1
Check if other gas appliances are working to rule out a supply issue
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Step 2
Check the external flue terminal for wind exposure or blockages
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Step 3 Engineer only
If the fault keeps recurring, a Gas Safe engineer should inspect the gas valve and ignition components
Gas Safe Reminder
Work on gas appliances must be carried out by a Gas Safe registered engineer. The steps above cover safe checks a homeowner can perform - any internal component replacement requires a qualified professional. If in doubt, always call an engineer.