F7
FAULT CODE
Worcester Bosch
Flame Detected After Shutdown (Unsafe)
High Severity
Engineer Required
The boiler's ionisation circuit is detecting a flame signal when the gas valve should be closed. This is a serious safety fault requiring immediate attention.
Step-by-Step Fix Guide
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Step 1
Turn off the boiler immediately
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Step 2
Do not attempt to reset
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Step 3 Engineer only
Call a Gas Safe engineer immediately — the gas valve or ionisation electrode needs professional testing
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.