Worcester Bosch Boiler F7 Error Code — Meaning & Causes (2026)
Flame detected even though the appliance is switched off (ionisation before the burner starts). Below: what triggers it and what to check — this code carries no single repair to price. Reviewed July 2026.
What F7 means
Flame detected even though the appliance is switched off (ionisation before the burner starts).
Likely causes, most common first
- Faulty ionisation/flame electrode
- Leaking gas valve
- Control box fault
Base: 3 published national repair-cost guides (retrieved 2026-07) · full source registry on the methodology page · Code meaning & causes · Reviewed July 2026
No single repair to price for this code
F7 doesn't point at one failed component, so we don't attach a price module — forcing a repair mapping here would be dishonest. If the code keeps returning, the underlying symptom (not the code) is what gets priced: browse the boiler repair costs for the problem you're actually seeing.
Codes are universal — your location changes the repair price, never the code's meaning. See the methodology for the exact localization formula and sources.
Reviewed by a Red Seal–certified appliance technician who also holds a Technical Safety BC gas ticket (Gas-C) and an ODS/halocarbon refrigerant ticket (CFC/HCFC/HFC).