BoilerFaultCodesGlow-worm F.25 Fault Code
Also written as F25 — same fault.
The Glow-worm F.25 fault code means: your boiler has detected that the flue gases are getting too hot or that a safety connection inside the unit has come loose, causing it to shut down to prevent damage.. It appears on 20 Glow-worm models in our database.
Technical description: Safety shutdown: Flue gas temperature too high - Break in plug connection for optional flue gas safety cut-out (SCO), break in cable harness
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Glow-worm models that show the F.25 fault code
Click a model for the full fault code list and model-specific repair notes.
- 30cxi Repair: £150-£450
- 38cxi Repair: £120-350
- Betacom4 Repair: £150-300
- Compact Repair: £150-350
- Easicom3 Combi Repair: £150-300
- Easicom3 System Repair: £120-250
- Energy Repair: £150-350
- Energy Regular Repair: £150-300
- Energy System Repair: £150-300
- Energy7 Combi Repair: £150-350
- Energy7 Regular Repair: £150-300
- Energy7 System Repair: £150-350
- Essential Repair: £150-350
- Flexicom 24c / 28c Repair: £150-350
- Flexicom CXi Repair: £150-250
- MicraCom Repair: £150-350
- Sustain 12s Repair: £120-350
- Ultimate 3 25R Repair: £150-350
- Ultimate3 Combi Repair: £150-350
- Ultimate3 System Repair: £150-350
Source
Glow-worm F.25 fault code information on this page is sourced and cross-checked against the official Glow-worm service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026