BoilerFaultCodesGlow-worm F3 Fault Code
The Glow-worm F3 fault code means: your boiler has detected that the internal mechanism responsible for clearing waste gases is not operating correctly, so it has safely shut down to prevent unsafe operation.. It appears on 10 Glow-worm models in our database.
Technical description: Fan fault
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 F3 fault code
Click a model for the full fault code list and model-specific repair notes.
- 38cxi Repair: £180-350
- CXi / CSi Repair: £200-£400
- Jaguar Combi Repair: £180-350
- Ultracom 2 CXI Repair: £180-350
- Ultracom 2 HXI Repair: £150-300
- Ultracom 24cx 30cx Repair: £180-350
- Ultracom 35 Store Repair: £180-350
- Ultracom cxi Repair: £180-350
- Ultracom hxi Repair: £180-350
- Ultracom sxi Repair: £150-300
Source
Glow-worm F3 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