Verified boiler fault code
Glow-worm F3 Fault Code (Flexicom cx)
Fan unable to reach ignition speed.
Safety disclaimer
Fault code summary
- Manufacturer
- Glow-worm
- Fault code
- F3
- Fault type
- Fan, Ignition
- Severity
- Not specified
- Reset
- Not specified
- Applicable models
- Flexicom cx
Quick answer
Fan unable to reach ignition speed.
What does this fault code mean?
Fan unable to reach ignition speed.
Common causes
This information was not provided in the verified manufacturer source.
Symptoms
This information was not provided in the verified manufacturer source.
What can the homeowner safely check?
This information was not provided in the verified manufacturer source.
Boiler reset information
Reset information was not provided in the verified manufacturer source. Do not repeatedly reset an unresolved fault.
When should I call an engineer?
Contact a suitably qualified heating engineer when the fault persists, the boiler locks out, or the manufacturer instructions do not resolve it. For gas appliance work in the UK, use a Gas Safe registered engineer.
Engineer diagnosis
Engineer diagnosis information was not provided in the verified manufacturer source. A qualified engineer should diagnose the appliance safely.
Applicable boiler models
Related fault codes
- F1 — Flexicom cx
Ignition fault.
Read fault code - F22 — Flexicom cx
Low water pressure or ignition temperature rise too slow.
Read fault code - F25 — Flexicom cx
Circulation fault.
Read fault code - F5 — Flexicom cx
Overheat fault.
Read fault code - F77 — Flexicom cx
Condensate pump error (optional).
Read fault code - F9 — Flexicom cx
Water pressure sensor fault, blocked flow filter or pump fault.
Read fault code
Manufacturer documentation
Fault finding codes for the Flexicom cx rangeF3 | Fan unable to reach ignition speed
Last verified
2026-09-12
Frequently asked questions
What does Glow-worm F3 mean?
Fan unable to reach ignition speed.