Verified boiler fault code
Ferroli A15 Fault Code (i25 / i29)
Air-pressure-switch fault F05 generated five times in the last 24 hours.
Safety disclaimer
Fault code summary
- Manufacturer
- Ferroli
- Fault code
- A15
- Fault type
- Flue, Fan, Safety lockout
- Severity
- lockout
- Reset
- Ferroli states that A faults cause permanent shutdown and may be restored with RESET only after the fault is eliminated.
- Applicable models
- Ferroli i25, Ferroli i29
Quick answer
Air-pressure-switch fault F05 generated five times in the last 24 hours.
What does this fault code mean?
Air-pressure-switch fault F05 generated five times in the last 24 hours.
Common causes
- Repeated F05 air-pressure-switch fault.
Symptoms
- The display flashes A15 and the boiler permanently shuts down.
What can the homeowner safely check?
- Do not obstruct or dismantle the flue; contact a qualified engineer.
Boiler reset information
Ferroli states that A faults cause permanent shutdown and may be restored with RESET only after the fault is eliminated.
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
- Investigate the repeated F05 condition, pressure switch, fan and flue.
Applicable boiler models
Related fault codes
- A01 — i25 / i29
No burner ignition.
Read fault code - A02 — i25 / i29
Flame-present signal with the burner off.
Read fault code - A03 — i25 / i29
Overtemperature protection intervention.
Read fault code - A06 — i25 / i29
No flame after the ignition phase.
Read fault code - A09 — i25 / i29
Gas-valve fault.
Read fault code - A16 — i25 / i29
Gas-valve fault.
Read fault code - A23 — i25 / i29
Card parameter fault.
Read fault code - A24 — i25 / i29
Card parameter fault.
Read fault code
Manufacturer documentation
i25 / i29 Instructions for use, installation and maintenanceTable 9: A15 — Air pressure switch; fault F05 generated 5 times in the last 24 hours.
Last verified
2026-09-12
Frequently asked questions
What does Ferroli A15 mean?
Air-pressure-switch fault F05 generated five times in the last 24 hours.
Can I reset a Ferroli A15 fault?
Ferroli states that A faults cause permanent shutdown and may be restored with RESET only after the fault is eliminated.