Ferroli · Optimax 25 S
F5 boiler fault code
Optimax 25 S
Get a Gas Safe engineer
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Renting? Report it to your landlord or housing provider first. They are responsible for gas safety and boiler repairs, and the repair should not cost you.
What F5 means
Fan problem.
Safe check
Record F5 and note any unusual sound from outside the boiler. Do not open it or inspect the fan.
When to contact an engineer
Contact a Gas Safe registered engineer if the code appears or returns; fan diagnosis requires internal work.
Safety notice
A boiler fault code alone is not a gas or carbon-monoxide emergency. If you smell gas, a CO alarm sounds, anyone feels unwell, or there is an unsafe flame, leave and call 0800 111 999 from outside.
Source and provenance
- Optimax 25 S · reference 35446965 · code 3544696/5 · troubleshooting table, printed p. 26
instructions for use, installation and maintenance
05/2005 · code 3544696/5