BoilerBuddy · Source-backed catalogue
Ferroli fault-code guides
Source-backed fault-code guidance for the verified Optimax 25 S range.
Source-backed catalogue
Verified boiler fault-code guides
Choose a supported model and code to read the catalogue entry and its source documents.
Ferroli · Optimax 25 S
- Ferroli F1The manual groups F1 with F3 and F8: no communication between the electronic unit and gas valve.
- Ferroli F2Flame detected while the burner is off.
- Ferroli F3The manual groups F1 with F3 and F8: no communication between the electronic unit and gas valve.
- Ferroli F5Fan problem.
- Ferroli F8The manual groups F1 with F3 and F8: no communication between the electronic unit and gas valve.
- Ferroli F25Software fault.
- Ferroli F30Delivery sensor fault: sensor damaged or short circuited.
- Ferroli F31Delivery sensor fault: sensor damaged or wiring broken.
- Ferroli F34Supply voltage under 190V or over 250V.
- Ferroli F35Irregular mains frequency.
- Ferroli F36Electronic CVBC trouble.
- Ferroli F37Incorrect system water pressure.
- Ferroli F43Return sensor fault: sensor damaged or wiring shorted.
- Ferroli F44Return sensor fault: sensor damaged or wiring broken.