While you wait for answers, we may have found some information which could help you.
Click here for Boiler Gas Workingsaunier duval boiler problem?
How to repair F4 code?
Saunier Duval Thema F23 anyone have a link for manual?
Saunier Duval timeclock not working?
saunier Duval is over pressurising when the heating is on. ?
Saunier Duval Isofast condens F35E....nothing working?