While you wait for answers, we may have found some information which could help you.
Click here for Saunier Duval F24esaunier duval boiler problem?
How to repair F4 code?
How can I fix my Saunier Duval Semia Condens boiler?
I have a Saunier Duval Isotwin condens F 35 E with hot water No heating?
Saunier Duval Thema F23 anyone have a link for manual?
Saunier Duval timeclock not working?