While you wait for answers, we may have found some information which could help you.
Click here for Saunier Duval F24eSaunier Duval Thema F23 anyone have a link for manual?
I have a Saunier Duval Isotwin condens F 35 E with hot water No heating?
saunier duval boiler problem?
Saunier Duval F35E auto-vents down to code 21 in minutes?
Saunier Duval Isofast condens F35E....nothing working?
'f19' error report - Saunier Duval 'Thermoclassic' boiler?