While you wait for answers, we may have found some information which could help you.
Click here for Boiler Combi Pcbisotwin condens f 35 e service menu codes?
Saunier Duval Isofast condens F35E....nothing working?
saunier Duval is over pressurising when the heating is on. ?
Saunier D’uval therma classuc?
Saunier Duval timeclock not working?
Saunier Duval Thema F23 anyone have a link for manual?