While you wait for answers, we may have found some information which could help you.
Click here for Pressure 5bar Water
Saunier Duval timeclock not working?
How to repair F4 code?
'f19' error report - Saunier Duval 'Thermoclassic' boiler?
saunier Duval is over pressurising when the heating is on. ?
isotwin condens f 35 e service menu codes?
Saunier D’uval therma classuc?