We may have found other answers which could help you.
Click here for Air Pressure Expansionsaunier Duval is over pressurising when the heating is on. ?
Saunier D’uval therma classuc?
Saunier Duval timeclock not working?
How to repair F4 code?
'f19' error report - Saunier Duval 'Thermoclassic' boiler?
saunier duval boiler problem?