Vokera syntesi 29 e code 03

[AideyJ]

Been working on of these recently and still getting 03 code on the central heating side, checked siphon, fan, venturi and flue all ok. Anyone got any other ideas?

 

[aggis]

03 could be aps,
It's an analog type, aps, not the same as the Linea.
If that doesn't sort it, it could be the pcb, but I'd contact vokera technical