Hi,

My Alex Duetto III is having a too high pump pressure when I am pulling a shot. It starts with 9/10 bar and then a new sequence starts and the pump pressure increases to 12 to 14 bar. Could the pump be defect? I have not tried to adjust the pump pressure as the pump seems to have two modes.

Very likely just needs the o-ring lubricated. If the o-ring is hard as rock, replace it.
(Talking about the o-ring inside the pump-bypass adjustment part of the pump, it's there to keep the pump from weeping out the breather hole, but when it gets sticky the valve stops being accurate).

At work, now... Can copy/paste pictures.
Part 18 is the o-ring in question, it goes around part 19.

Thank you! It fixed the problem