HVL87 It might be worth assessing the water level. That could be done by getting the steam boiler up to temp, then draining as much water out as possible via HW tap. Also noting whether the HW tap blows steam at the and rather than water just stopping and vac breaker opening.
The ml of water drained will indicate the boiler fill, and someone with a Minima machine on the counter can do the same and measure theirs