Bricoletta boiler

I’m having issues with my vacuum-breaker valve on my espresso machine boiler. It’s spurting a good bit of water all the time, instead of just letting out a bit of steam now and then.
I was going to remove and clean it, or replace it (it’s the rightmost hexagonal thingy in the picture). But after talking to Angelo at Espresso Parts Source, it may just be that my boiler is overfilled leaving no room for steam to do its magic.
The cause of this is either an easy fix (my water pressure going in may be too high) or something expensive. Crossing fingers now.