My Giotto just developed a problem that I suspect is fairly simple to diagnose and fix, but I wanted to run it by y'all. Machine heats up, pressure goes to 1-ish on the dial, open steam valve and a big whoosh of steam comes out, pressure goes to zero. Close valve, within a few minutes the pressure is back up and the steam is adequate for texturing of milk. Is this likely to be the anti-vacuum/anti-siphon/vacuum breaker valve? While I'm ordering parts, should I also replace or upgrade anything (pump? pressurestat?)? I did recently backflush. Should I descale (last done about a year ago)? Anything else come to mind with this symptom?

Thanks, James

Sure sounds like a bad vacuum breaker, or rather a sticky breaker. You can take it off the boiler and soak it in some descale solution or vinegar to see if the problem clears up. If not, just put in a new vacuum breaker. They are relatively inexpensive. A couple group gaskets and a vacuum breaker are some of my standard spare parts.