I don't know about you guys, but I find having to babysit my machines a bit annoying. Cracking the steam wand to relieve "false pressure" in order to reset the pressurestat and allow the boiler to reach the set temp is surely part of the routine that I don't really care for. Also, having to remember to crack the steam wand again after the boiler cools is a bit of a pain.
I have a Riviera Espresso (Zacconi Baby) manual lever that I had modified previously by replacing the safety valve in the boiler cap with a Pavoni post-millenium safety valve. These have an integrated vacuum breaker and has allowed me to just turn on/off the machine without worry, (so long as there is water in the boiler).
I just got a Sama (Ponte Vecchio) Export to play with and wanted to do the same thing, but the LP safety assembly has gone up in price and may have a clearance issue with the top cover when installed with an adapter. During my research I noticed a post here that mentioned replacing the bolt on top of the sight glass, much like the pressure gauge mod for the LPE. It turns out to be a much more straightforward install than I had thought by just using an off-the-shelf vacuum breaker and keeping the stock safety valve on top of the boiler.
For posterity's sake, the thread is a 1/4" BSP. This is the part that I ordered for $15 off Amazon:
MacMaxe Universal 1/4" Anti-Depression Valve Vacuum Breaker for Espresso Machines
Here it is installed:
The Sama next to the Riviera: