Dear home-barista's! After almost a year of "sneaking" I finally registered to this forum, because I desperately need your help. Two months ago I bought a second hand Bezzera BZ07 (non-PID) with a matching grinder. Nothing seemed wrong with it, looked kinda new to me. Of course, I couldn't make decent espresso's straight away. So as any beginner I started with many, many trial and error, buying a calibrated tamper, La Marzocco VST filters and when I still couldn't get a decent tasting espresso I ended up buying a brand new grinder (Baratza Sette 270). However, after trying multiple freshly roasted beans, my shots still tasted sour. So I thought, if it is not the grind/beans, it must be the water temperature right? Whether or not this assumption is right here comes the real problem:
I decided to increase the boiler pressure on my machine. The factory setting was 1,2 bar, in little steps I adjusted the pressurestat with a flat head screwdriver till it reached 1,4 bar. I switched off the machine, put the body back on and switched it on again to make a test shot. However, before I was able to make this shot, the pressure dropped slowly but steady back to 0 bar and the water in the boiler won't heat up any more (so no water/steam coming out of the crane/steam tip)... which part have I broken? Please help!