Hi, I expect Dave has waited for me to get to the forum as I disassembled that and took photos. In my case with the valve sticking to about 115c before shutting off but steaming just fine. I’ve had a crazy week inside and outside of work and finally I can get a few minutes here.
This is the vacuum breaker base which is at the bottom of that assembly
The stainless steel fitting sits on top and inside is a small separator with two springs, the short one is memory metal.
This photo from left to right is the orientation you must have from bottom to top ie. long spring inside base, separator then memory spring into the top stainless steel part.
That’s the best I can describe it but you’re in good hands with Dave and the more technical folk here.