After a number of disassembly/reassembly cycles to fix leaks in the expansion valves for both flowmeters, I finally found the right combination of sealants to leave me with a leak-free machine. I had a problem with one of the fittings (described in
this post), but I managed to get it sealed temporarily. I noticed that the valve body had a recessed seat that appeared to be meant to accommodate an O-ring. I popped an O-ring on the fitting, and there were enough of the threads left to get it to seat into the valve body. After reassembling, no more leaks. Yeah! No wonder I found so much teflon tape glommed-up around that fitting during the tear-down.
I dared to pull a couple shots with some cheap beans while dialing-in the grinder setting. Nothing picture-worthy yet, but encouraging results. I did find that the group was not heating-up correctly, and I realized this morning that I probably need to bleed the thermosyphon loop. On this machine the loop feeds off the boiler water, with the infeed coming from the same place as the hot water tap (the hx is not involved in the thermosyphon loop). There's a screw on each group that covers the far end of the loop. My plan is to loosen the screw, and turn on the boiler and allow the building pressure to force the air out and water in to the loop.
Polishing the SS is next. I started with wet sanding with 1000, decided that was too fine, so I switched to 600. Better, but I'll need to drop to 400 to get a couple heavily scuffed areas. Pictures to come.
Ross