Well, I was about to report that I just wasted everybody's time, but I'm so amused by Jerry and Tim that it was worth it!
I won't go into what I just did out there (verifying open lines), but I have concluded that I had not screwed the canister lid on tightly enough. The gasket was in place, the washer is actually integrated into the spring in the lid, so can't be lost or omitted, and all I needed to do was tighten!
Now that I'm into that system, I will look for the hole that Jerry speaks of. Fascinating stuff.
