Thanks for all the great questions. I'll do my best, but there is still a bunch of metrology to do (I love that word). For those who care, a peek up her skirt (or his kilt):
NB: I had the two-element brass heater. I drilled out and removed the 200W heater and removed the heat shield. This improved circulation around the element (if that helps I have no idea why). The 200W heater was in the way of my TC, a 1/16" x 8" stainless grounded probe.
Operation goes like:
1. turn on gate valve to water. This lets cold water into the 20psi regulator (fixed, but I've got a better one on order).
2. power up the pid/heater and let heat.
3. because I live in fear of electrocuting myself, place measuring cup to catch group+opv drips.
4. at 50C, wiggle lever to check boiler pressure. if too high, close inlet water and drain by raising lever.
5. at temperature (95c at present), open inlet valve (bringing boiler to 20psi), and let 100ml run through head to pre-heat.
6. wait 1 minute (boiler may cool with inlet water, but comes back). pull shot.
5. (alternate) at temperature, open and close inlet valve, and let enough water run through the heat to pre-heat without exhausing the boiler pressure. keep inlet closed and use reduced pressure for shot.
I haven't been able to measure the puck temp, but taste is great and consistent. water in the measuring cup is 180f. I had plans to insulate the head, but I don't want to uglify too much. Maybe a wooden box around the head followed by spray-in foam. That would eliminate the heat-sink capability of the head. I also have a heater band that I might use on the head, but I think I'll wait. Pre-heating the head with a blank shot is sooo easy when plumbed-in.