Hey, weezard! Glad to hear from you again, buddy. I don't have a scale where I'm at (my house), but I estimate the rig dry is about 3.3lbs.

I was thinking the same thing on the small pipe. balloon, plug or vertical outlet. The vertical outlet I put on hold as the pressure, while not high, might still push water out the pipe, right...? I have a lot of plastic tubing to go on the pipe, though. I don't know exactly know how that would work with no air-intake and all... Might be a possibility. Now, that I'm thinking about it a balloon might be the thing. It might inflate a little, but it should stay small, right? Hm, hard to imagine how this works... With a finite amount of matter inside a closed space... The vertical outlet idea should work like when you put a straw into the coke bottle and pull it out with your finger on the air-end, though... but, maybe the pressure pushes the water out and lets air in and starts a siphoning-cycle, emptying the whole thing... I have no idea. What do you mean by "meat-thermometer" btw? didn't see that part before writing this paragraph.

Initially, I thought you meant the temp-switch would be a safety device, shutting down the whole thing if it had to... It's normally open, btw. But I would rather have it work like you described in your last post. Like you said, I assume the copper would be able to dissipate enough heat to work passively for some time (if that's what you meant). I should have ordered double and used both functions! I have been dreading the constant humming from the fan and pump, but your idea for the heat-switch would take care of that.

Water doesn't expand a lot before boiling point, if I got it right, so ~50 celsius is no problem, pressure-wise.

EDIT: I need more air in my posts