Thanks Dan! I had previously thought the heat exchanger was just a simple tube. I wonder if my expobar has a relatively short injector, since it picks up heat very efficiently (long flush required, low rebound time).

I used a friend's Expobar Lever for a couple months; you aren't kidding - it requires an olympic-sized flush! A shorter injector may be part of the reason, plus other factors like the delivery tube length and diameter. I've not compared them carefully, but they look longer and larger in diameter than other E61s. That said, I had no trouble pulling good shots on it with appropriate adjustments to the flush amount (long) and rebound time (short).


From Odd Expobar problem - no thermosiphon

HB wrote:I used a friend's Expobar Lever for a couple months; you aren't kidding - it requires an olympic-sized flush!

No joke here. With the top of my deadband somewhere around 1.14bar, I have to flush 8oz and immediately lock in (or within about 10 sec) for any beans darker than City roast. If I do a few pseudo-shots as I prep my basket, I can sometimes lower the flush volume to 6oz, but this really works better with the lighter coffees.