erics wrote:And all your video's are marked "private".

I don't know how to work the internet... Oh no--I'M OLD! Fixed.

The P.stat has a pretty wide swing (on at .7, off at 1 bar) so I was afraid to turn it down much more. But maybe I'll never miss the steam power--I'll definitely give it a shot and report back!

Here's a pic under the cowling; t-type TC installed in the grouphead screw trying to follow your (Eric's) placement instructions.


Here's a pic of the plumbing. I can try to get a better one if it's hard to pick out what you're looking at.


(Also, a few more pics in my rebuild thread here: VFA Expres two group E61 project... what IS this thing?!

Edit: The upper and lower group pipes are both 12mm (o.d.)

The upper and lower group pipes are both 12mm (o.d.)

Then, I just happen to have two thermosyphon restrictors for those lines . Send me an email at the address below my sig.

I've listened to all three videos multiple times. It's behavior reminds me a lot of when I had my Fiorenzato Bricoletta, definitely a Dragon HX! Though your idle group temp is about 10f higher than my Bric' was and hopefully the restrictors will help idle temp somewhat. Flash itself doesn't really sound too excessively long for a Dragon, 7sec from even long idle idle and then ~4sec next too.

Have you actually tried pulling shots yet? Since group idle rather hot with entire brew path over temp I wouldn't try a flush-n-go shot directly from idle state. For ~200f actual shot first from idle I'd flush until flash ended plus another ~20 sec = temp displayed hits 200f. Quickly build PF, flush to just end of flash and immediately count one-one thousand two-one thousand...six-one thousand lock and pull. Approximately one-one thousand count from flash reduces shot temp ~1f each count. (~206f actual shot which would likely be result if starting shot right at end of flash on back to backs.) Pulling back to backs next shot do the same thing: build PF, flush to end of flash down count lock and pull. You could do that non-stop all day and not have shot temps dive. Remember these suckers are designed for constant shot pulling not walk up from idle shots! Even with my Bric' I only needed ~35sec post shot brief group screen clearing flush to have brief flash for next flush-n-go shot.

Initially having an Eric's thermometer in my group helped dial in my Bric' shot routine. Also had a Scace Thermofiliter so of course this helped even more! Once I became accustomed to taming the Dragon listening for end of flash and down counting for pull just as effective and for me actually easier more intuitive. After a couple years the Eric's group thermo died and used Bric' another 5 years without it before upgrading to a DB machine no problem.

Compass Coffee wrote:I've listened to all three videos multiple times. ...

Wow, this is a lot more hits than I was expecting! I have actually been using the machine for about 1 1/2 yrs as-is and just living with the long flush, doing a routine very similar to what you described (i.e. long cooling flush, prepare PF, 2nd flush and go). One issue with this strategy is that the machine (and new sink next to it) actually drain into a 55 gallon drum in the basement--I still have to drill through the foundation wall in order to properly tie it into the sewer drain! If it wasn't for this, I might have never gotten around to complaining about the cooling flush. Heck, maybe actually finishing the drain connection would be easier than fussing with HX flush!

But, playing with espresso machines is a lot more fun than playing with demolition drills (up for debate I guess), so I have been messing around with washers made from a sheet of PTFE I found, drilling holes of various sizes. Idle temp is down to 208 deg with a 3.0 mm restrictor, yet the flush from idle still seems to take about the same amount of water. Successive flushes are much shorter. But, either temp stability has suffered, or I just haven't figured it out how to work with it yet to hit a certain or stable temp during the shot--it is always declining, climbing, or some of each. Also, I am concerned now that my temp might be diving too much for making successive shots at my next brunch party.

Maybe it is pulling too much cool water through the lower tube, so I wondered if I should add another restrictor in the lower leg to fine-tune the brew/flush flow (shouldn't affect thermosyphon flow or idle temp). In fact, with a PID and electronic flow valve balancing water flow from the top and bottom tubes, wouldn't you be able to fine-tune HX brew temp like a DB, or even adjust on the fly? Certainly somebody will have done this if it were "easy."

I keep thinking that somebody out there must have come up with at least an adjustable needle valve solution. Found this quote from Eric in an old thread:

erics wrote: There's other possible solutions also - maybe a Swagelok needle valve with three settings - ya know - (1) normal (2) dinner party (3) barista jam

I love it! Does anybody know of an appropriate Swagelock valve which I could solder into a new upper HX tube?

so I wondered if I should add another restrictor in the lower leg to fine-tune the . . .

I have never done that as most restrictors lie in the upper tube. There has been discussion re instability when messing with the lower tube but take that with a "grain-o-salt".

The restrictors I offered you are 2.50 mm and would suit this machine well.

Sorry if I am late to the discussion.

I have a Parker Instrumentation Valve (brass needle valve), angle style, with 3/8" compression fittings. This could be adapted for the purpose you are considering. I thought about using it with my Salvatore, but I don't have room inside my machine for a needle valve; it looks like your machine does. If you are interested, let me know.

The Salvatore has very little thermal memory and a lot of HX flushing is required to cool the group head to get in a range for decent shots. Even with the flushing, I found I needed to monitor the temperature of the upper thermosiphon loop to make sure the incoming water was neither too cool (didn't wait long enough after the flush) or too hot (waited too long after the flush). I used a surface attached thermocouple to observe temperature of the supply tube to the group head. I also have Eric's thermometer in the group head. This requires watching both temperatures for the best time to extract the shot.

I've moved on to using a PID temperature controller on the boiler to get a group head temperature perfect for brewing. For my machine, I am using 224*F for the boiler temp to get 204*F idle at the group head. I need no flush; I just put the loaded portafilter in and draw the shot. I still get a slight rise in group head temperature leveling back to ~204*F. To steam, I raise the set point to 240*F to get ~1bar pressure. This take less than a minute - so no problem. It takes about 20 min for the machine to return to 224*F after changing the set point back for brewing. This works for my personal needs. For a multiple extractions with steaming, I'd go back to the flush and go method.