Dialing in a La Spaziale at work - how to adjust pressure?

[bjlange]

Hi there folks, first time poster here and relatively new to the world of making espresso, though I've enjoyed drinking it for a while. My office has an espresso machine in the kitchen and as I've been getting more into espresso (and more into the office) I've kind of become its adoptive caretaker. From the best I can tell from googling around and trying to dig up user manuals and such, I think it's a La Spaziale Special EP, a 2 group heat exchanger machine. Here are some shots of it, including from when I took the top and back off to look inside.






I've been trying to dial it in and have been having trouble getting consistency in the shots- either they're on the sour side, or as I have made the grind finer, sometimes it will pull decent ones and other times they're definitely "off". I unfortunately don't have a bottomless portafilter for the machine so can't directly observe. The grinder is a Mazzer Super Jolly so I don't think the grinder is the issue, and I know the coffee is fresh and good quality as we just ordered it and I've had the same beans at the coffee shop across the street and they're tasty.

Based on what I've read, I'm wondering if pressure is the issue- the gauges on the machine read 1.1+ bar for boiler pressure and up around 10 or 11 bar on the other gauge (pump pressure?) when pulling a shot.



What do you think- likely culprit? Anything else I should try or isolate? And if pressure is the problem, how do I go about adjusting on a machine like this? Do I adjust the boiler pressurestat or something else?

[Jeff]

Fun machine to learn on, even more fun to have available to you at work!

Welcome to H-B.

As it is a heat-exchanger unit and you're not pulling shots every 40 seconds in a cafe, have you been managing the brew temperature?

Though I'm not familiar with that model, most HX machines in "home" use need some kind of flush routine to keep the temperature within reasonable bounds shot-to-shot.

One place to start is Managing the Brew Temperature of HX Espresso Machines

More linked at FAQs and Favorites

[JRising]

While I'd suggest that "sour" can often be related to brewing temperature too cool, I do agree with you that adjusting your pump's maximum pressure down a bit might help make the machine a bit more lenient.

In your pic that includes the pump, I can make just make out the threaded adjustment part of the Pump Bypass Valve. By loosening the threaded part (red arrow) you will lower the pressure at which the pump's output is allowed to escape back to inlet, thus limiting the maximum pressure at which it can force water into the brew circuit.

See what results you get adjusting it down to 9.2 or 9.5, you can always turn it back if you don't like the change.
If the shots are still consistently sour as you try a few at the slightly lower pressure, then my thoughts jump back to temperature.

Simple ways to judge the temp of the brew circuit water in a HX machine include letting it idle for 15+ minutes and then hitting the brew button without a portafilter locked in. Watch the shower screen (from a distance) when you hit the brew button. If the first several seconds are an out-pouring of steam, that's normal, It indicates that the Heat Exchanger is properly heating the brew circuit water, and over-heating it if allowed to idle. After the cooling flush (after letting out the expulsion of steam) your brewhead will be barely below boiling temp and the (now liquid) water will be leaving the head fairly close to being at the temperature you want for brewing.

If you aren't getting the super-heated heat exchange water after 15 minutes (ie, it doesn't need a cooling flush to dispense liquid water), then I strongly suspect calcium build up on the heat exchanger, inside, outside or both. The mineral build up will insulate the Heat Exchanger and water in it and flowing through it won't be gaining as much heat from the boiler as it should.

That's enough for this morning. Good luck.

[bjlange (original poster)]

Yep, that's a good idea, and thanks for the links. I didn't even realize it was a heat exchanger until I opened it up Friday and thought "wow that's a big boiler.. and there's only one!". Not sure what will be the same and different compared to a small one but will definitely experiment with flushing and see what that does.

[bjlange (original poster)]

WOW, didn't see your reply when posting mine @JRising. Super helpful, thanks!

The good news- following your instructions I was able to adjust the pump pressure down to just a bit over 9 bar. The bad news- it started leaking from the adjustment nut so I had to disconnect and drain it. I'm guessing it's an issue like this: Rotary pump leak. Hopefully a new oring will resolve that..

While it was up and running, I can say that when hitting brew without a portafilter, liquid water comes out pretty quickly, almost immediately. Hot enough to steam as it hits the drip tray, but still definitely liquid.

Anyway I'll need to fix the drip and try out some different things at the new pressure to see where things stand.

[bjlange (original poster)]

OK! So we replaced the adjustment nut assembly and the good news is- it doesn't leak anymore.

The bad news is, shortly after I switch it on, the machine now makes a "clicking" or "ticking" noise. Here's a video of it: https://drive.google.com/file/d/18129IG ... sp=sharing

Any idea what this is? I thought it might be the pressurestat but I tried adjusting that and it didn't stop, and when I took the cover off and watched it, I didn't see it switching on and off. The boiler gets hot and the machine produces steam and hot water from the tap, though I haven't been able to get the groupheads to dispense water when I press the brew buttons.

[JRising]

That's your pressostat working properly. Run it with the pressostat open and see exactly how and why it works, spring loaded copper contacts being forced overcenter by the diaphragm beneath opens the contacts, electricity stops flowing through the element and the boiler stops heating. (Black box in the top right corner in the video, it will work with the box open so you can see).

[bjlange (original poster)]

For posterity's sake, in case someone else encounters a similar issue. (you never know when your thread ends up in someone's Google results!)

I ended up calling in a pro to help after struggling with this for a while. The clicking sound was in fact not the pressurestat, it was one of the solenoids clicking open and closed. It ended up being that another one of the solenoids had shorted and fried the logic board, which was on the fritz and clicking the solenoids open and closed like a clock. New logic board, new solenoid coil, and things are back on track. AND the pressure is now a couple bar lower, leading to the first consistently tasty shots I've pulled on this machine. A happy ending!