I have been toyeing with the idea of a "semi-pro" espresso machine for a long time. Previously I owned a small, the simplest KRUPS machine ever. Then, for the ease of use (so that parents can use it) I bought a Delonghi Magnifico 3000 automatic. And I have been constantly in search of a good deal for a better, more professional semiautomatic.

I was planning to learn the craft on it, and then maybe open a small coffee shop that would be aimed on the quality aspect of the coffee. Use the machine there (at the beginning the volume of visitors will be small, I predict). Then I would see how the things would evolve, and get a two-group LaMarzocco GB5.

With all this in mind, I acquired a used Promac Club PU 1-group, semiautomatic—in a good shape, after a year of usage, with approximately 3000 shots pulled.



It is a 4-liter, one-boiler machine, http://www.promacitalia.com/schede/green_club_eng.pdf (pdf, 545 kB). I have thoroughly cleaned the group head, changed the screen (was filthy you could not believe that water was still flowing through it), rubber gasket, cleaned steam wand, portafilters, backflushed it several times with Cafiza2 in course of two days—to really clean the baby up. Changed the chemicals in the de-calcifier.

I have noticed that the previous owner had a coffee-spillage inside the machine, on the metal panel near the front (missed the boiler, luckily). So I will have to clean it more inside. (yes, you guessed right, I am a cleaning freak when it comes to coffee)



Having no prior first-hand experience (only tons of reading and watching videos), I have spent the last few days trying to pull shots, get the right combination of grinds coarsness, learning to steam milk (using a soap in a water technique), and generally getting to know the machine and finding out what I might need. So far I see a need for a pressure-meter, termomether, good tamper, ridgeless double basket. Right now I have no idea what the pressure and temperature are, the boiler pressure shows 1.3 bar (19 psi). Also, I am not yet familiar with the insides and will need further reasearch before I begin substantial tweaking. I know only where: the temperature adjustments are made (black plastic box), and the pump pressure adjustment screw.

Right now, I think, the boiler pressure is too big. Or is it not? I might need to reduce it to 1,1 bar (can't microfoam milk—gets hot in like 12 seconds (0,3 liters volume of milk in a 0,75 liter pitcher), and the microfoam is only on the top, milk gains only 15% of volume by frothing). Are my assumptions on the too-high-boiler-pressure correct, or the problem is in my technique of frothing (inexperience)?

I will get back to this thread and post more observations and questions. Thank you for looking, and your ideas.

Fantastic first post! And welcome.

You're going to enjoy the step up to a more serious machine. Just to get it out of the way, there's a question to ask up front -

"what grinder are you using with the machine?" (Oh, and what beans?)

Also - I'm not familiar with the Promac - you say it's 4l, one boiler. Does that mean it's a one boiler, dual use machine? Or (I'd assume) a heat exchanger? Ah - I assume the boiler pressures you quote mean it's a HX

Steaming small volumes with a big machine is difficult - i'm finding it a steep learning curve, as everything happens quickly. Apart from technique, 2 things to think about are boiler pressure, but also the level of water in the boiler. (adjusting this will make your steam 'wet' or 'dry').

Good luck! I'm sure there'll be some more qualified posters along in a minute...

Thank you for the encouragement and warm words

triptogenetica wrote:"what grinder are you using with the machine?" (Oh, and what beans?)

I have Mazzer Mini Man, cleaned and with burrs "as they were new" (Mazzer technician's remark made a week ago). As a coffee I am using Brasilia Santos, roasted 3 months back... yes, I know. But for learning, I think it would suffice, and anyway, I want to finish it, so it does not sit on my shelf anymore.

triptogenetica wrote:Also - I'm not familiar with the Promac - you say it's 4l, one boiler. Does that mean it's a one boiler, dual use machine? Or (I'd assume) a heat exchanger? Ah - I assume the boiler pressures you quote mean it's a HX

I guess it is HX (I am not yet sure of the terminology and technology). I have been beefing up on espresso making technique up until several days ago, so I will have to catch up in the machines' inner parts, tweaking etc. In the other post (http://www.home-barista.com/espre...t9625.html#p110709) I have come upon a picture, and I think it is the boiler and group that are on the machine I own.


EDIT: I found another useful pic on http://www.home-barista.com/advic...-t3359.html#p36296 (http://www.partsguru.com/RancilioEspressoMachines.html)

triptogenetica wrote:Steaming small volumes with a big machine is difficult - i'm finding it a steep learning curve, as everything happens quickly. Apart from technique, 2 things to think about are boiler pressure, but also the level of water in the boiler. (adjusting this will make your steam 'wet' or 'dry').

I agree, I find it very difficult to do in such a short time. What I do with the steam now is this:
1) open the steam fully (without the wand being in the pitcher)—it lets out a burst of water for a second, then it is a wet steam for another second.
2) when the steam gets dry (almost invisible after 2-3 seconds) I close it and put the wand in the pitcher
3) open the steam again and froth away.

Good on you.

You will want to descale the machine I would imagine. I'm sure you'll find heaps of info on that if you search for it on this site.

Regarding the milk, it will most likely be lack of experience. Again, a good search on this site should yield results. For large boilers, depending on steam tip, I have found that centering the tip in the middle of the jug a centimeter or so below the surface is a good place to start. Turn on the steam, make a small 'tearing' sound with the steam tip close to the surface for a couple of seconds, then submerge it a little more so that it just rolls the milk. Ends up as a standing wave rolling in on itself. Hold it until its a little too hot to touch and stop. Mentally rehearse what to do and where your hands will go, as it happens quickly.

Read up on dosing, distribution and tamping.

And MAKE SURE YOU HAVE FRESH BEANS.

Good luck.

Your machine looks A LOT like a Rancilio S26 or EPOCA S1; almost identical components. This piece of info should help you since there are some discussions here and elsewhere on these machines.

With the above assumption, your machine holds ~100ml in the HX. I can't tell from your photos if you have a thermosyphon or not but I'd guess not based on what's visible from the photos. Your machine might(or not) have a flow reducer in the GH. Do one thing, measure how much water you get in 10secs (with no PF in the group) to verify. If you have one (a jet) your life should be much easier.

You got yourself a workhorse, no question about that. I'm guessing your steam tip has 3 or 4 holes. For easy steaming for smaller amounts of milk, you need to reduce this number to 2 holes. You either close the extra ones on your current tip or buy one with 2 holes.

Now, on brew temp and p-stat setting, your machine will tend to have a very cool GH temp and that will be a challenge for someone new to the machine. What I suggest you start with (till you get a feel for how this thing is different from other machines you read about) is the following: 1. set your p-stat to activate the element on 0.8bar (it should stop @ 0.95-1.0bar). 2. You need a way to get your GH up to brew temp at the start of a brew session, I suggest a few (3-4) back flushes. 3. flush till the boiling stops (you need fast hands as the rotary on this machine will get you from boiling to cold water too quickly). 4. Lock in your (already prepared PF) and brew.

This should get you started on reasonable grounds till you get a feel for this thing and come up with your own techniques/mods/prayers .

Congratulations on your new toy, welcome to the club, and all the best shots .

gyro wrote:You will want to descale the machine I would imagine. I'm sure you'll find heaps of info on that if you search for it on this site.

I have had a technician have a look at a boiler, and he said it was pretty clean. But thank you for the suggestion, I will think about it later on.

gyro wrote:Regarding the milk, it will most likely be lack of experience. Again, a good search on this site should yield results. For large boilers, depending on steam tip, I have found that centering the tip in the middle of the jug a centimeter or so below the surface is a good place to start.

I have a three-hole steam wand. Will try to post a picture later. As for the technique, that is exactly how I do it. I also have a pitcher in the freezer, and milk is ice-cold—to gain more time for frothing.

gyro wrote:Read up on dosing, distribution and tamping. And MAKE SURE YOU HAVE FRESH BEANS. Good luck.

I have been practicing dosing, distribution and tamping a lot. Read almost everything about it. The pity is that a new basket and tamper will arrive some time next week, so I am stuck with a ridged basket and a flat-bottomed glass as a tamper (yes, I am paying attention not to break it). Understanding that I do not have the ideal instruments nor coffee for tinkering with espresso extraction (now it is dark, runny, almost without crema, bitter)—I am focusing more on getting to know the insides of the machine, and on frothing the milk. And thank you for the wishes.

Lowering the boiler pressure.
I have turned the Parker thermostat (? I am still unsure what is what) clockwise one full turn, and got the pressure in the boiler from 1,3 to 1,1 bar. I think it could be enough tinkering with the boiler pressure for starters.

Promac is Rancilio's "second brand". What you've got is an S26 in a cheaper skin, the internals are all Rancilio and parts supply is easy.

Alan

coffee.me wrote:With the above assumption, your machine holds ~100ml in the HX. I can't tell from your photos if you have a thermosyphone or not but I'd guess not based on what's visible from the photos. Your machine might(or not) have a flow reducer in the GH. Do one thing, measure how much water you get in 10secs (with no PF in the group) to verify. If you have one (a jet) your life should be much easier.

First of all, thank you for the wealth of information, now I will have something to process I did the measurements you suggested, and they are as follows:
1st run after machine sits for 15 minuts: 80 ml
2nd run 2 minutes after the first one: 80 ml
What does it say?

coffee.me wrote:I'm guessing your steam tip has 3 or 4 holes. For easy steaming for smaller amounts of milk, you need to reduce this number to 2 holes. You either close the extra ones on your current tip or buy one with 2 holes.

The steam wand has 3 holes. 1 hole too many that it is, for smaller quantities. I think I should somehow, upon your suggestion, close (non-permanently) one of the orifices. Any ideas? (EDIT: a toothpick?)

coffee.me wrote:1. set your p-stat to activate the element on 0.8bar (it should stop @ 0.95-1.0bar).
2. You need a way to get your GH up to brew temp at the start of a brew session, I suggest a few (3-4) back flushes.
3. flush till the boiling stops (you need fast hands as the rotary on this machine will get you from boiling to cold water too quickly).
4. Lock in your (already prepared PF) and brew.

1. I am afraid I do not know where is a p-stat (pressure stat?) and how I can adjust it with such a precision. And what element should be activated, heating? After the handle on the manometer shows 0,8 bar? Now it goes to 1,1 bar and stops there. Is that by turning that Parker knob I posted before?
2. no problems with understanding that
3. boilng stops? how do I know it has stopped? what would give it away, the sound in the boiler?
4. understood.

coffee.me, thank you for such valuable information, it will cut my learning time considerably.

Alan Frew, I am happy you too confirmed it. I was not sure what machine (insides) did I get and where to find info on that—google did not show much at all. Now I will look into Rancilio S26, and apply the tweaks and knowledge-base on my machine.

Three-hole steam-wand tip, macro photo. The inner diameter of the tip is 1 cm.



And also I attach a photo of the machines' insides. Thanks to coffee.me for identifying the parts.

Yup, on your photo, 1 is the p-stat, 2 may be the brain box, 3 is your boiler fill solenoid.

80ml says you don't have a small water jet, sorry ; not very sad though as it is still workable. For the steam tip, I got several 4-hole tips and permanently closed some with epoxy; I'm not sure if that's the best thing to do but it works very well for me and now I have 1, 2, 3 and 4-hole tips ... but I like to tinker.

Vad wrote:1. I am afraid I do not know where is a p-stat (pressure stat?) and how I can adjust it ..........by turning that Parker knob I posted before?

Yes, p-stat= pressure stat, just set it to reach a maximum of 1.0bar for now but make sure you warm up your grouphead before brewing a shot as explained ... 1.0bar is just a quick, good, starting point, since you're just starting.

Vad wrote:3. boilng stops? how do I know it has stopped? what would give it away, the sound in the boiler?

By this I meant the usual HX flush talked about in many places, the idea here is to flush the extra heated water from your HX. So, you push the brew button, you get the boiling water (or steam from grouphead) out, then stop.

Oh, I just noticed you have the plastic thingie on your boiler safety valve, I think that must be removed for it to work, hopefully someone else can confirm this.

Thank you, it is much clearer now. I have updated the insides photo now.

Vacuum breaker: When machine is warming up, that small thing in the middle of the bolt begins to rotate and unscrews itself with pft-pft sound and drops of water flowing from there. Then after 5 seconds it lets out a "plop" and stands in position. (just an info on how it behaves)

As for the frothing, I tried covering one hole with a toothpick. Longer warming times (good), but almost no foam and increase in volume. Covering two holes even deepened the things observed in the previous case.

I will further decrease the pressure in the boiler as you suggest, to 1 bar. I also think, after reading the forums, that maybe a PID'ing and thermocouple'ing the machine would be a good thing to do, if my goal is a repetitive result and more steep learning curve. I guess I will have to write an email to erics.

Update on reducing the boiler pressure:
I have turned the thermostat knob yet one more turn clockwise. And now the pressure handle slowly goes to one bar, then machine clicks (heater activates?) and in 5 seconds it goes to 1.2 Bars. Then there it hold for 10 seconds and starts slowly creep back to 1 bar. There the cycle repeats. It is like that for 40 minutes now.

Question 1: do I have to adjust something else, to get 1 bar pressure without jumpy handle and pressure running from 1 to 1.2 bars?

Question 2: is the water level in the boiler a constant, or it can be tweaked to my benefit? On Linea I know that one can pull up the level probe and see the level of water in the window. How to adjust (and to know what the level is?) on this machine?
Thank you.

p.s.: Also, there is 2x more water coming out of the steam wand when opened (as compared to the times when I had 1.3 bar) and before the steam is dry.

Vad wrote:Thank you, it is much clearer now. I have updated the insides photo now.

A few more corrections to your photo:
- 7&9, the thick blue and brown wires are for the heating element, not anything else.
- level probe is the thin pinkish wire @ 11:30.
- safety thermostat is the non-plastic wire @ 12:30.

Vad wrote:And now the pressure handle slowly goes to one bar, then machine clicks (heater activates?) and in 5 seconds it goes to 1.2 Bars. Then there it hold for 10 seconds and starts slowly creep back to 1 bar.

So now you have your boiler pressure @ 1-1.2, my original suggestion was to have it @ 0.8-1.0.

Vad wrote:I also think, after reading the forums, that maybe a PID'ing and thermocouple'ing the machine would be a good thing to do, if my goal is a repetitive result and more steep learning curve. I guess I will have to write an email to erics.

Yes & no! A strong yes for erics' but take it easy on the PID talk . PIDing a HX is a whole other topic and at this stage of your relationship with the machine, I'd recommend you get to know each other better first . As for erics', that would be one of the best things you'd mod your machine with, even this early on.

Vad wrote:Question 2: is the water level in the boiler a constant, or it can be tweaked to my benefit? On Linea I know that one can pull up the level probe and see the level of water in the window. How to adjust (and to know what the level is?) on this machine?

No sight glass on this one, but you can move the level probe up to increase water level.

Final advice: take it easy, drink some coffee, learn and enjoy the incremental improvements .

Thank you for the corrections, I have now updated the picture. As for the PID, I will lay off, as you say, until I learn more about heat-exchange group, temperature behaviour of my machine. I am in talks with erics about thermocoupling, however

coffee.me wrote:So now you have your boiler pressure @ 1-1.2, my original suggestion was to have it @ 0.8-1.0.

So I will have to turn the knob even more. The thing is, that when the machine arrived, when it was at 1.3 bar—there was no such behaviour (going back and forth 0.2 bars in quite a short time). That was what puzzled me. So it is normal that it "surfs" the pressure in the boiler every 2-3 minutes? Click... click... click. Tomorow I will try to lower it down to 0.8-0.9 bar in a way that it rises to 1 bar at the peak. I guess water level in the boiler has nothing to do with it?

It's a pity I do not know the level of water in the boiler, no the lenght of the probe, so that I can put it in the boiler in such a way that the water fills just a little over the half of the boiler (I believe then a good dry steam is created). Now the probe seems to be all the way in, and I guess I just have to purge the wet steam for two seconds before steaming—no problem.

I will buy a fresh coffee, tamper and straight wall double basket on monday/tuesday—then I could taste and enjoy coffee Now it is just black runny substance, slightly burnt and almost no crema.

Thank you again for the tips.

Vad wrote:It's a pity I do not know the level of water in the boiler, no the lenght of the probe, so that I can put it in the boiler in such a way that the water fills just a little over the half of the boiler (I believe then a good dry steam is created). Now the probe seems to be all the way in, and I guess I just have to purge the wet steam for two seconds before steaming—no problem.

Don't stress about it, its largely condensation in the system I believe. I have a fairly good machine and I need to purge a second or so of water out of the wand before getting nice dry steam.

I would really recommend getting some fresh beans, it makes a world of difference. Even without a proper tamper, this will change everything. A good tamper is needed, but you will see a tenfold difference from the beans more than the tamper.

There are many variables in this. Regardless of what you do for some time, you will be inconsistent and therefore get variable results. This is largely because you won't have acquired the 'eye' for it yet. You will think you are doing the same each time, but I can almost assure you that you will not be.

I wanna open a cafe too!

Cheers, Chris

Vad wrote:As for the frothing, I tried covering one hole with a toothpick. Longer warming times (good), but almost no foam and increase in volume. Covering two holes even deepened the things observed in the previous case.

Vad wrote:The steam wand has 3 holes. 1 hole too many that it is, for smaller quantities. I think I should somehow, upon your suggestion, close (non-permanently) one of the orifices. Any ideas? (EDIT: a toothpick?)

I've never been a fan of this, and given your stated objective, you need to learn to use it how it is. I have a four hole tip and can microfoam 100mls no problems, just took a while to learn - a necessary evil. For a small amount like that, I use a smaller jug (maybe 250mls) but need to only partially open the steam valve. For 250mls, I use a 600ml jug with the steam at full bore. Practice and don't expect miracles straight away - if it was so easy, there wouldn't be so many mediocre coffees out there.

Oh, and if you haven't already, find some YouTube videos on steaming milk.

I use the same boiler and head as you do on my S27. I have one of GregS's thermoprobes set in the head of mine. Using a fast flush and then loading the shot method works best with this head for me as I am using it comming from idle a lot and need to pre-load the head with heat.

I set my pressure stat to top out or click off at about 1.1 bar on the boiler gauge.

Once you have that pressure the head will need a pre-flush to get it up to temp. When you flush the HX at 1.1 bar you will get a small flash steam 'dance' from the head. Once that is gone use about another 1 second of unrestricted flush for heating.

Have your shot in the pf ready in advance, and once that flush is done lock in your shot and start the pull. If you do that all somewhat in that order I have a stable temp on my reading above the head. You will have to gauge the thermal loss yourself, but I am able to vary it from cold, to tasty, to hot in about a 20 second window after the heating flush.

Remember this head will never overheat, but the HX will. Use one to defeat the other, if you are pulling only a shot once in a while. This design is made to pull shot after shot and let the boiler pressure set the working rate shot temp.

-Cecil

I have today set up the boiler pressure to 0.8-1 bar. As many of you suggested yesterday. Quite a step-down from 1.3 bar as it was before I think it might also improve my steaming, since it won't happen this fast and I will have the time to do it properly.

CRCasey wrote:When you flush the HX at 1.1 bar you will get a small flash steam 'dance' from the head. Once that is gone use about another 1 second of unrestricted flush for heating.

For how long do you see that steam dance? I see it for about 3 seconds, is that the "dance"?

CRCasey wrote:This design is made to pull shot after shot and let the boiler pressure set the working rate shot temp.

Let boiler pressure set the working rate? When the shot should be pulled, I have to wait until the pressure in the boiler at its peak (hear a click and a handle on the manometer stop), then flush as you said (the pressure goes to about 0.95 bar), and then pull a shot. I think it will go to 0.8 during the shot pulling, and then will go back up to 1 bar. So this is the ideal arrangement for this type of boiler?

gyro wrote:I would really recommend getting some fresh beans, it makes a world of difference. (...) I wanna open a cafe too!

Yes, the beans will be on monday/tuesday. That is also why I do not obsess about bad espressos I am getting from it now. I told to myself that untill now I would try to learn (at least a little) steaming technique, temperature surfing, and generally get to know the machine, what are other people's recommendations are etc.
Thank you for the encouragement regarding steaming. I was beginning to think it is impossible to do on my machine with three-hole tip. So now I will just train, train, train. UPDATE: Wow, now I am getting somewhere. 0.95 bar boiler pressure. The foamiest milk so far. Texture as a paint. Still not much of a foam, but at least I have a little more time to react.
Coming from a graphics designer and photographer background, I take the coffee shop as an interesting and exciting road, totally different world.

Vad wrote:For how long do you see that steam dance? I see it for about 3 seconds, is that the "dance"?

The flash boil at 1.1 bar boiler pressure lasts about one second.

Vad wrote:Let boiler pressure set the working rate? When the shot should be pulled, I have to wait until the pressure in the boiler at its peak (hear a click and a handle on the manometer stop), then flush as you said (the pressure goes to about 0.95 bar), and then pull a shot. I think it will go to 0.8 during the shot pulling, and then will go back up to 1 bar. So this is the ideal arrangement for this type of boiler?

I meant that when working with the machine at a regular steady pull rate that the overall shot temp is dialed in by the pressurestat, not so much by timing. That was all.