LatteLiker Senior Member Joined: 15 Dec 2008 Posts: 24 Location: Bay Area Expertise: I love coffee
Posted Wed Jan 25, 2012, 1:04pm Subject: Water Does Not Flow Easily into Grouphead -- Europicolla
1 I have confirmed by visual inspection with the unit disassembled and the piston removed from the cylinder, that the piston rod is firmly screwed onto the piston.
2 I have previously had good success getting good water flow into the group head by blowing out the valve hole in the cylinder wall with the group head taken off the boiler body and the piston removed from the cylinder. That seems to clear out some kind of blockage. I assume that I should not have to do this very often, given the required disassembly.
3 Sometimes I can get good flow of water by rapidly pulling up on the lever for the last ~20% of the travel, after first having slowly pulled the lever up for the first ~80% of its travel. Again, this seems to clear out some kind of blockage in the valve hole in the cylinder wall.
4 I always use the trick that I have seen on this forum of disengaging the portafilter basket handle for part of its rotation, so as to avoid as much as possible pulling a vacuum when I lift the lever. I then rotate the portafilter handle firmly into closed position before attempting to lower the lever.
5 Even with the portafilter basket handle partially disengaged, I notice often that the water level seen through the sight glass often raises one-for-one with my raising of the lever.
6 I suspect that I have let scale debris get into the group head, and that that scale debris from time to time migrates to cover the valve hole in the cylinder wall - and that I have varying degrees of success in dislodging this scale debris using the above tricks.
HELP! Does the above sound familiar to any of you? I suspect that my root problem is not descaling often enough. I use Dezcal descaler (citric acid, aluminum salts, sulfamic acid powder) from Bed Bath and Beyond. I descale about every 1000 cups.
Posted Sat Jan 28, 2012, 10:11pm Subject: Re: Water Does Not Flow Easily into Grouphead -- Europicolla
Hi...I would like to confirm from your other thread: have you taken the group apart completely? If not, you should remove the entire group from the boiler, remove the piston, remove the siphon tube, and check to see if you can actually find the blockage/depris.
You might want to check the position of the restrictor nut+cap at the top the of piston. If they are too low (or if you lever in on upside-down) you will get less flow at the top of the lever throw. I know this is not how they are supposed to work, the top of the interior of the piston chamber is supposed to be what limits the top of the throw, but I have seen plenty of nut+caps with substantial wear from lever contact, so it's possible.
You should also check the pressure/temp. Insufficient temp = low pressure = low flow into the group.
Also, I'm assuming that you are using a pre-millenium machine, correct?
LatteLiker Senior Member Joined: 15 Dec 2008 Posts: 24 Location: Bay Area Expertise: I love coffee
Posted Sat Jan 28, 2012, 11:20pm Subject: Re: Water Does Not Flow Easily into Grouphead -- Europicolla
Russel, thanks for your suggestions:
1 I had the group head apart several weeks ago. I removed the piston, and with a bent coat hanger, pushed through the valve hole in the cylinder wall and then washed it out. I did not sense that I was clearing a blockage, but, when I reassembled the unit, it worked fine for several weeks.
2 I do not have the restrictor nut and cap on the unit. I stop my pulls when I sense that the piston is coming into contact with the screen.
3 The lever is not upside down according to the drawings which show the forward hole pair lower than the rearward pair. It seems intuitive to me that the rise would be better with the forward pair of hole higher than the rearward pair, but I have not tried that yet.
4 I don't know about millennium. I bought the machine in 2007 from William-Sonoma, and the shipping slip specifies the product as "EPC-8."
5 I have wondered about boiler pressure. I go by the extinguishment of the green light. However, I have experimented a little with waiting longer periods of time to start my pull after the green light goes out, without success. For example, I am trying steaming the milk before rather than after the pull. Is there a simple way to confirm the relevant boiler temperature? The steam force certainly seems as strong as ever at the steam wand.
6 I descaled several times with Dezcal yesterday, which gave some temporary success, but that did not last long.
7 I'm about ready to disassemble again, re-pierce the valve hole, and experiment with verious soaks and blowing out with air, etc.
8 If I have to, I'll resort to removing the sleeve again, to see what is in there. On this sleeve topic, I wonder if it is possible to screw that sleeve in too far, which would lessen clearance to the piston when the piston is at the top of its travel. However, the last time that I put the sleeve back in, I did not have much choice but to screw it back in all the way, so as to have sufficient clearance to lock the portafilter lever in place.
Any further thoughts that you may have, I appreciate.
Posted Mon Jan 30, 2012, 12:11pm Subject: Re: Water Does Not Flow Easily into Grouphead -- Europicolla
Hi.
If you purchased it new from William Sonoma in '07 you have should a "Millenium" Europiccola. You can look on the label on the bottom, but if you have a teflon cuff in the group then you know it is a Millenium. If you have only an on/off switch then you have on with a pressurestat instead of a thermostate (a good thing). The forward hole should be lower than the back one.
Some thoughts
You haven't mentioned the syphon tube...is it there, is it in good shape, does it thread cleanly into the little plastic bit in the back side of group?
You might try bleeding some air from the steam wand after the green light goes off. My '10 Europiccola exhibits a very large amount of false pressure in the steam arm that has to be bled out for the machine to reach full pressure.
You may want to check the orientation of the piston head seals. They are V shaped in profile, and the "vally" should be oriented away from the center of the piston head, the bottom one towards the dispersion screen and top one towards the lever ( like this: |> <|-------- ). The "vally" should be free of lubricant.
I agree that you could try removing the teflon cuff from the group to see if there is debris floating around in there and periodically blocking the water flow...although I think there would have to be a lot of debris to do so. It should be fine screwed in all the way.
Posted Wed Feb 1, 2012, 6:29pm Subject: Re: Water Does Not Flow Easily into Grouphead -- Europicolla
Agree with everything Russ said above.
You asked if there is a simple way to check pressure/temp. You can buy a pressure gauge for about 25 bucks from Orphan Espresso that slips over the end of your steam wand. That could help rule out the pressurestat as the culprit. You expect to see the green light go off when it's at .8 or .9 bar, and come back on when it drops to .6 0r .7 bar. You might even consider putting on a permanent gauge, some people do that with their Europiccolas.
It's odd to me that it seems to work well after you clean out the group innards then goes back to being a problem. Your suspicion that debris is getting loose and blocking the inlet hole seems very logical, but I've never heard of that happening. What you do hear about often, especially with machines that have the Ryton (plastic) piston is that the piston comes unscrewed a little, and that causes the group to not fill. Any chance you've been re-tightening the piston on the shaft each time you take it apart? (edit: Way up in the initial post he made it clear this was not the problem. )
Do be sure you have bled off the "false pressure" before doing a pull. When you first heat it up the expanding air in the boiler causes the pressurestat to turn it off before it's up to proper temperature. Bleeding off 10 seconds or so of steam takes care of that.
Also, before pulling your first shot, pull an oz or so through an empty portafilter to help heat up the group and to replace air in the group with water vapor. This will help you to get a less squishy pull. My routine is to get it up to pressure, then pull an oz or so of water into the cup, then further heat the water in the cup using the steamwand until the green light comes back on - this heats the cup, warms the group, and bleeds false pressure.
My millennium machine does not fill the group forcefully. It's way different than my pre-millennium machine, and the water delivery seems feeble compared to other millennium machines that I've seen demonstrated on YouTube. But it is consistent, when the green light has just gone off, if I lift the lever and hold it tight at the top with an empty portafilter it delivers about 35-55 ml of water in 6 seconds.
LatteLiker Senior Member Joined: 15 Dec 2008 Posts: 24 Location: Bay Area Expertise: I love coffee
Posted Sun Feb 12, 2012, 8:59pm Subject: Re: Water Does Not Flow Easily into Grouphead -- Europicolla
Russel, PC, thank you very much for your useful suggestions.
I have been ruminating on your inputs for a few days now, and been continuing to try to use the machine employing the tricks you suggest in bleeding off the "false" pressure before trying a pull. Finally, a few days ago, the machine reached its state like before I disassembled it a few weeks ago -- no water flow, even with an empty portafilter basket.
I just now disassembled the group head once again, this time taking out the cylinder "sleeve" as well. I am attaching here a .jpg of the inside of the group head with the cylinder removed.
The photo shows scale that had accumulated at the top of the group head, at the top of the "vent pipe" in the outer wall of the cylinder, that routes water from the top of the group head down to the cylinder valve hole.
I believe that this scale was responsible for the gradual slowing of water until I eventually could get no flow at all. Sometimes I could get a little flow by, as described by Clay Priley on the home barista forum, by "gorilla" lifting the lever quickly (claypriley on Sep 26, 2011). I speculate that this rapid lifting of the lever was pushing a little of the scale that was blocking the top of the vent pipe.
PC, you mentioned that it seemed odd that I said that disassembling the machine provided temporary relief. I agree. I speculate that blowing out the disassembled group head from the siphon tube attachment point was also dislodging some scale to provide temporary relief, but not sufficiently to really unblock the top of the vent pipe.
So, I'll see if this step today, removing the scale buildup in the top of the group head at the top of the cylinder vent pipe, will keep the unit fixed. My feeling is that the answer is 'yes.'
Posted Wed Feb 15, 2012, 11:35am Subject: Re: Water Does Not Flow Easily into Grouphead -- Europicolla
Congratulations - looks like you've discovered a new explanation for low flow infusion problems in Millennium Pavoni's. Is surprising that the bead of scale accumulates there, where you think the flow would be greatest. Perhaps blobs of scale come in from the boiler, get lodged there, and then adhere and serve as a seed surface for more scaling. At any rate is something to watch out for in these situations.
Posted Wed Feb 15, 2012, 11:43am Subject: Re: Water Does Not Flow Easily into Grouphead -- Europicolla
I have to agree, I was not expecting to see such a large amount of buildup right there. My guess (other than the possibility of scale buildup migrating from elsewhere) would be that a regular descaling process doesn't do much to clean out buildup in the group. It may be preferable to descale with some sort of rubber flow restricting insert in the PF and the lever in the up position so that the group interior has more time with the descaling agent.
Thanks for posting your findings...you never know when someone else will benefit from them.
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