Seb Junior Member Joined: 24 Aug 2009 Posts: 6 Location: Montreal, Qc Expertise: I love coffee
Espresso: Elektra Micro casa Grinder: Solis Maestro Vac Pot: Vintage Hellem Drip: Crappy Oyster...
Posted Wed Oct 14, 2009, 5:41am Subject: Need help with "exploding" MCal
Hello,
I previously reported this type of incident I'm having with my micro casa a leva (here). Basically, mid-shot the portafilter comes loose and all content of the brew chamber (boiling hot water and ground coffee) is projected across the kitchen. I have now lived through 4 of those events, and during the last one (this morning) I was able to clearly see the handle of the portafilter turn and unlock itself.
I have descaled the machine recently and after incident #3 (this weekend) I just completely cleaned the screen below the piston, the piston itself and the group. After inspecting the seal that hold the screen in place (and seals the portafilter), I lean toward replacing it. It doesn't look damaged at all and doesn't leak, but it feels pretty "hard", almost like plastic. Since I don't have a new seal at hand to compare the feel, it is difficult to assess how much it has hardened over time...
Anyone ever experienced that? How did you resolved the situation? Any other idea regarding actions to take?
Zin1953 Senior Member Joined: 9 Dec 2005 Posts: 1,695 Location: Berkeley, CA Expertise: I live coffee
Espresso: Elektra T1 - La Valentina -... Grinder: Mahlkönig K30 Vario -... Vac Pot: no, Press Pot Drip: Chemex Roaster: No, no, not another...
Posted Wed Oct 14, 2009, 6:35am Subject: Re: Need help with "exploding" MCal
I can't speak to the MCal, but I had the same thing happen to me once or twice on other machines . . .
With hindsight, as near as I can tell, it happened when I would updose too much -- the puck would be tight against the dispersion screen so there was no room for expansion. Thus, as the puck did expand, it cannot expand up into the (non-existent) headspace, so it pushes down and forces the portafilter out of the grouphead . . .
stefano65 Senior Member Joined: 30 Oct 2004 Posts: 825 Location: Eugene OR Expertise: Professional
Espresso: Vibiemme,Elektra, Grinder: Macap,Cunill, Isomac Vac Pot: not Drip: not Roaster: not
Posted Wed Oct 14, 2009, 12:34pm Subject: Re: Need help with "exploding" MCal
First before looking at the machine make sure that your grind is not too fine in addition the the suggestion above, then then machine: grouphead gasket basket completely inside the portafilter then check that the wings of the portafilter are not too worn out same could happened to the grouphead it self
Seb Junior Member Joined: 24 Aug 2009 Posts: 6 Location: Montreal, Qc Expertise: I love coffee
Espresso: Elektra Micro casa Grinder: Solis Maestro Vac Pot: Vintage Hellem Drip: Crappy Oyster...
Posted Thu Oct 15, 2009, 8:59am Subject: Re: Need help with "exploding" MCal
Thanks for following up.
I have found no correlation between the dose and the explosion events, same with the grind. On the last event, the pour was going well and the portafilter popped-off rather early in the extraction (1/3 of the lever course maybe, i do mostly single pulls). I thought that the fact that the pour was coming at a decent rate (I aim for around one ounce per 30 sec.) suggested that nothing was clogged.
I will carefully inspect the portafilter wings and the notches in the grouphead tonight. I haven't noticed anything during my recent exhaustive cleanup. If there is an issue on the portafilter, I guess that my only solution would be to buy a new one? Same thing with the head?
I just ordered a new gasket seal from orphanespresso.
Another observation I've made concerns the state of the dispersion screen just below the piston. I would estimate that about half the holes are completely blocked. Cleaning it with a brush doesn't do much, using a needle is the only way I've found to work (painfully slow!). Any chance that pressure buildup _above_ the screen is the cause of my troubles? Is it a good idea to change that filter from time to time? Is there a more efficient way to clean it?
Another observation I've made concerns the state of the dispersion screen just below the piston. I would estimate that about half the holes are completely blocked. Cleaning it with a brush doesn't do much, using a needle is the only way I've found to work (painfully slow!). Any chance that pressure buildup _above_ the screen is the cause of my troubles?
It certainly sounds to me like you are dosing too much -- the coffee should not be getting through the dispersion screen that much! Now that it is that blocked, the only way to clean it -- as you've discovered -- is with a needle.
How often to you clean the grouphead, shower screen, and dispersion block? I grant you, I have a Elektra T1 (not an MCaL), but I clean them weekly.
Stefano -- who sells and services Elektra machines -- is a great source of information (and service)!
Warrior372 Senior Member Joined: 2 Jan 2007 Posts: 178 Location: Chicago Expertise: I live coffee
Espresso: Olympia Cremina Grinder: La Cimbali Junior Drip: Trechnivorm Thermoking &... Roaster: Hottop Roaster & Zack &...
Posted Fri Oct 16, 2009, 2:38pm Subject: Re: Need help with "exploding" MCal
Sebastien,
I use to have an MCaL and that happened to me twice. . . I know how you feel as it makes a HUGE mess! I even shattered a few shot glasses with the momentum from the portafilter shooting down with so much force. In my experience the easiest way to 'clean' the group screen on an MCaL is with an empty portafilter linked into the grouphead, pull the lever down about halfway and shake the portafilter side-to-side. Follow that by rubbing the group screen with a cloth.
As far as preventing the portafilter from blowing off the machine like a cannon, I began to do three things. First, I became super paranoid because when that happens espresso flies absolutely everywhere. The next two stemmed from my paranoia. I would lock the portafilter into place as tightly as I could, and then I would hold the base of the machine and actually hit the portafilter relatively hard to the right with the side of my hand. As mentioned, after this happening twice I became so paranoid I never left the machines side again, so while I was waiting for the spring mechanism to finish pulling the shot, I would stand on guard with my thumb looped around the portafilter. Through utilizing this maneuver I actually caught / prevented the portafilter from sliding far enough to the left to shoot off.
The I could ever come to was that my grind and dose of coffee had to have been off; but even with what I perceived to be the perfect grind / dose on that machine, the portafilter would slide every now and again. Hit it to the right, it should not happen as often!
Best of luck. Again, I know how annoying / messy this issue can be!
CMI Senior Member Joined: 22 Nov 2005 Posts: 3 Location: home Expertise: Just starting
Posted Mon Oct 26, 2009, 3:33am Subject: Re: Need help with "exploding" MCal
This happens to me often...I find that when I keep the head clean (washing out after every shot) this does not often happen.
I have another problem, however.
My machine has started leaking like crazy and doing other annoying things. First, it does not heat up properly until after I let out some steam. That is usually accompanied by leaking out of the pressure escape valve at the top. Second, omnce properly heated the first few shots are accompanied by the release of large amounts of hot water from the small hole at the back and top of the group head.
Seb Junior Member Joined: 24 Aug 2009 Posts: 6 Location: Montreal, Qc Expertise: I love coffee
Espresso: Elektra Micro casa Grinder: Solis Maestro Vac Pot: Vintage Hellem Drip: Crappy Oyster...
Posted Mon Oct 26, 2009, 2:09pm Subject: Re: Need help with "exploding" MCal
Hello CMI,
If the pressure escape valve you're referring to is the kind of hexagonal nut behind the boiler cap on the top, then I've also seen the kind of situation your seeing. I've solved it by adding a drop of olive oil (any other recommendation?) just on the mobile pin in the center of the hex nut. Then, using a sharp knife you can pull this pin up by lifting the C-thing that hold that pin in place. My understanding is that the problem happens when this valve refuse to shut off (allowing to keep the pressure inside) under little pressure.
regarding your issue with leaks from the small hole back of the piston chamber, I've had the exact same issue. It is characteristic of a piston seal that leaks. Upon recommendation of other members of this forum, I've done a serious descale of the machine. To my surprise the piston seal recovered completely and I haven't seen leaks from that same spot since then!
I would believe that your two issues will not come back if you descale regularly (every 4-6 month depending on your use).
As for my own issue, I've just received my group head seal today from OrphanEspresso. I'll come back to this thread with a complete report later on. :)
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