stefand Senior Member Joined: 26 Jan 2004 Posts: 17 Location: stockholm, sweden Expertise: I love coffee
Espresso: Isomac Tea Grinder: Mazzer Mini E, Isomac... Roaster: Hearthware Precision Roaster
Posted Mon Jan 26, 2004, 4:29pm Subject: TEA problem: Metal flakes in espresso: E-61 dissected - pics
Hi!
First of all I must say that I am impressed with this website an all accumulated knowledge that is exchanged between all you devoted espresso lovers.
I hope to get some of this knowledge to hopefully solve this major problem that has strucked my loving TEA. I owned my TEA for two years and it has given me great pleasure without any problem.
The story is: During this time I have made one preventiv descaling (I use bottled water) and daily backflushes with water. I pull about two shots a day. I have not been able to get some machine cleaner until now so now I was ready to both backflush with cleaner (Clean Express, from Italy) and to do my annual preventiv descaling.
I heated my TEA for 30 min and began to backflush with cleaner:
*Half tea spoon of cleaner in blind filter. *Start pump and run for 10 sec. *Stop pump and backflush a couple of times with water.
I repeated this 5 times but the water coming out of selenoid was still brownish. I then decided to do some more backflushes but entirely shut off the machine while the pump was running to keep the pressure up for a longer time with cleaner (2 minutes). When the machine was shut off the pressure gauge showed 8 bar and after 2 min I released the pressure trough the selenoid with the lever. This I repeated 5 times and the water coming out was now totaly clean (no metal flakes). After that I flushed and backflushed the grouphead thoroughly with water.
Now it was time for the preventiv descaling of the HX and grouphead. I filled the water tank with citrus acid solution (1.5 table spoons/liter) and flushed and backflushed the grouphead (about 2 liters). It was now that I started to see tiny metal flakes in the water that flushed through the shower screen. After this horrible discovery I have flushed many liters of water through the HX and grouphead but the metal flakes are still coming out. The flakes are very shainy almost like crome. I have removed the shower screen and checked it. The flakes does not come from the screen. The metal in grouphead above the shower screen looks okei and the same goes for the dispersion bolt. No sign of metal wearing of.
I belive the following may have happened:
*Shutting of the machine (2 min) with pressure (8 bar)applied in grouphead with cleaner made some seal to brake or affected the metal in some way.
*Maybe cleaner has passed on to HX or was left in small quantities in the grouphead and has reacted in a nasty way with the citrus acid solution. This reaction causing some metal surface to wear of.
My questions are: Inside the HX, what is the the surface made of, could it wear of? Is it possible to change only the HX or must I replace the hole boiler if neccesary? The best way to dissasambly the E-61 grouphead to see if something inside has weared of? What is the surface in the grouphead made of, brass?
As you can understand I am facing a delicate problem. I would appreciate all replies and information that could help me out on this one. I have excluded the possibility to glue a magnet to the bottom of my espresso cups :)
hamm Senior Member Joined: 22 May 2003 Posts: 530 Location: Kettering, Ohio Expertise: I live coffee
Espresso: Alex Duetto (1st gen) Grinder: Mazzer Mini Vac Pot: I'm not that kind of guy... Drip: From the faucet occasionally Roaster: I buy from several
Posted Mon Jan 26, 2004, 8:12pm Subject: Re: TEA problem: Metal flakes in espresso
steffet Said:
Hi!
The story is: During this time I have made one preventiv descaling (I use bottled water) and daily backflushes with water. I pull about two shots a day. I have not been able to get some machine cleaner until now so now I was ready to both backflush with cleaner (Clean Express, from Italy) and to do my annual preventiv descaling.
Stefan,
How often to you backflush with the cleaner? The instructions on my Tea came from Chris' Coffee Service and they say to only use the cleaner once a month. I do not know why, but every time I use the cleaner, I notice the lever seems to stiffen, as if sand or dirt were inside it. I wonder if the cleaner is abrasive enough to cause the metal flakes to come off?
Now it was time for the preventiv descaling of the HX and grouphead. I filled the water tank with citrus acid solution (1.5 table spoons/liter) and flushed and backflushed the grouphead (about 2 liters). It was now that I started to see tiny metal flakes in the water that flushed through the shower screen. After this horrible discovery I have flushed many liters of water through the HX and grouphead but the metal flakes are still coming out. The flakes are very shainy almost like crome. I have removed the shower screen and checked it. The flakes does not come from the screen. The metal in grouphead above the shower screen looks okei and the same goes for the dispersion bolt. No sign of metal wearing of.
It sounds like some chrome plating is flaking off of something. That does not seem logical because I do not think the chrome plating is on the insides. I guess it may be possible that the metal flakes might be coming from a hose, or a fitting that may be ready to be replaced. Perhaps the pump?
You also said you use bottled water, but how certain are you that the water is free of harmful minerals? That could be an issue.
I also read that you have owned your Tea for two years. If your water is treated or filtered which I assume it is, I do not know if you would actually need to descale the insides. I mean, if you are averaging two shots per day, not as much water is flowing through as say a machine that is making 20 shots per day. I will go back and re-read the instructions I got from Chris' Coffee and if I learn anything, I will pass it along.
I am sorry I am not able to offer any better ideas, but maybe someone else can shed some light on it. I would like to hear as well in case I ever have this problem. I know that the cleaner sure makes the lever feel awful to use!
Good luck, I hope you solve it. A Tea is too good a machine to die after two years.
jim_schulman Senior Member Joined: 19 Dec 2001 Posts: 3,772 Location: Chicago Expertise: I live coffee
Posted Mon Jan 26, 2004, 9:02pm Subject: Re: TEA problem: Metal flakes in espresso
I'm not sure what the source of your metal bits is. As far as I know, the water path is all brass/copper. The boiler outside is nickel plated, but the interior is marine brass.
There are steel springs and valves inside the head, and a metal valve seat may have shredded over time.
Since the bits are making it through the shower screen, they must be relatively small, so it could also be scale.
I would remove the group gasket and shower screen and run some water and see what gives. Then, remove the littel screw at the front of the group, and (carefully) run a little water (try not to turn the pump on, just lift the lever to the drain height) catching it in a rag, and see if there's stuff there. If there isn't, it's something in the lower group, probably the dispersion screw. If it's still there, you'll need to disassemble the head, and that goes beyond my knowledge.
Posted Mon Jan 26, 2004, 10:13pm Subject: Re: TEA problem: Metal flakes in espresso
Stefan,
I didn't have time to read every post, and have to get off to bed, but I just wanted to make sure this prospect had been mentioned--is your grinder set so close that the burrs may be touching during grinding? The metal could be miniscule shavings off your grinder's burrs. Depending upon your grind fineness setting, and the possibility that your upper burr & lower burr are not perfectly level (I don't know much about the Isomac grinders), you may have some touching during grinding going on. If the upper burr is slightly loose--even the least bit--they may not touch when the grinder has no beans in it, but the instant a bean touches the top burr and throws it off level, they could touch long enough to spew a few fine metal shavings into the mix.
Also, have you tried calling the vendor (if purchased new)? They are often very helpful, and usually don't like dissatisfied customers. I hope you solve your problem!
stefand Senior Member Joined: 26 Jan 2004 Posts: 17 Location: stockholm, sweden Expertise: I love coffee
Espresso: Isomac Tea Grinder: Mazzer Mini E, Isomac... Roaster: Hearthware Precision Roaster
Posted Wed Jan 28, 2004, 3:20pm Subject: Re: TEA problem: Metal flakes in espresso
Thanks, Michael, James and Anthony for your input on my questions about metal flakes coming out of my TEA.
After reading your posts and talking to an espresso repair shop I will do the following this weekend:
*I will first of all check all hoses and fittings. *The next step will be to get inside the HX (note, not me personally:) to see if the flakes comes from the HX walls. *The third step will be to dissasamble the e-61 grouphead starting with the lever part and then if necessary the upper part. *The pump could be an issue.
Hopefully I will find the origin of the metal flakes during this intrusion in my TEA. I will keep you posted of my progress. I have a hunch that what happened was that the cleaner made its way to the HX and the small quantities left in there reacted with the citrus acid solution when I made the preventive descaling.
Here is some answers to your questions:
This was my first backflushing session with cleaner in two years. The flakes comes straight out the grouphead without passing any coffee. So it could not be a malfunction in the grinder.
I will have a thrilling weekend no doubt of that...
stefand Senior Member Joined: 26 Jan 2004 Posts: 17 Location: stockholm, sweden Expertise: I love coffee
Espresso: Isomac Tea Grinder: Mazzer Mini E, Isomac... Roaster: Hearthware Precision Roaster
Posted Thu Feb 5, 2004, 4:08pm Subject: Re: TEA problem: Metal flakes in espresso: E-61 now dissected
I have found the origin of the metal flakes that came out of the grouphead of my TEA. The E-61 grouphead is the guilty part. Obvisouly there are parts that are chrome plated inside the E-61. I think the following happened: My extensive cleaning lead to that some cleaner remained in the grouphead and reacted with the citrus acid I used for the preventive descaling right afterwards. This reaction caused the chrome to start to dissolve.
Possible solution for this problem: I think I could sand blast the erroded parts to get rid of all the chrome surfaces in my grouphead. The parts seems to be made off solid brass. Why have chrome surfaces on these parts? It is bound to come off over time. Are we all E-61 users enjoying our espresso whith a twinkle of chrome!?? I do not hope so.
I have enclosed some pics which I took during my dissection of the E-61 grouphead.
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