Problem with backflushing Isomac Tea ll

[mp]

Ok ... where to begin ... I got a 8 month used Tea ll in January ... noticed that the lever to pull shots got stuck from time to time ... did a couple of backflushes a few weeks apart ... they went ok ... but didn't help the problem ... make about 12 doubles a week ... end of February/beginning of March I decided to descale the machine using citric acid ... did a very thorough flush ... sticky lever problem went away. All was well in Tea ll land.

Alas ... today I decided I am going to do a backflush ... took a 1/2 espresso spoon of Cafiza powder and went to work ... I noticed no liquid coming out of the pressure relief valve. I did about 5 or 6 pulls ... and still no pressure relief like when I did the first couple of backflushes. I attempted to remove the portafilter but it was like it was locked in there. Not knowing what to do I shut down the machine and hoped that the slow release of pressure would allow the portafilter to eventually come free.

My question is what happened? How do I fix it? What do I do to prevent this from happening again?

[BobS]

Just a guess, but you may have a broken part or spring. Besides the great internal pictures here, there
is a detailed - How to rebuild the E61 group, at - http://coffeetime.wikidot.com/e61-group-servicing

My guess is all you'll need to do is remove the lever and the lower assembly, then get the parts you need.
Beware that the generic rebuild kit that folks like Espressoparts offers may or may not work. I found
most of the gaskets correct, except the mushroom O-ring, which was too thick for my Andreja and the
springs were significantly different.

Still, it seems you may need a few more parts, but without disassembly it's an unknown at this time. The
great thing is the E61 head is pretty easy to take apart and put back together.

Bob

[mp]

Just a guess, but you may have a broken part or spring. Besides the great internal pictures here, there
is a detailed - How to rebuild the E61 group, at - http://coffeetime.wikidot.com/e61-group-servicing

My guess is all you'll need to do is remove the lever and the lower assembly, then get the parts you need.
Beware that the generic rebuild kit that folks like Espressoparts offers may or may not work. I found
most of the gaskets correct, except the mushroom O-ring, which was too thick for my Andreja and the
springs were significantly different.

Still, it seems you may need a few more parts, but without disassembly it's an unknown at this time. The
great thing is the E61 head is pretty easy to take apart and put back together.

Bob

Thanks for the reply Bob. Great link!

If not Espressoparts ... who would have a good rebuild kit?

[BobS]

You'll probably have to buy individual parts. But several of the sponsers would have parts. Stefano's has
a tea parts page at - http://espressocare.com/

Select: Parts --> Isomac --> Tea

Bob

[mp]

You'll probably have to buy individual parts. But several of the sponsers would have parts. Stefano's has a tea parts page at - http://espressocare.com/

Select: Parts --> Isomac --> Tea
Bob

So there is no other way of solving this problem other than taking apart the E61 and replacing all the seals etc?
Would the problem absolutely only be resolved by resealing all parts of the E61 group? Could some scale from the descaling have blocked the backflush passage?

Thanks

[HB]

I noticed no liquid coming out of the pressure relief valve. I did about 5 or 6 pulls ... and still no pressure relief like when I did the first couple of backflushes.

The cam should push down the evacuation valves as shown in the first image of Is there a purpose for the E61 middle brew lever position? (excerpted below):

For the benefit of those who are wondering what these valves look like, a few diagrams from Lino. Please do not copy these images.

The first image shows the E61 lever at the rest position. The two lower valves are open to allow the brew chamber and expansion chamber to drain. The uppermost valve is closed. Water from the HX circulates through the upper port on the left, passes alongside the "mushroom" to heat the grouphead; as the water cools it descends through the lower port on the left. The temperature difference creates a thermosyphon that circulates water between the boiler and grouphead.



The next image shows the E61 lever at the mid position. The two lower valves are closed and the upper valve is barely open. If this pump has line pressure, water will flow through the upper port, grouphead cap and screen, gicleur (yellow), descend towards the brew chamber (orange cam), and finally through the L-shaped channel to the brewhead. It's easy to see the purpose of the Allen screw (gray); it caps the hole drilled during manufacturing for the first leg of the channel.



The final image shows the E61 lever in the brew position. The upper valve is held open by the orange cam. The valve at the bottom of the expansion chamber is held tightly closed by a spring. The spring above it holding the second valve closed is weaker; it will open at about 4 bars of pressure. It only takes a second or two for the brew chamber containing the orange cam to pressurize. As the pressure builds, water eeks pass the valve below the orange cam, allowing the pressure to drop. This action is the novelty claim of the E61 patent since the pressure is automatically lower as the expansion chamber fills. Once the lower chamber fills, the pressure equalizes in all chambers and the valve below the cam closes.



The familiar "whoosh" that follows the lever being lowered is water evacuating the brew chamber and expansion chamber. Again at rest, the expansion chamber and brew chamber are empty. Water continues to circulate along the jacket of the uppermost chamber as the thermosyphon re-establishes itself.

I believe that a quick disassembly is in order.

[mp]

Hi Dan,

Thank you for the excellent diagram and commentary on the E61. So you also suggest that fixing this problem would require a disassembly and replacement of all seals etc. Is this a common with the E61 groups? About how often will this occur? Is there a way to prevent or lengthen the time between when this has to been done?

Should I have everything necessary to do the job from Stefano's E61 rebuild kit? The reason why I ask is that the kit from Stefano seems to have less parts than the kit shown at the coffeetime web site:

http://espressocare.com/Qstore/Qs...rouphead++Kit+E-61

http://coffeetime.wikidot.com/e61-group-servicing

The coils and back mounting plate is not in Stefano's kit ... does it matter ... should they need to be replaced while the group is apart? Also the group head gaskets seem to come in three sizes 8mm, 8.5mm, and 9mm. Wasn't the whole idea that the E61 was supposed to be using standard parts? What size does the Tea ll need?

http://espressocare.com/Qstore/Qs...NAME=Lubrifilm+113

Thanks

[HB]

So you also suggest that fixing this problem would require a disassembly and replacement of all seals etc.

No, I don't think this has anything to do with failing seals; their symptom of failure is a constant drip drip drip. Remove the lower expansion chamber to determine why the exhaust valve isn't being pushed open. Take photos as you proceed should you need a reminder of the reassembly steps.

For your reference, Eric provides a good hint to avoid scratching the chrome in Checking an E61 Espresso Machine for Scale:


Electrical tape or the equivalent on the wrench openings.

[CSME9]

8.5mm is standard group gasket size. My TEA believe came w/9mm but always barely locked in at 7 1/2 oclock, replaced the gasket to a 8.5mm and now securely locks at 6 1/2 oclock Think my original factory gasket was 9mm but again 8.5mm secures a lot better.

WS

The coils and back mounting plate is not in Stefano's kit ... does it matter ... should they need to be replaced while the group is apart? Also the group head gaskets seem to come in three sizes 8mm, 8.5mm, and 9mm. Wasn't the whole idea that the E61 was supposed to be using standard parts? What size does the Tea ll need?

[mp]

No, I don't think this has anything to do with failing seals; their symptom of failure is a constant drip drip drip. Remove the lower expansion chamber to determine why the exhaust valve isn't being pushed open. Take photos as you proceed should you need a reminder of the reassembly steps.

Hi Dan,

So please let me verify what you are saying ... I do not need to replace any seals. I just take apart the lower portion of the E61 group and this is the part that contains the lower expansion chamber? Nothing needs to be changed other than to disassemble and then reassemble the bottom portion of the E61 group and the problem should be fixed?

After pulling a shot this morning I noticed that the pucks are left wet ... would this be a cause of that also?

Thanks

[HB]

So please let me verify what you are saying ... I do not need to replace any seals. I just take apart the lower portion of the E61 group and this is the part that contains the lower expansion chamber?

Right, I don't know what the problem is, but it isn't seals. Upon disassembly, I expect the cause to be self-evident. One of the lower two valves isn't opening... the question is why not.

After pulling a shot this morning I noticed that the pucks are left wet ... would this be a cause of that also?

Yes.

[mp]

Yes.

Since I am a complete nubbie at ever doing something like this I am assuming that the bottom of the E61 group is here:



Please ignore the writing ... as it does not leak ... picture is provided for illustration purposes ... but the arrow is pointing at what I believe to be the bottom of the E61 group which I have to disassemble ... is that correct?

[HB]

the arrow is pointing at what I believe to be the bottom of the E61 group which I have to disassemble ... is that correct?

Yes. Here's yet another diagram to supplement the ones I provided earlier; the valves in question are labeled "Preinfusion Valve" and "Drain Valve" respectively:


Thanks to Eric Svendson for the annotations

I renew my recommendation to take lots of photos for reassembly, just in case. On the other hand, it sounds like you're concerned about your do-it-yourself skills. If so, I recommend that you bring it to a qualified repair technician for diagnosis.

[mp]

Thank you Dan. I now have a clear idea in my head at what has to be disassembled and reassembled and exactly what I should be inspecting once everything is apart. I'm just thinking ahead and wonder would it just have shifted slightly and a reassembly would fix or do you think a part may need to be replaced. I know you said that it would become self evident but am asking you as someone who has more knowledge and can better assess the probability of one or the other happening.

Thanks

[mp]

Ok ... fast forward to Wednesday ... I finally got a chance to disassemble ... the whole process I must admit was relatively painless. The only thing that I found that I question is the "Drain Valve Assembly" did not come out by itself ... it needed some force. Now not having any food grade type grease to use to try to assure that it won't go back in there so tight I decided to use a little bit of extra virgin olive oil.

Am I correct in thinking that this assembly should have fell out once I unscrewed the bottom of the assembly?

I assembled it back together and amazed myself at how quickly I was able to do it. Any tips on preventing this in the future if possible would be much appreciated.

Thanks

[stefano65]

The kit that I made is for normal wear and tear parts
the springs,shafts,seat are not necessary to replace UNLESS they look worn out
my guess is that your grouphead not only is completely gunk out with coffee but the 2 square spindles are not square anymore and they developed and edge
of course mine is just a guess

[mhoy]

Post some pictures of what's inside for better advice.

BTW: Won't oils become rancid? I'd suggest ordering some food grade grease. Or perhaps one of the members of HB in your area can give you some.

Mark

[mp]

my guess is that your grouphead not only is completely gunk out with coffee but the 2 square spindles are not square anymore and they developed and edge
of course mine is just a guess

Actually the previous owner was very diligent in doing backflushes. When I did a couple of backflushes the pressure release fluids came out clean fairly quickly. When I had the parts disassembled they actually looked mint ... other than the fact that the "Drain Valve Assembly" valve did not come out by itself and I had to apply some force to achieve that.

[mp]

Post some pictures of what's inside for better advice.

BTW: Won't oils become rancid? I'd suggest ordering some food grade grease. Or perhaps one of the members of HB in your area can give you some.

Mark

Hi Mark ... will attempt to do that later when I get some time as the pictures have to be resized ... and since I do not do that too often it will take me some time.

[mp]

Ok ... today I pulled the first 2 double shots. The first shot had a dry puck. The second shot had a wet one. I don't know whether I was drinking the espresso for a longer time period for the first shot than the second which may have accounted for the wet and dry ... any suggestions?

I did another backflush to check out whether the disassembly had any effect on the drainage. I am happy to report that with the blank portafilter basket after pulling the shot there was that famiiliar drainage occuring at the bottom of the mushroom. Yyyeeaaahhhh! When I took the portafilter off after the completion of the flush this time there was pffsh but it came off quite easily. It would seem that the disassembly as Dan recommended worked wonderfully. Thank you Dan!

Just a note to Stefano ... "grouphead not only is completely gunk out with coffee" ... I did do a backflush last week on it when I discovered the "Drain Valve Assembly" was not opening ... it did clean some coffee grains out from the grouphead ... today when I did the backflush there was very little grinds in the blank filterbasket suggesting that the "grouphead was not completly gunk out".

Now regarding the food grade grease ... how important is it to have instead of the Olive oil over the drain valve assembly? I would like to go as long as I could before having to open it up again ... but on the other hand I don't want any negative repercussions on the machine and espresso.

Thank you.