Krups EA8250: Brewing punch pushes up

Posted by: Kaffeematz November 27, 2014 08:34 am

Hello together,
my Krups has been standing on my workbench for some weeks now.
Always when I find time I test and try something new to get the machine running again.

The problem:
The upper brewing stamp almost completely pushes out of the brewing chamber during the rinsing process (and thus probably also during the brewing process). The first O-ring is then completely visible.
Naturally, the water in the brewing chamber then splashes past the brewing piston into the interior of the machine.
The actual coffee outlet at the top of the brewing stamp does not produce a drop of water.

The problem has already been described several times here in the forum.
I have implemented or tested all the points mentioned there, unfortunately without success.

work so far:
- Drainage valve checked and relubricated
- Hose Drainage valve brewing chamber flushed
- Seals of the entire brewing unit replaced
- Hydraulic cylinder dismantled, springs cleaned, new spring steel ring fitted on top (the old one was only available in a few parts), completely fitted with new seals, greased and reassembled
- Water filter cleaned
- Water distributor opened, cleaned and reassembled
- The Crema'dichtung' in the brewing stamp and the sieve in the brewing stamp checked and cleaned

On the problem:
The upper brewing punch is pressed out of the brewing chamber as described above.
Interestingly enough, nowhere water is lost in the machine.
- The hydraulic cylinder is completely sealed at the top and bottom
- At the water distributor also no water outlet
- Also the drainage valve is sealed

Does anyone have an idea what else I could check?

>I basically have only one idea left: to replace the pump.
- Because the pressure in the brewing chamber cannot be too high, otherwise the water pressure would open the crema'valve' in the brewing head and rinsing water would come out of the coffee spout.
- A leak in the hydraulic cylinder should be visible, after all more than 2 drops of water should leak out
As you can see, my assumptions are so correct?

What makes me hesitate:
The dilemma with the machine started with a 'hanging' brewing stamp. The brewing ram got stuck in the brewing chamber and so neither the coffee cake nor the drawer was released.
This problem was solved after cleaning the water distributor and the general overhaul of the hydraulic cylinder.
After the problem with the hanging brewing ram was solved, the problem described here occurred during the test rinse.
Up to the problem with the hanging brewing ram, however, the machine always ran without problems.
Why should the pressure generated by the pump suddenly no longer be sufficient?
That speaks for me again rather for a pressure loss in the hydraulic cylinder.
But where does the pressure/the water go?

Or maybe I installed the springs incorrectly in the hydraulic cylinder and generate too much pressure up?
Could someone send me a picture of a working hydraulic cylinder? I can only find pictures of disassembled cylinders, but they don't give much information about the assembly or the place of the springs.

By the way, it's a pity that such a good machine is so susceptible due to a few cent material costs saved.
2 Euro more invested and the machine would work 10 years without problems. Quality is very rare today

Thanks in advance for every idea and tip!

Posted by: kaffeechris November 27, 2014 09:26 am

Hello, I don't know if one of these pictures will help you.

Posted by: kaffeechris November 27, 2014 09:29 am

or

Posted by: Kaffeematz November 27, 2014 11:21 am

MoinMoin,
yes perfect, thanks for the quick answer and the pictures!
That helps me a lot. Now I know for sure that I installed the springs correctly.
One uncertainty factor less!
Many thanks!

Do you still have an idea what could cause my problem?

Thank you and greetings

Posted by: rudi-03 November 27, 2014 06:26 pm

Hello,

The water distributor may be leaking internally. Maybe this post will help.

Posted by: barfly November 28, 2014 12:07 am

Hi,

for me this reads as if you made a mistake with the water distributor itself! Here you should start again and check if you did everything right during the assembly.

Only the XPs had problems with the water distributor, since the EAs I leave my fingers off the distributor.

When I took the distributor apart, I know that the gearwheels have to be installed in a certain arrangement to each other. If you have swapped a position there, it comes to such an error as described by you.

Posted by: Kaffeematz November 28, 2014 12:01 pm

Hello together,
many thanks for the link and the experiences concerning the water distributor.

In fact it is hardly possible to assemble the distributor incorrectly at the EA. Everywhere there are recesses etc, which should prevent a wrong installation.
But due to the described experiences I will disassemble the part again and reassemble it meticulously.
Afterwards I try to find possible leaks. Maybe water from the hydraulic cylinder actually pushes itself into the distributor and from there into e.g. the drip pan.
Both sounds logical and plausible to me. Thanks for the ideas!!
I will report.

A question still to the ceramic inserts in the distributor.
Do these have to be lubricated somehow with silicone grease or the like?br>In one thread I had once read something about silicate gel or something similar. After a cleaning this is of course no longer available.
Must or should this be applied, or is silicone grease sufficient or simply cleaned and ungreased reinstalled?

Thank you and greetings

Posted by: kaffeechris November 28, 2014 12:32 pm

Yes, I've already opened this WV at the top between the ceramic disks is silicone grease.
Other the ceramic disks will run heavily at some point.
MfG Chris

Posted by: Kaffeematz November 28, 2014 01:48 pm

Super, thanks for the quick reply!
see if I can fix the mistake on the water distributor.
I report!
Greetings

Posted by: Kaffeematz December 01, 2014 02:26 pm

Hello everyone,
I spent more hours repairing my EA on the weekend - unfortunately without success.
The brewing stamp still pushes upwards while filling the brewing chamber until water can escape from the brewing chamber. There is no drop from the actual coffee spout.

I opened the water distributor on the weekend
-
- cleaned
- greased the ceramic discs with silicone grease
- opened the drainage valve again, blown through, greased and reassembled
- and reassembled the distributor with great care
- I hope that the assembly was carried out correctly. But basically you can't do anything wrong with the 'tongue and groove' principle.

In addition, I opened and checked the hydraulic cylinder again. I can't find an error there either.
For safety's sake, but again the question of assembly. The EA8250 cylinder has two loose springs with different diameters inside.
Must both springs be installed between the cylinder base and the spring steel circlip? (That's what I assume and that's how it looks like on the pictures above)
Or the smaller spring in diameter is installed above the circlip and the big spring below the circlip?

I remembered one point while thinking about the problem:
The problems with the machine started abruptly with a brewing stamp that got stuck in the brewing chamber:
/forums/...showtopic=16968
To dismantle the machine and to test it, I had to push the brewing punch back into the starting position several times manually and with a lot of effort.
Do I possibly have damaged a valve or something like that which is no longer tight under pressure?

I am quite helpless and open to any further idea!

Thanks and greetings

Posted by: barfly December 01, 2014 02:50 pm

Mmmm, sounds weird.

If no coffee comes out, I would concentrate on the brewing stamp first.

Evtl. times without sieve and without Cremaventil install and look whether now something comes out. Maybe the sieve is full of lime and coffee residues!?

How many covers does your machine already have?

Posted by: Kaffeematz December 02, 2014 08:08 am

MoinMoin,
without a cream valve I have already tested, then it works.
The stamp is not pushed up and the rinsing water comes out of the coffee spout as it should.
I cleaned the brewing sieve etc. on this occasion. Whereby I must say that this was basically not dirty.

I have not yet checked the number of coffee purchases, I still do.
Won't be much though. I use the machine at home and also there only on weekends and for two persons.
You can see that also in the inner life. Everything still looks very good and I have found almost nowhere coffee powder or dried coffee residues, for example.
D.h. Basically the machine is still top, all the more annoys this defect.

I don't understand it that well.
For me there are only two explanations for pushing up the stamp.
Either
- too little water pressure is built up
- or the water in the hydraulic cylinder is pressed somewhere into the system during filling

>Variant 2 is more likely for me, because until the defect of the hanging pressure cylinder (=blocked protective compartment) the pressure was never a problem. So why should suddenly too little pressure be built up?

Against variant 2 it speaks that
- I have no water loss in the machine
- and I can't understand where the water displaced from the cylinder disappears. It's not pushed back into the water tank, I've already checked that. Also no water flows into the collecting tray while the piston is being pushed up.
So it can only be distributed in the water distributor and possibly be pushed into the brewing chamber as well.
So it doesn't really sound likely.

So simple and yet so complicated...

Thanks for every further idea!!

Posted by: barfly December 06, 2014 09:17 pm

I had already written a more detailed answer, which probably swallowed the forum software somehow ... well ...

There I am with my Latin at the end. I don't know, guess the water distributor ....

Posted by: kaffeechris December 07, 2014 01:39 pm

I've thought it over, that these travels are coupled I would conclude on a wrong assembly.
I don't have your unfortunately here. The hydraulic cylinder must be explicitly can be that you have forgotten above the lock washer.so open again and look
Mfg Chris

Posted by: Kaffeematz December 08, 2014 09:35 am

MoinMoin,
I'm always thinking about whether the problem has to do with the cylinder.
That's why I took the part on the WE apart again. I can't find any mistake.
The EA has two springs, one thinner and one thicker. Both are installed and are held at the top by a circlip which fits into a groove.
Also no water escapes.

In addition, I made another test:
- rinsing program selected
- waited until the brewing piston has moved completely downwards
- now the inlet or return hose is disconnected directly at the cylinder by means of pliers
- Result:
- the cylinder or the brewing head is pressed upwards anyway.
Conclusion:
The problem is not caused by pressing water from the cylinder back into the manifold.
If this were the case, the cylinder should not have moved upwards in this test.

I therefore think that too little pressure is built up.
>At least the pump as well as the flowmeter are possible for this, correct?

Has anyone got an idea how I can find out if one of the two parts doesn't work correctly anymore?

Many thanks!!

Posted by: barfly December 08, 2014 10:59 am

Sorry, but when I read such working method "hose disconnected with pliers"! This is a mess and now also the hose will be defective (or soon will be).

Now disassemble the pump, then it is at least also in the bucket.



Ne fun aside, I think you've got one or more bugs in there somewhere, the thing can't be rescued! If you slaughtered them, I'd be interested in the control board.

Barfly

Posted by: Kaffeematz December 08, 2014 12:04 pm

Tach,
naja, if a possible cause is that water from the cylinder is pushed back into the manifold there is not much left but to try to prevent the backflow.
Through this simple and quick test I can now be sure that no drop flows back into the distributor.
A cause of error is excluded - and the tube is still intact

Posted by: kaffeechris December 08, 2014 07:39 pm

The pump can be dismantled with a clear conscience, there are instructions for this in the network.
The small ball must still have 4mm (indication of "Looser").
I thought again about this process. Please take some pictures of what you have moontiert so there at the brewing unit, also below so that you can see what.

MfG Chris

Posted by: Kaffeematz December 13, 2014 01:37 pm

Tach,
I didn't have time yet to take care of my EA again and to check the pump.
But I quickly checked how many covers the machine already has: 2773
So basically like new if you look at what other machines have done until the first serious defect.

Posted by: Kaffeematz December 13, 2014 05:20 pm

Sooo, after another 2 hours my EA is working again
I can't say with 100% certainty what was defective at the end.
But I'm pretty sure it was the Flowmeter.
Reason:
After many more tests and one more complete disassembly, I couldn't find a problem with either the water distributor or the hydraulic cylinder.
Nowhere is water leaking.
Also no water from the hydraulic cylinder runs back into the water supply.
Ergo can only be too little pressure in the hydraulic cylinder to withstand the counterpressure of the brewing unit.
Since the pressure is only regulated by the amount of water and not by a pressure sensor or the like, the flowmeter was the main suspect for me.
The pump only came in 2nd place, because it has no possibility to build up enough pressure when the amount of water is too small. So the flowmeter is the first link in the chain that can be responsible for the error.
And behold, after a thorough cleaning the brewing piston suddenly stayed down again and could withstand the pressure in the brewing unit.

Error fixed, machine is running again.

As I have noticed that there are very few pictures of the inner workings of the EA, I will upload a few more below.
Vlt. these together with my quite detailed descriptions will help one or the other with the repair of his Krups.

greeting

Posted by: Kaffeematz December 13, 2014 05:24 pm

Main board (everything connected except the control unit)

Posted by: Kaffeematz December 13, 2014 05:27 pm

Brewing unit (upper and lower brewing piston disassembled):

Posted by: Kaffeematz December 13, 2014 05:29 pm

Water distributor (drive motor already dismantled):

Posted by: Kaffeematz December 13, 2014 05:31 pm

Water distributor open:

Posted by: Kaffeematz December 13, 2014 05:32 pm

Water distributor, gears and ceramics'distributor' removed:

Posted by: Kaffeematz December 13, 2014 05:34 pm

Hydraulic cylinder open:

Posted by: Kaffeematz December 13, 2014 05:36 pm

Hydraulic cylinder, internal piston

Posted by: Kaffeematz December 13, 2014 05:38 pm

Hydraulic cylinder, inner workings, spring steel retaining ring above the compression springs:

Posted by: Kaffeematz December 13, 2014 05:42 pm

Hydraulic cylinder, spring steel ring below:

Posted by: Kaffeematz December 13, 2014 05:43 pm

Hydraulic cylinder and brewing unit from below:

Posted by: Kaffeematz December 13, 2014 05:45 pm

Brew piston above (here with new gaskets, the original gaskets were black):

Posted by: Kaffeematz December 13, 2014 05:47 pm

Drainage valve and water distributor:

Posted by: Kaffeematz December 13, 2014 05:48 pm

And one last picture: the upper part of the hydraulic cylinder in close-up:

Posted by: barfly December 14, 2014 06:48 pm

Super!! I'm glad to see her running again ....

The had really still few references run, there it must still loosely continue! :-)

Posted by: Kaffeematz December 17, 2014 08:18 am

MoinMoin,
yes, thanks, I was also happy, especially about the good coffee at the weekend :-)

yes, when I read here so that with the one or other DeLonghi machine the first problems after > 10000 covers are not even 2800 of my machine already quite puny.
But maybe the part runs now for the next 5 years without problems, then it fits again :-)
greetings and a good week still

Posted by: kaffeechris December 17, 2014 11:38 am

Hello thanks for the message.
As such something completely different than I have thought.
Yes it should probably run again for a long time and if not, you will set it again in motion.
MfG Chris

Posted by: Christian95 September 22, 2023 07:34 pm

Posted by: Gast_koko December 10, 2023 07:56 pm

I had the same problem and after changing all o-rings the machine even broke the metal part holding the piston. After no logical explanation left I made a few tests and noticed that the grinder fills the brewing chamber almost to the edge. With more coffee inside the mechanism has hard time compressing it. When the brewing process starts the excessive coffee provides more resistance to the high pressure water and pushes the piston upwards. After factory settings reset everything works fine. Here is the link to an useful page with the reset procedure explained: https://doctorcafetera.com/en/krups-troubleshooting
Hope it helps.
Cheers!

Posted by: Jay Scott April 21, 2024 02:04 pm

Bringing old post up from the dead.
I seem to have similar issue.

Piston hanger lifting up under pressure, causing water to go everywhere.

New piston. New rings, same problem.

The only way I can get it to brew without leaking is by removing the piston screen and rubber plug.

After cleaning the piston screen and plug I can get it to brew a full cup of water.

As soon as coffee grinds enter camber, the screen gets clogged enough making the piston hanger rise until coffee water sprays.

I dont think it's a flow or pressure problem as it will brew without coffee grins, but what do I know.

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