Introduction
The gaskets of the brewing unit are heavily used and should be replaced from time to time.
The Siemens brewing unit is identical to units of other brands, e.g. Nivona, Bosch, Melitta.
These instructions may also help with other Siemens/Bosch models and with coffee makers from Nivona, Melitta, and Miele—they have a very similar design.
What you need
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The inside of the brewing unit ist exposed. You can see:
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The upper piston and its gasket.
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The funnel for the coffee grounds
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The lower piston.
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The hold-down clamp
Hi, Thank you for your howto. It is very detailed and helpful.
There is another seal in the lower piston. it seems to be a lip seal.
I searched and couldn't find a remplacement for that. do you know where I can buy it?
Many thanks
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Remove the funnel.
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Rotate the lower piston counterclockwise and lift it off.
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Lift off the upper piston. There ist still a hose connecting the piston to the coffee outlet. In top there ist also the downholder of the brewing unit.
Anyone seen the repairkit somewhere?
we have taken the piston out to replace the gasket, and noticed that 2 of the 3 return springs within the housing surrounding the piston are broken and offset. can we buy these springs as spare parts anywhere? many thanks
Was ist dieser Niederhalter? Wo kann dieses Teil reißen, kannst du mir kurz einen Hinweis geben. Bin mir unsicher auf welches Teil zu verweist. Evtl. könnte man es im Bild farblich markieren. Danke!
Habs jetzt in Bild 5 grün markiert. Es ist wie eine Brücke über dem oberen Kolben. Er trägt auf der Unterseite eine kleine Gummidichtung (kann auch kaputt gehen), die verhindert, dass der Kaffee oben über dem Kolben rausfließt (sondern zum Kaffeeauslauf nach vorne), wenn der Kolben ganz oben ist. Der Riss kommt recht häufig vor; er ist ziemlich unauffällig, du erkennst ihn, wenn du versuchst den Niederhalter zu verbiegen. Eine mögliche Quelle habe ich ja oben am 3.Okt.2020 angegeben.
VauWeh -
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Remove the hose connecting the upper piston and the coffee outlet.
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Remove the upper piston.
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Remove the Torx T20 screw from the screen of the upper piston.
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Take off the cover of the gasket and the gasket.
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Replace the gaskets of the upper piston, the coffee outlet and water connector.
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Clean thoroughly all parts. Use food-proof silicone grease to lubricate the gaskets.
I have no coffee/water coming tru the outlet of the upper piston, i can see water runs into the piston chamber but nothing goes tru. I have changed the drain valve without luck - Any clue of what my problem could be?
Check for a tiny crack in the downholder .
VauWeh -
Well, are you sure that the issue is really with the brewing unit? I would ask someone if they could borrow a brewing unit for testing. As many machines are produced by the same factory and are equally designed (Eugster in Portugal) brewing units from Nivona, Bosch and Melitta will also fit.
VauWeh -
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Remove both screws. Lift off the valve. Inspect it and clean it.
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Note: there is another gasket on the shaft of the lower piston. Replacing it is difficult.
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Lubricate all sliding parts with food-proof silicone grease. Verify the smooth operating of the brewing unit.
Nice article, I’ve renewed the lip seal in the brewing unit but I still don’t get even a drop of coffee in the cup, it all goes in the drip tray.
I have dismantled the brewing unit complete and suspect the lower piston seal to be the problem as it doesn’t provide any “resistance” or tight fit.
You say; “replacing is difficult”, but no instructions. Could you please provide a link?
Many thanks in advance.
And: Did you have a look to the drainage valve?
VauWeh -
Hello. I managed to replace the o-ring for the piston, I mean taking out and installing the new one, using a tool from this kit: YT-08429 .
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To reassemble your device, follow these directions in reverse order.
To reassemble your device, follow these directions in reverse order.
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16 Comments
Très intéressant tutoriel.
Une heure me semble suffisant comme temps nécessaire.
À propos de « Note: there is another gasket on the shaft of the lower piston. Replacing it is difficult », c’est justement ce joint qui semble défectueux. J’ai pu l’enlever et le remettre, mais n’en ai pas trouvé de remplacement (-:
Maybe this one. It’s from Nivona, but the brewing unit is the same:
I have problem with my brewing unit of Siemens EQ 3 S300. Can you have an instruction to open it?
hi there, I have a Melitta solo milk, took apart to clean, now when the coffee moves to top piston water doesn’t get through from chamber to upper piston, cycle ends early and all pressurised mixture falls out. any ideas. many thanks.
Did you replace the gasket? The lip of the piston gasket must point towards the pressure, i.e. downwards. Perhaps you should repeat the whole process?
VauWeh -
Awesome! I manage to clean my filter with this guide. Thank you!
Hi, I appreciate this quide. I managed to disassembly and reassembly unit after cleaning. I tried clean it all because the machine stopped working and is in the same state as "dtdt" user indicated above:
The process description:
Press butten, the grinder prepars the portion of coffee.
The unit moves the piston up, the pump injects water and makes pressure.
At this point, the machine used to stop for a while and proceeded with coffee to the cup.
Now, the process is interruped with water and coffee wasted out.
I tried other functions like steam and hot water production but both work well, so the waterpump looks functionable.
Also during the shutdown process, the cleaning water runs out of the machine normally.
Could anyone add some hint what might be wrong, please?
Thank you, Jan
Do you know anybody with the same type of brewing unit (Melitta, Siemens, Bosch, Nivona)? Replace the unit by another to proof, if the issue is in the brewing unit. Another possibility would be a defective drainage valve.
VauWeh -
I managed to find the same coffee machine with deffective grinder. Surprisingly the second machine behaves also the same way when grinders are swapped.
I swapped also the brewing units, but the result is exactly the same.
So probably there is something else causing the issue.
I also cleaned and and reassabmled the draining valve part. I found no obvious mechanical issues there.
This starts looking more electronic logic issue to me.
Would you know what exactly in the process follows the timegap I described originally above? The controll unit might expect some sensoric input to allow the whole process proceed?
Thank you for your time! :-)
jan -
Really really strange. Without sitting in front of the machine it is difficult to get an idea. Did you also check the microswitches of the Drive?
Ok, I identified the microswitch, which is responsible for the process interruption. It is the switch controlled by the crema valve.
I observed that during startup and cleaning the crema valve is lifted ideally, both blobs on the grey plastic controll pod fixed to the crema valve are being moved along the microswitch (the valve operates in the whole working range). During the coffee preparation process, it seems like the crema valve is not moving along the whole operational range (only one blob is fully passed and the second one never makes it to release the microswitcuh.
I experimented with adjusting the angle of the crema valve grey pod - as soon as both blobs on the of the controll pod moved along the whole working range (in the other words when the microswitch was properly releaaed, the coffee making process passed successfuly.
The question is, why the crema valve cant make it all the way along the controll blobs = why it stuckes with the switch in the closed possition?
Not sure what drives the crema valve.
jan -