The Teflon ring that keeps the brew group sealed
This flat Teflon washer sits on the relief valve of the Rocket brew group. It seals the point where residual pressure escapes after a shot – a component just a few millimetres in size that still decides whether the pressure stays in the valve or finds another way out.
Teflon is hard and does not spring back. Every time it is screwed down, the ring is pressed a little flatter, and at some point the surface is so deformed that it no longer seals. That is why, when you open the group, you do not put the ring back but replace it. Part number C469900783 identifies it unambiguously – by appearance alone it can hardly be told apart from its siblings.
When it is due
After a shot, water drips from a spot that never dripped before. A damp edge or a film of limescale appears on the valve and comes back after wiping. The group releases pressure hesitantly, and the portafilter only comes loose after a moment. Or, when you take things apart, the ring lies in front of you as a squashed, bowl-shaped washer instead of a flat one – then it has done its job.
At a glance
| Type |
Teflon gasket |
| Location |
Brew group relief valve |
| Fits |
Rocket machines with this brew group – the documentation does not list specific models |
| Scope of delivery |
one gasket |
| Part number |
C469900783 |
| Version |
Teflon (PTFE); dimensions and thickness are not documented |
| Installation |
Installation by a specialist recommended |
| Brand |
Rocket |
Important for installation
The part sits in a pressurised line, right next to the hot water of the group. Unplug the machine first and let it depressurise and cool down. Teflon does not tolerate tightening by feel: if it is tightened too much, the material flows and the gasket fails on the first shot. We deliberately do not give step-by-step instructions here – the group is under pressure, and anyone who opens it should have done so before.
Who it is for
For workshops and for experienced owners who renew all sealing surfaces anyway when servicing the brew group. If you are just chasing a drip and do not know where it comes from, write to us first – the group has several spots where water can escape, and the wrong ring will not solve the problem.
What goes with it
The same service usually calls for: the Teflon O-ring 36 mm for the group, the Teflon gasket for the mushroom-head screw, the upper group valve and the fine filter of the brew group. All Rocket parts are listed in Rocket accessories and spare parts and in Original spare parts.
The Teflon gaskets in the Rocket catalogue
We stock five Teflon gaskets individually. They look alike but sit in quite different places – the part number decides, not the shape:
From our workshop in Bern and Zürich
When we take things apart, we lay the old Teflon rings side by side on a white sheet of paper and write the number next to each one. After half an hour on the workbench they all look the same, and reaching into the wrong box costs more time than writing it down. This is our routine, not a manufacturer requirement. We pull the first shot afterwards with a bean that reveals faults instead of hiding them – for example our Nutty Delight or the Cozy Chocolate. If you like it stronger, take the Very Nutty; the full range is in Coffee beans.
Returns excluded
Original spare parts are excluded from exchange and return. They are sourced specifically for each order and cannot be resold once they have been installed or test-fitted on a machine. So before ordering, check the model, year of manufacture and serial number of your machine – or drop us a line and we will clarify the fit together. Your rights regarding defective goods remain unaffected.
Frequently asked questions
Is this an electrical part?
No. It is purely a Teflon gasket, with no coil, no connection and no electrical function whatsoever.
What are the dimensions of the ring?
Inner diameter, outer diameter and thickness are not documented for C469900783. Send us the serial number of your machine and we will check the fit.
How does it differ from C469900420 and C469900421?
All three are Teflon gaskets on the same brew group, but in three different places. What counts is the part number, not the appearance. The list above shows all five Teflon gaskets in the catalogue.
Can I reuse the old ring?
We advise against it. Teflon does not spring back; a ring that has been compressed once rarely seals as well as before after being refitted.
Can I see the part in your showroom?
Yes. You will find us in Bern at Gerberngasse 44 and in Zürich at Hagenholzstrasse 50b. Let us know shortly beforehand and we will have the part ready.
Questions about the fit? Write to us at [email protected]. We deliver across Switzerland and to Liechtenstein in 2-4 working days.
