A red ring for a few cents – and the machine stays tight
O-rings are the cheapest parts in an espresso machine and the ones most repairs depend on. A ring that has lost its resilience looks as good as new: it has only become a few tenths flatter and a touch harder. You only notice it once a damp spot appears, and then you end up looking at the wrong screw.
This ring belongs on the bell, upper position. It is so inexpensive that it is worth keeping a few in stock – if you have one at hand, you save yourself the day of waiting at the next service.
When it is due
Every time the joint has been opened – once an O-ring has been compressed, it does not return to its original shape. Also when the area gets damp, when limescale edges form, or when the removed ring is hard, brittle, cracked or visibly flattened.
At a glance
| Type |
O-ring |
| Colour |
red |
| Installation position |
Bell, upper position |
| Fits |
The model series are not listed in the documentation for number C449900702. Send us the serial number of your machine and we will check the fit. |
| Scope of delivery |
one O-ring |
| Part number |
C449900702 |
| Version |
Original Rocket spare part |
| Installation |
Installation by a qualified technician recommended |
| Brand |
Rocket Espresso |
Important for installation
The ring sits in the water-carrying part of the machine. Before any work, the machine must be disconnected from the mains, depressurised and cooled down. We deliberately do not give step-by-step instructions here – an O-ring that gets twisted or pinched when fitted will not seal from the start.
Who it is for
For service workshops with the number from a service document, and for anyone who orders the sealing rings together with an overhaul rather than reordering them one by one.
What goes with it
Its counterpart is the red O-ring for the lower bell. We also carry the O-ring for the foot, the O-ring for the steam valve and water tap and the copper sealing ring for the heat exchanger. Everything else under Rocket accessories and spare parts and Service parts.
Workshop tip from Bern and Zurich
In both workshops we have a small drawer just for O-rings, sorted by part number, and we top it up with every order. That sounds excessive until a machine is out of action on a Saturday because of a ring worth a few cents. This is our workshop routine, not a manufacturer requirement. For dialling in after a service we use Nutty Delight, for chocolatey notes Cozy Chocolate and for body Very Nutty. All roasts under Coffee beans.
No returns
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, please check the model, year of manufacture and serial number of your machine – or drop us a quick message and we will clarify the fit together. Your rights in the case of defective goods remain unaffected.
Frequently asked questions
What inner diameter and cross-section does the ring have?
The dimensions are not given in the documentation for number C449900702. We make no claims about them. Order by part number and you will get the right ring.
What material is it made of?
That is not documented either. The colour is red – the documentation says nothing more.
How do I know which of the two bell rings I need?
By its position: C449900702 sits at the top, C469900422 at the bottom. If you are unsure, send us a photo of the removed rings.
Can I use an O-ring from the DIY store?
We advise against it. In the machine, material and temperature resistance matter, not just the diameter – a ring made of the wrong material will harden and leak.
Can I see the part in the showroom?
Yes, you can see it in person in Bern at Gerberngasse 44 and in Zurich at Hagenholzstrasse 50b.
Questions? Write to [email protected]. Delivery across Switzerland and to Liechtenstein in 2-4 working days.
