Rocket O-ring for the water nozzle – two francs against the damp spot
It is the most inconspicuous item on the entire spare parts shelf and one of the most common reasons for a workshop visit that would not have been necessary. An O-ring on the water nozzle hardens, loses its preload, and suddenly, every time you draw hot water, a drop sits where none belongs.
This O-ring is the original from Rocket for the water nozzle of the Appartamento, Giotto, Cellini and Mozzafiato, part number C400003008. Replacing it takes longer to explain than to do.
When it is due
When the water nozzle stays damp even though the tap is closed. When the O-ring looks hard, brittle or flattened on removal. And as a rule at every service where the nozzle is off anyway – a new ring costs less than a second attempt.
At a glance
| Type |
O-ring, wear part |
| Installation location |
Water nozzle |
| Fits |
Rocket Appartamento, Giotto, Cellini and Mozzafiato |
| Scope of delivery |
One O-ring |
| Part number |
C400003008 |
| Specification |
Original Rocket spare part. We have no documentation of the inner diameter, cross-section thickness or material for this number. |
| Brand |
Rocket Espresso |
Who it is for
For anyone who maintains their Rocket themselves and prefers to have small parts in the drawer before they are needed. An O-ring sitting on the shelf has never ruined a Saturday morning.
The O-rings and sealing rings in the Rocket catalogue
Rocket fits a whole range of O-rings in the steam path, water path and boiler that look very similar from the outside. For most of them, the documentation gives neither the inner diameter nor the cross-section thickness – they can only be reliably told apart by the part number. That is why we list them individually, with the number in the title or in the table:
-
O-ring steam and water tap – A449904334
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O-ring for the cap of the steam and water tap – A449904672
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O-ring rotary knob steam and water, Cellini and Giotto – C400002786
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O-ring water nozzle, Appartamento to Mozzafiato – C400003008
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O-ring 3-way valve – M449907403
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O-ring S2 valve – M449907143
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O-ring 4250 silicone, R9 – M449905837
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O-ring 3187 Viton, R9 – R499907384
-
O-ring drain elbow, Boxer, RE A and R9 – M449905463
-
Copper sealing ring heat exchanger – C479900673
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O-ring boiler top, Porta Via – A449906261
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O-ring boiler bottom, Porta Via – A449906262
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O-ring heating element, Porta Via – A449910266
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O-ring 18 × 5 mm machine foot, R Cinquantotto – A449906954
If you measure your removed part and don't know the number, send us the model and serial number – we will check it against the exploded view.
What goes with it
The Rocket O-ring steam/water nozzle 6x1,2 mm covers a different spot – check which one sits in your machine before ordering. To clean the wand, use Puly Milk Plus Liquido. Everything else under Rocket accessories and spare parts.
Tip from our café
We always fit O-rings with a touch of food-grade silicone grease – that way the ring slides into its groove instead of twisting during assembly. A twisted O-ring seals at first and tears after a few weeks. This is our workshop routine from Bern and Zurich, not a manufacturer specification. For dialling in afterwards, we use Nutty Delight, Cozy Chocolate for chocolatey notes and Very Nutty for maximum body. All roasts under Coffee beans.
Returns excluded
Service parts are excluded from exchange and return. They are procured specifically for each order and cannot be resold after installation or a test fitting on the machine. So before ordering, check the model, year of manufacture and serial number of your machine – or drop us a quick message and we will check the fit together. Your rights in the case of defective goods remain unaffected.
Frequently asked questions
How many O-rings do I need?
One per water nozzle. Many people put two aside at a service – the second costs next to nothing and saves the next order.
Does the ring also fit the steam tip?
Not necessarily. For the steam or water nozzle with 6x1,2 mm we stock a separate part. If in doubt, send us a photo of the spot.
Do I need tools?
Usually no more than a spanner for the nozzle and a delicate touch. Never put pointed tools directly against the ring, otherwise the new one is damaged straight away.
Does it fit an R58?
This part is listed for the Appartamento, Giotto, Cellini and Mozzafiato. For the R58 we stock other seals.
Can I see the part in the showroom?
Our showrooms in Bern (Gerberngasse 44) and Zurich (Hagenholzstrasse 50b) show a wide selection, but not our entire range – the display changes. Drop us a quick line at [email protected] before your visit, and we will check whether the product you have in mind is currently there.
Questions? Write to [email protected]. Delivery across Switzerland and to Liechtenstein in 2-4 working days.
