The steam tap of your Cellini – so that steam comes on command again and stops on command
The steam tap is the part you turn for every cappuccino. Inside, a spindle sits on a sealing seat, and both work against heat, pressure and limescale every time you use it. As long as everything is right, you notice none of this: you open it, the steam comes immediately and at full strength, you close it, and all is quiet.
When the sealing surface wears out, the feel of the knob changes long before anything drips. The tap turns stiffly or suddenly too easily, you have to close it more firmly than before, and in the end it keeps hissing quietly even though you closed it long ago. A complete tap resets spindle, seat and gaskets in one go, instead of replacing one wear part after another.
When it is due
When a fine thread of steam or a hissing remains after closing. When water or steam escapes at the shaft as soon as you open it. When the knob has become stiff, jerks or turns further than it used to. When you need force to close it tightly – that is the moment the seat is giving way.
At a glance
| Type |
Steam tap, complete assembly |
| Installation position |
Steam side of the machine, between boiler and steam wand |
| Fits |
Rocket Cellini |
| Scope of delivery |
The scope is based on the manufacturer's specification for number A899904634. A steam wand and a steam tip are not included. |
| Part number |
A899904634 |
| Version |
Original Rocket spare part |
| Installation |
Installation by a specialist recommended |
| Brand |
Rocket Espresso |
Important for installation
The tap sits in the pressurised steam path. Before any work, the machine is disconnected from the mains, depressurised and allowed to cool down completely – even a cold boiler can still hold residual pressure afterwards. We deliberately do not provide step-by-step instructions here: a poorly seated screw connection starts leaking under pressure, and you only notice when it is too late. Have the replacement done by a specialist or send us the machine.
Who it is for
For Cellini owners whose steam tap no longer closes cleanly, and for service workshops that want to get a machine sealed again in a single pass, instead of working on the shaft and gaskets in two stages.
The steam and water taps in the Rocket catalogue
We list the taps and valves by model. These items belong together:
What goes with it
The O-ring for the steam and water knob for Cellini and Giotto and the knob itself belong to the same corner of the machine. The steam wand for Appartamento, Cellini, Giotto and Mozzafiato connects directly to it. You can find all parts for your model under Rocket Giotto and Cellini spare parts and Original spare parts.
Workshop tip from Bern and Zurich
Our rule is: after frothing milk, just close the tap, do not tighten it. Anyone who cranks it down every time flattens the sealing seat and will need exactly this part within two years. This is our workshop routine, not a manufacturer requirement. For dialling in afterwards we use Nutty Delight, for chocolatey notes Cozy Chocolate and for body Very Nutty. All roasts under Coffee beans.
Returns excluded
Original spare parts are excluded from exchange and return. They are sourced specifically for each order and cannot be resold after installation or a test fit on the machine. So before ordering, check the model, year of manufacture and serial number of your machine – or send us a quick message and we will check the fit together. Your statutory rights regarding defective goods remain unaffected.
Frequently asked questions
Is this a solenoid valve?
No. This is a purely mechanical, manually operated tap with no coil and no electrical connection. It is opened and closed with the knob.
Is the knob included?
The documentation for number A899904634 does not say so clearly. Write to us before ordering and we will clarify the scope of delivery with the manufacturer before you order.
Does the tap also fit a Giotto or Mozzafiato?
This item is listed for the Cellini. For Appartamento and Mozzafiato we carry the tap A229905784 as a separate item. If in doubt, send us the serial number and we will check the fit.
Can I replace the tap myself?
We do not recommend it. The part sits in the pressurised steam path, and a leaking screw connection only shows up under operating pressure. We recommend installation by a specialist.
Can I see the part in the showroom?
Yes, in Bern at Gerberngasse 44 and in Zurich at Hagenholzstrasse 50b you can see it in person.
Questions? Write to [email protected]. Delivery across Switzerland and to Liechtenstein in 2-4 working days.
