The small O-ring that seals the LEVA's backflush path
An O-ring the size of a shirt button sits on the backflush screw, and as long as it stays elastic, you don't notice it at all. It seals the path through which water and pressure are led back through the brew group during backflushing. Only when it hardens does water leak out at the side during backflushing, and the pressure no longer builds up properly.
Under recurring heat and movement, rubber loses its elasticity over time – and with daily care, the backflush screw is moved regularly. That is why this ring is one of the parts that are replaced on a scheduled basis. We do not know of a part number for it: it is listed neither in our spare parts list nor in the catalogue we otherwise take the numbers from. We don't make one up.
When it's due
- Water leaks out at the side of the screw during backflushing.
- The pressure no longer builds up cleanly during backflushing.
- The ring is hard, dull, cracked or flattened in one spot.
- The screw has to be tightened much more firmly than before to stay sealed.
- The ring was pulled out along with the screw at the last service and is damaged.
At a glance
| Type |
O-ring for the backflush screw |
| Installation location |
On the backflush screw of the brew group |
| Fits |
La Marzocco LEVA and machines with Smart Steam, as the item name states. Send us the model and serial number and we'll check the fit. |
| Scope of delivery |
One O-ring. The backflush screw itself is not included. |
| Version |
Original La Marzocco. Inner diameter, cord thickness and material are not documented to us. |
| Installation |
Installation by a specialist recommended |
| Brand |
La Marzocco |
Important for installation
The ring sits on a component that carries hot water under pressure. Only work on the machine when it is switched off, cooled down and depressurised. The seat must be clean before the new ring goes in, and the ring must not be dragged over a sharp edge when fitting it – a single nick will make it leak again straight away.
We deliberately do not publish step-by-step instructions here. If you're unsure, have the replacement done by a service technician.
Who it's for
For everyone with a LEVA or a machine with Smart Steam whose backflush screw no longer seals. And for workshops that, when servicing the brew group, routinely replace the small seals as well instead of reinstalling the old ones.
What goes with it
From our workshop in Bern and Zurich
Whenever we have a backflush screw out anyway in Bern and Zurich, a new O-ring goes in, even if the old one still looks usable – the part costs less than a second trip to the machine. And we briefly place the new ring in warm water before fitting it; that way it slides over the edge without being dragged. That is our routine, not a manufacturer specification. We pull the test shot afterwards with Cozy Chocolate or Nutty Delight, and for body without acidity with Very Nutty. All our roasts are listed under coffee beans.
No returns
Original spare 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 line and we'll clarify the fit together. Your rights in the event of defective goods remain unaffected.
Frequently asked questions
How can I tell that the O-ring is due?
If water leaks out at the side of the screw during backflushing or the pressure no longer builds up cleanly, the ring is the most common cause.
What are the dimensions of the ring?
The inner diameter and cord thickness are not documented to us, so we don't state any. Send us the model and serial number and we'll identify it for you.
Does the ring also fit other places on the machine?
We don't claim that. For the LEVA we also carry a set of O-rings in six sizes; we're happy to work out with you which one goes where.
What is the part number of this part?
We do not know of a number for this O-ring, and we don't make one up. If you have a number from service documentation, send it to us so we can cross-check it.
Can I look at the part in your showroom?
Yes. Come to our showroom in Bern at Gerberngasse 44 or in Zurich at Hagenholzstrasse 50b, and we'll show it to you on the machine.
Questions about the fit? Write to us at [email protected]. We deliver across Switzerland and to Liechtenstein in 2-4 working days.
