The valve that lets air in as the machine cools – and is therefore never screwed shut
When an espresso machine cools down, the steam in the boiler contracts and a vacuum forms. The vacuum valve then opens and lets air in. Without this function, the machine draws water back to where it doesn't belong, and the steam wand spits the next time it heats up.
You can hear the valve when it's working: a short hiss shortly after switching off, a soft sucking sound after a few minutes. If this sound is missing or the valve drips constantly instead, it's due for replacement. This item has the part number L192.03 with a 1/8 inch connection.
When it's due
The valve constantly drips or hisses during operation, even though the boiler should be under pressure. The usual sucking sound is missing when the machine cools down. The steam wand spits more than it used to after heating up. Or the valve body is scaled on the outside and can no longer be freed up.
At a glance
| Type |
Vacuum valve, also known as vacuum relief valve |
| Location |
on the steam tap |
| Fits |
Our documentation doesn't name a machine for this item. Send us the serial number and we'll check the fit. |
| Scope of delivery |
one valve. Seals are not mentioned. |
| Part number |
L192.03 |
| Version |
1/8 inch connection, non-rotatable. Material and dimensions are not documented for us. |
| Installation |
Installation by a qualified technician recommended |
| Brand |
La Marzocco |
Important for installation
The valve sits at a point that carries steam. Work only on a machine that is switched off, disconnected from the mains, completely cooled down and depressurised. A vacuum valve is never readjusted, screwed shut, bypassed or seized – it is a safety and functional component, and a machine that runs without it gets damaged. We deliberately don't give step-by-step instructions here.
Two items with the same number
Our documentation lists two vacuum valves for the steam tap, both with the number L192.03 and both 1/8 inch. The difference is only in the item name: one item is explicitly described as rotatable, this one is not. That's why we carry both and name the feature in the title rather than leaving one of them out. If you're unsure which one is fitted to your machine: a rotatable valve can be turned on its axis when installed, a non-rotatable one sits rigidly. If in doubt, write to us – we'll look at it with you before you order.
Who it's for
For workshops and businesses whose machine draws water back after cooling down or spits when heating up. The valve is inexpensive and belongs on the checklist at every major overhaul.
What goes with it
The vacuum valve goes with the rod B.2.013.01, the Teflon insert B.3.001 and the silicone O-ring 102. We carry the rotatable version as a separate item. All other parts are listed under Original spare parts.
From our workshop
In Bern and Zurich, we listen briefly when switching off. If the soft sucking sound comes two or three minutes later, the vacuum valve is working. If nothing comes, we note it for the next service – even if the machine otherwise runs normally. That's our routine, not a manufacturer's specification, but it finds the problem before the wand spits. And afterwards: Nutty Delight, Cozy Chocolate or Very Nutty. More under Coffee beans.
No returns
Original spare parts are excluded from exchange and return. They are sourced specifically for each order and cannot be resold after being installed or test-fitted 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
Why are there two valves with the number L192.03?
That's how it appears in our documentation. One item is explicitly described as rotatable, this one is not – that's the only documented difference. We carry both and say so openly rather than leaving one out.
How can I tell which version I need?
A rotatable valve can be turned on its axis when installed, a non-rotatable one sits rigidly. If in doubt, send us the serial number or a photo and we'll check it.
Can I screw the valve shut if it drips?
No. A vacuum valve is never screwed shut, bypassed or seized. If it drips, it's defective and gets replaced.
Is a seal included?
The documentation doesn't mention one. Before installing, check whether there's a sealing ring on your connection.
Can I see the part in your shop?
Yes. In our showroom in Bern at Gerberngasse 44 and in Zurich at Hagenholzstrasse 50b, we're happy to show you both versions side by side.
Questions about the fit? Write to us at [email protected]. Delivery across Switzerland and to Liechtenstein in 2-4 working days.
