Welcome back to the Technician’s Dispatch. Guided by the wisdom of the La Marzocco Home team, we venture even further into the world of espresso craftsmanship. Today, as the light of a solitary red temperature bulb fades, and the flash of a blue light grows seemingly brighter and brighter, we prepare to delve deeper into the arcane mysteries of home espresso machine care. Our story begins at the corner of expectations and reality…

The Mystery of the Hissing Vacuum Breaker

A Mysterious Morning Mist…

by Kimberly Franklin, La Marzocco Home Solutions

Dawn breaks, and with the first light, you slip into your cozy slippers, making a beeline for the espresso machine. It stands there, a beacon of your morning ritual. 

But as you approach, something feels amiss. The machine, usually warm and inviting, feels cold. The ‘refill reservoir’ sign blinks at you. Odd, you think.

Maybe in the evening haze, you forgot to refill it. You top it up, waiting for the familiar hum of the machine warming up. Everything appears to be normal, so you make yourself your favorite morning drink. 
Settling down with a spooky movie in the background, you savor the rich flavors of your espresso. This? This is what the morning is all about…

something’s amiss…

But then, a faint sound interrupts your perfect moment – the pump, running ever so briefly. Brushing it off, you continue with your day. Yet, the sound returns, more insistent this time. “Nevermore! Something’s not right,” you mutter.

Being the astute home barista you are, you decide to play detective. The gauges are totally normal, but there is an unmistakable sputtering, a soft hiss… a ghost perhaps? You cautiously lean down, peering into the shadowy depths of the drip tray. More water than usual. You slide the reservoir out and find some water lurking on top of the lid—the reservoir you just filled is suspiciously low.

You decide to call in the experts. Who do you call? The La Marzocco Home After Sales Team. You detail the peculiarities: the unusual water consumption, the hissing…

Their response is swift: 

“After the day’s final brew, ensure the drain tray is void of water, replenish the reservoir, and mark its level. Leave the machine on throughout the night. By dawn, if the reservoir water has dropped considerably, a steam leak from the vacuum breaker might be the culprit.”

The troubleshooting seems easy enough, you make your last cup of the day, empty the drain tray, note the water in the reservoir and leave it on. As the first light of morning pierces the darkness of your slumber, you discover the reservoir’s water has dropped, accompanied by that unsettling, pestering hiss and gurgle. Drats!

You follow up with the Solutions Team…

“That sounds pretty indicative of a vacuum breaker! The vacuum breaker has a lifespan of about 6- 18 months and other than the portafilter gasket, one of the most commonly replaced maintenance parts on your machine. You can purchase and replace this part yourself, but ,generally, when this fails, indicates time for an annual maintenance service“

The vacuum breaker? What dark secrets does it hold?

The Vacuum Breaker

The vacuum breaker is a maintenance item and it sits on the steam boiler. It is a small valve that is open until the machine has enough steam pressure  to close it. If you listen closely when you turn on your machine from a cold start, as your machine heats, you should be able to hear the breaker hiss as the boiler pressurizes and then the breaker closes. On cool down, as soon as the steam pressure drops below the air pressure in the room (atmospheric pressure) the vacuum breaker opens, preventing a vacuum from forming inside the tank. 

When this part starts to fail, the vacuum breaker never fully closes, thus you get the steam leak. Which means:

  • constant refilling over the reservoir
  • steam/condensation into drain tray (or on top of reservoir since steam can condense)
  • constant sputtering/hissing noise

It is important to note that the vacuum breaker failing does not put the machine at high risk, but the problem certainly doesn’t get any better. It is advised when you have a failing vacuum breaker, to simply turn off the machine when you’re done using it for the day as we do not want constant steam hitting the drain tray which can cause it to become brittle and crack. 

You think about replacing this part yourself, but realize it may be best for the professionals to service this machine. You reach out to inquire about a tech near you…  and to think it would have gotten away with it too, if it weren’t for you meddling baristas. 

As always, if you ever have any questions, don’t hesitate to reach out. Our Home Solutions team is the best in the business. You can email them at [email protected]