In my quest to learn as much as possible about not only espresso brewing but how the machines themselves work, I've been reading a lot about the purpose of the vacuum breaker and its various applications. One thing that surprised me is why we still see machines where the vacuum breaker is not routed to the drip tray or water tank. For example, on my QM V2B the vac breaker has a silicone line that's routed to the drip tray. On say, a Profitec Pro 800, the vac breaker has no such line and will spew water onto the boiler until it seals. Is there a technical reason why this design was chosen?

I would assume that decision is always based on cost.

Ira

My Victoria Arduino Leva has a small copper cup brazed to the boiler around the vac valve. I thought that a nice touch. My previous 2 machine had nothing.

Hello:

I have a ca. 2000 Cimbali D/1.
After seeing how the vapour sputter from the vacuum breaker would eventually condense in hard to access places which were still relatively cold (eg: the hard to reach part of the neck where the group meets the boiler) I made myself one of these from some copper AC stuff I had laying around:



It's sealed at the top with a coin I found that was just the right size and fits over the edge of the valve.
I later made the rubber hose (from an auto store) longer and weighed it with a small length of thin walled SS pipe so that it would hang vertically just about 1" above the drip tray.

Works great.

Cheers,

CIV

Almico wrote:My Victoria Arduino Leva has a small copper cup brazed to the boiler around the vac valve. I thought that a nice touch. My previous 2 machine had nothing.

So on a "cost in no object" type of machine, the anti-vac is not drained. In your case, extra care was taken to somewhat encapsulate it. That's probably more money than just running a silicone line to the drip tray. So there must be some reason why they don't do it. I'm asking for no other reason than genuine curiosity. Design of espresso machines has turned into a fun offshoot of this new hobby I find myself in.

As an aside, Almico, can't wait to visit your cafe if I'm ever in the area!

I have thought about this too. Clearly the decision to route the vac breaker or the boiler emergency pressure relief valve to the drip tray is a better design and engineering choice. Innovation can be hard to accept, look at all these E61 machines!

I'm not an Italian espresso machine designer but I had a couple thoughts.

1. It's an anti-vacuum valve, not an anti-vaporlock valve. Sure, it also functions to prevent vapor lock, but that can be accomplished just by opening the steam valve while the machine heats up. On the other hand, vacuum inside a pressure vessel could be a problem as it cools down.

2. Most espresso machine designers have been building commercial machines for most of their careers. Only in the last decade or so have they given thought to machines for home use. In a commercial machine that is rarely turned off 15 or 30 seconds a month of steam release doesn't really seem very important, at least compared to the daily heating and cooling cycle of home users. Eventually the engineers will come around, but it took automotive designers almost a century to recognize the vital necessity of cupholders.

I have an Italian espresso machine wherein the vacuum breaker outlet is neatly routed to the drip tray by a silicone tube and a little downward directed outlet spout. So there is no lack of understanding of the need, or of simple ways to move water around, by Italian or other designers of machines with steam generating boilers. The tiny cost/labour time won't be an issue on more expensive, hand built machines.

There is probably more than one design of vacuum breaker - some will open up under boiler low pressure and stay open for a while when the boiler is next warmed up. Some will close fast enough not to need condensate piping.

The vacuum breaker on the Bianca stays open for a while and outputs a small amount of vapour across the front of the machine when it does so. It's enough to cloud the gauge front and coat the bottom 10 -20 mm of the machine front with vapour. This all disappears within a a minute or so of the breaker shutting, but it could be a reason for routing it elsewhere or not routing it to the drip tray. Personally I find it quite enjoyable, reminding me of the noise from a warming kettle and telling me that coffee is on its way!

silicone hose routed to drip tray is always preferable, the same applies to safety valve. this saves you from flooding your café in case of failure (overfilling boiler).

I have an 8-10 year old GS3 and I'm told the first thing I should update is the vacuum breaker.... I'm no technician at all and don't know much about espresso machine parts or repairs, but people talk like it can possibly cause some serious damage. What is it that happens that could cause damage? Seems like a major design flaw if this is the case.