Our Valued Sponsor
OpinionsConsumer ReviewsGuides and How TosCoffeeGeek ReviewsResourcesForums
Espresso: Espresso Mods and Restorations
Giotto, broken 'Breaker Valve'?
Learn @seattlecoffeegear
Learn all about coffee, watch videos, read how-to articles.
www.seattlecoffeegear.com
 
Not Logged in: Log In to Postlog in
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered  
Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Discussions > Espresso > Espresso Mods > Giotto, broken...  
view previous topic | view next topic | view all topics
Author Messages
DariBer
Senior Member
DariBer
Joined: 4 Oct 2012
Posts: 12
Location: Stockholm, Sweden
Expertise: Just starting

Espresso: ECM Giotto (2005)' Gaggia...
Grinder: mahlköning Vario
Posted Tue Nov 27, 2012, 10:52pm
Subject: Giotto, broken 'Breaker Valve'?
 

I'm new into Giotto machines so I'm not familiar how the behaviour of the machine is.

As soon as I turn on my ECM Giotto from 2005 I hear a sound like air pressure leakage and the sound doesn't stop, it's still there after like 20min. After some time I can see some water round the "Breaker Valve" (C219900560), have seen a site called it "Anti-Vac Valve" and after a while I can see some water under the Giotto.

I was wonder if it could be so that the "Breaker Valve" at the top of the boiler is broken and making the air pressure and water  leakage?
back to top
 View Profile Link to this post
calblacksmith
Moderator
calblacksmith
Joined: 25 Nov 2007
Posts: 7,722
Location: Riverside, Ca, U.S.A.
Expertise: I live coffee

Espresso: ECM Vene. A1, La Cimbali M32
Grinder: Azkoyen Capriccio, Major
Vac Pot: 40s era Silex
Drip: Msl. Com. brewers
Roaster: gave it a try, decided no
Posted Wed Nov 28, 2012, 7:20am
Subject: Re: Giotto, broken 'Breaker Valve'?
 

I did not look up any of the references but from your description, it sounds like the vacuum breaker or anti siphon valve is likely dirty. It is designed to open when the boiler pressure drops below that of the air around it. It will not seal again until the boiler is generating pressure and the valve is pushed closed by the steam passing through it. If there is some dirt or something stuck in it, it will not seal and it will leak just as you describe.

I once bought a two group commercial machine for scrap value as the seller said it "would not hold pressure" . The problem turned out to be a chunk of dirt in the vacuum breaker valve. To "fix" the issue, I simply turned the machine on and when it was generating positive pressure, I gave the stem of the valve a few twists to clean the seal and the valve seat and presto, the machine stopped leaking and it has been working well ever since. That may be all you need to do, give the valve stem a twist to clean the seat/seal when the boiler is under pressure. Be careful though, you are dealing with live steam and it is VERY hot, posing a real possibility of getting burned.

If that fails to seal the valve then you will need to replace it but even then this is not an expensive or hard repair to do.

 
In real life, my name is
Wayne P.
Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!

Feed the newbs, starve the trolls and above all enjoy what you drink!
back to top
 View Profile Visit website Link to this post
DariBer
Senior Member
DariBer
Joined: 4 Oct 2012
Posts: 12
Location: Stockholm, Sweden
Expertise: Just starting

Espresso: ECM Giotto (2005)' Gaggia...
Grinder: mahlköning Vario
Posted Wed Nov 28, 2012, 7:51am
Subject: Re: Giotto, broken 'Breaker Valve'?
 

You wrote that the "anti siphon valve". Sorry but I'm not sure if it's my English, never heard of this part. Could you explain what this do or is there also another name for that part?
back to top
 View Profile Link to this post
dyqik
Senior Member


Joined: 7 Oct 2011
Posts: 383
Location: Cambridge, MA
Expertise: I love coffee

Espresso: Bezzera BZ07 PM
Grinder: Baratza Virtuoso Preciso...
Vac Pot: Cona D
Drip: Bona-Vita, CCD, Aeropress.
Roaster: Gene Cafe, Modded Poppers
Posted Wed Nov 28, 2012, 7:56am
Subject: Re: Giotto, broken 'Breaker Valve'?
 

Anti-siphon Valve is another name for the Vacuum Breaker Valve.  It's the same part.
back to top
 View Profile Link to this post
DariBer
Senior Member
DariBer
Joined: 4 Oct 2012
Posts: 12
Location: Stockholm, Sweden
Expertise: Just starting

Espresso: ECM Giotto (2005)' Gaggia...
Grinder: mahlköning Vario
Posted Wed Nov 28, 2012, 8:06am
Subject: Re: Giotto, broken 'Breaker Valve'?
 

Oh, thanx for the explanation.
back to top
 View Profile Link to this post
calblacksmith
Moderator
calblacksmith
Joined: 25 Nov 2007
Posts: 7,722
Location: Riverside, Ca, U.S.A.
Expertise: I live coffee

Espresso: ECM Vene. A1, La Cimbali M32
Grinder: Azkoyen Capriccio, Major
Vac Pot: 40s era Silex
Drip: Msl. Com. brewers
Roaster: gave it a try, decided no
Posted Wed Nov 28, 2012, 11:01am
Subject: Re: Giotto, broken 'Breaker Valve'?
 

Sorry for that.
Yes, they are the same thing with different names with each name describing what the valve does.

The big picture description of what the valve does follows:
Two things happen in a boiler depending on the temp of the boiler.

In Heat Exchanger machines (and non PID controlled Double boiler machines), the temp of the boiler is regulated by the pressure inside the boiler. There is a direct relationship at sea level between pressure and temp in a closed boiler so by regulating  the pressure in the boiler, you can then regulate the temp.

Starting at room temp with a closed boiler, there is air inside the boiler because the water level is not full to the top, this space is needed to provide space for the steam to gather so it can be used when the boiler is in operation.

If you heat the boiler with that air trapped inside, the air, as it warms up expands and causes pressure inside the boiler. This is not steam pressure but it is air pressure. The Pressure stat only measures pressure and can not tell if pressure is from steam or air.

As the air heats and causes pressure, the pressure stat PSTAT senses this pressure and turns the heater off too soon thus the water has not heated to the desired temp. Your vacuum breaker allows this false air pressure to bleed out of the system so that it can not trigger the Pstat to turn the heater off. The water continues to heat and it starts to boil. As it boils, it generates steam at a faster rate than the vacuum breaker can pass, causing the vacuum breaker to seal and then the boiler can build steam pressure and be properly regulated for temp by the Pstat.

Now, at operating temp, the boiler is closed and has pressure. When you turn the machine off, the boiler cools to room temp. As the boiler cools the water contracts and the steam returns to it's water state. If the boiler is forced to stay sealed, a negative pressure (vacuum) will form in the boiler as the cold water takes up much less space than the hot water / steam takes up. There are only a few ways into the boiler, one is through the brew group, one is through the water fill/pump circuit and if there is a steam wand, through the steam wand system and a hot water wand is the same if the machine has one.

This negative pressure or vacuum wants to be filled by the air pressure of the surrounding air. If there is a leak or weak valve in the steam wand, air can go backwards through the steam wand and into the boiler. If there is milk in the steam wand, it will be sucked back into the boiler and that is not a good thing.

If the boiler has a vacuum breaker/anti siphon valve then when the pressure in the boiler drops to the same pressure as the air around it, the valve opens because there is no longer any pressure on it holding it closed. It is a gravity valve so it falls open when the pressure in the boiler reaches 0.

Now that the valve has opened, it will provide the easiest way for air to enter the boiler and prevent a vacuum and thus prevents air from siphoning through the steam wand.

So there you have it, the two names of the same part, which can be used interchangeably.

 
In real life, my name is
Wayne P.
Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!

Feed the newbs, starve the trolls and above all enjoy what you drink!
back to top
 View Profile Visit website Link to this post
DariBer
Senior Member
DariBer
Joined: 4 Oct 2012
Posts: 12
Location: Stockholm, Sweden
Expertise: Just starting

Espresso: ECM Giotto (2005)' Gaggia...
Grinder: mahlköning Vario
Posted Fri Nov 30, 2012, 8:19am
Subject: Re: Giotto, broken 'Breaker Valve'?
 

I changed the valve now but I have forgot the behavior of the Giotto and the vacuum valve, when the machine has raised the pressure to and it's about to turn of the heater I can hear some air coming out of the valve and then it stops. I think this is the way it should work or?
back to top
 View Profile Link to this post
calblacksmith
Moderator
calblacksmith
Joined: 25 Nov 2007
Posts: 7,722
Location: Riverside, Ca, U.S.A.
Expertise: I live coffee

Espresso: ECM Vene. A1, La Cimbali M32
Grinder: Azkoyen Capriccio, Major
Vac Pot: 40s era Silex
Drip: Msl. Com. brewers
Roaster: gave it a try, decided no
Posted Fri Nov 30, 2012, 9:20am
Subject: Re: Giotto, broken 'Breaker Valve'?
 

I'm not real sure of what you are saying.

The valve is opened by gravity and closed by steam pressure. The boiler must be to boiling temp before it starts to generate steam but there will not be pressure in the system until the valve closes. Normal operation of the valve is pretty quick. Not long after steam starts to show out of the valve, it will make a sound sort of like FFFFFFFFFFFFFFFSSSSSSSSSSSSST. with a kind of sudden pop or stop at the T end of the sound. This is the valve sealing. It should not have any steam leak from it after this point. The pressure can not build up in the system until it closes so there can not be any pressure on the gauge (bar of pressure) but if you have a PID or digital readout, you will see boiling temp on the gauge just before it closes but again, after it closes, it should be sealed.

 
In real life, my name is
Wayne P.
Anything I post is personal opinion and is only worth as much as anyone else's personal opinion. YMMV!

Feed the newbs, starve the trolls and above all enjoy what you drink!
back to top
 View Profile Visit website Link to this post
view previous topic | view next topic | view all topics
Discussions > Espresso > Espresso Mods > Giotto, broken...  
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered     Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Not Logged in: Log In to Postlog in
Discussions Quick Jump:
Symbols: New Posts= New Posts since your last visit      No New Posts= No New Posts since last visit     Go to most recent post= Newest post
Forum Rules:
No profanity, illegal acts or personal attacks will be tolerated in these discussion boards.
No commercial posting of any nature will be tolerated; only private sales by private individuals, in the "Buy and Sell" forum.
No SEO style postings will be tolerated. SEO related posts will result in immediate ban from CoffeeGeek.
No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum.
Who Can Read The Forum? Anyone can read posts in these discussion boards.
Who Can Post New Topics? Any registered CoffeeGeek member can post new topics.
Who Can Post Replies? Any registered CoffeeGeek member can post replies.
Can Photos be posted? Anyone can post photos in their new topics or replies.
Who can change or delete posts? Any CoffeeGeek member can edit their own posts. Only moderators can delete posts.
Probationary Period: If you are a new signup for CoffeeGeek, you cannot promote, endorse, criticise or otherwise post an unsolicited endorsement for any company, product or service in your first five postings.
Rancilio Silvia - How to
Step by step guide for easy brewing and steaming with the Rancilio Silvia
www.seattlecoffeegear.com
Home | Opinions | Consumer Reviews | Guides & How Tos | CoffeeGeek Reviews | Resources | Forums | Contact Us
CoffeeGeek.com, CoffeeGeek, and Coffee Geek, along with all associated content & images are copyright ©2000-2014 by Mark Prince, all rights reserved, unless otherwise indicated. Content, code, and images may not be reused without permission. Usage of this website signifies agreement with our Terms and Conditions. (0.223224878311)
Privacy Policy | Copyright Info | Terms and Conditions | CoffeeGeek Advertisers | RSS | Find us on Google+