Our Valued Sponsor
OpinionsConsumer ReviewsGuides and How TosCoffeeGeek ReviewsResourcesForums
Espresso: Questions and Answers
Stabilizing an HX machine’s grouphead
Rancilio Silvia - How to
Step by step guide for easy brewing and steaming with the Rancilio Silvia
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 > Q and A > Stabilizing an...  
view previous topic | view next topic | view all topics
Author Messages
coffeehabit
Senior Member
coffeehabit
Joined: 11 Apr 2004
Posts: 56
Location: Israel
Expertise: I live coffee

Espresso: GS/3
Grinder: Kony
Vac Pot: none
Roaster: manual 1k drum roaster
Posted Sat Feb 11, 2006, 8:58pm
Subject: Stabilizing an HX machine’s grouphead
 

Before I do something really dumb I am posting here an idea I have to see if I have any chances to get it right.

The issue I want to resolve with my HX machine, which is very well illustrated by the excellent How I Stopped Worrying and Learned to Love HXs post by Dan Kehn, is that the grouphead heats up too much.

I initially thought of a dual boiler mod but since I actually don’t really want to go up this path and only want my grouphead to be a bit more stable at a lower temperature and if possible even be able to control it, I came up with this idea.

The change is to add a zoning valve between the boiler and the E-61 group with a bypass.
The valve needs to close when the grouphead reaches the desired temperature and the bypass should be the right size to keep it at the desired temperature.

Actually my attempt is going to be much coarser as I want to use a Normally Closed valve and to get it to close below the desired temperature and let the bypass heat the grouphead a bit higher then my desired temperature. In this way I want to reduce a 6+ oz of flush to 1-2 oz flush and to slow down the heat back.

As a starter I will only install a manual valve and keep my machine on 24*7 so I can measure the grouphead temp. In this way I should be able to reach some balance between the grouphead temp and the valve setting.

Did anyone every try this plot or has any comments?

I need information on what valves I can use and on how to measure the grouphead temp.

This is the schematics of the HX espresso machine with the change I want to try out -

coffeehabit: Stabilizing HX.gif
(Click for larger image)
back to top
 View Profile Link to this post
baldryk
Senior Member
baldryk
Joined: 25 Jul 2005
Posts: 189
Location: Adelaide

Espresso: Expobar Leva
Grinder: Gran Macinino
Roaster: iRoast2
Posted Sun Feb 12, 2006, 5:16pm
Subject: Re: Stabilizing an HX machine’s grouphead
 

Not quite sure I understand danblev - you are adding a bypass route for the hot water or just controlling the thermosyphon flow through the group?

In a perfect world I'd have a thermosyphon restrictor that was wide open until the group had reached optimum temperature, and then a temp sensor partially closed the restrictor to reduce the flow.

This would (in my head) get it up to temp as quick as it currently does, but maintain a slightly lower ongoing group temp.
back to top
 View Profile Visit website Link to this post
kaanage
Senior Member


Joined: 31 Mar 2004
Posts: 1,452
Location: Melbourne, Australia
Expertise: I love coffee

Espresso: Bezerra BZ99, Gaggia...
Grinder: NS MCF, Imat Lux, Cunil...
Posted Sun Feb 12, 2006, 7:38pm
Subject: Re: Stabilizing an HX machine’s grouphead
 

If you are finding the amount of flushing required is massive and the rebound is too fast, then you can get a flow restrictor placed in the E-61 thermosyphon loop to reduce the overheating to a more manageble level. A friend with an Expobar Lever got his supplier to do this for him and it reduced his flush requirements greatly and increased the stability of the group temp as well.

 
do'in it on the cheap
back to top
 View Profile Link to this post
coffeehabit
Senior Member
coffeehabit
Joined: 11 Apr 2004
Posts: 56
Location: Israel
Expertise: I live coffee

Espresso: GS/3
Grinder: Kony
Vac Pot: none
Roaster: manual 1k drum roaster
Posted Sun Feb 12, 2006, 7:38pm
Subject: Re: Stabilizing an HX machine’s grouphead
 

sorry if the post is not clear

you are adding a bypass route for the hot water

No

or just controlling the thermosyphon flow through the group

Yes

In a perfect world I'd have a thermosyphon restrictor that was wide open until the group had reached optimum temperature, and then a temp sensor partially closed the restrictor to reduce the flow.

This is what I want to achive.

I am first trying to get some feedback if there is any experaince doing this type of mod.

Thanks
back to top
 View Profile Link to this post
coffeehabit
Senior Member
coffeehabit
Joined: 11 Apr 2004
Posts: 56
Location: Israel
Expertise: I live coffee

Espresso: GS/3
Grinder: Kony
Vac Pot: none
Roaster: manual 1k drum roaster
Posted Sun Feb 12, 2006, 7:53pm
Subject: Re: Stabilizing an HX machine’s grouphead
 

you can get a flow restrictor placed in the E-61 thermosyphon loop to reduce the overheating

Thanks,

This is prbably what I need :).

Any tips where one of these can be found?
back to top
 View Profile Link to this post
kaanage
Senior Member


Joined: 31 Mar 2004
Posts: 1,452
Location: Melbourne, Australia
Expertise: I love coffee

Espresso: Bezerra BZ99, Gaggia...
Grinder: NS MCF, Imat Lux, Cunil...
Posted Sun Feb 12, 2006, 8:18pm
Subject: Re: Stabilizing an HX machine’s grouphead
 

I'd check with your Expobar supplier (I'm in Australia). Apparently, the original Faema implementation of the E-61 has a dial that lets you adjust a valve which controls the thermosyphon flow.

 
do'in it on the cheap
back to top
 View Profile Link to this post
baldryk
Senior Member
baldryk
Joined: 25 Jul 2005
Posts: 189
Location: Adelaide

Espresso: Expobar Leva
Grinder: Gran Macinino
Roaster: iRoast2
Posted Sun Feb 12, 2006, 8:22pm
Subject: Re: Stabilizing an HX machine’s grouphead
 

The Expobar flow restrictor is probably less sophisticated than what you're after. It's a plastic 'conical burr shaped' washer... with a slightly smaller hole than the pipe diameter.
back to top
 View Profile Visit website Link to this post
coffeehabit
Senior Member
coffeehabit
Joined: 11 Apr 2004
Posts: 56
Location: Israel
Expertise: I live coffee

Espresso: GS/3
Grinder: Kony
Vac Pot: none
Roaster: manual 1k drum roaster
Posted Sun Feb 12, 2006, 11:51pm
Subject: Re: Stabilizing an HX machine’s grouphead
 

Thanks all.

Somehow the additional information helped me in my first step and I found this link -

The WWDP Presents: FrE61nkenstein
back to top
 View Profile Link to this post
marrone
Senior Member


Joined: 5 Sep 2003
Posts: 195
Location: Bakersfield
Expertise: I love coffee

Espresso: Isomac Tea
Grinder: Pasquini, Spong
Roaster: Hot Top, Fresh Roast +
Posted Tue Feb 14, 2006, 8:45pm
Subject: Re: Stabilizing an HX machine’s grouphead
 

Dan,

I think your idea is a sound one for reducing the temp of the group.

Trouble is, the group temp is only part of the picture. The water in the HX in the boiler quickly reaches the same temp as the rest of the boiler - too darn hot. Pulling a shot will send that superheated water straight to the filter basket.

Ted
back to top
 View Profile Link to this post
view previous topic | view next topic | view all topics
Discussions > Espresso > Q and A > Stabilizing an...  
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.
Coffee Kids
Help folks who help folks in coffee producing nations.
coffeekids.org
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. (0.270114183426)
Privacy Policy | Copyright Info | Terms and Conditions | CoffeeGeek Advertisers | RSS | Find us on Google+