Our Valued Sponsor
OpinionsConsumer ReviewsGuides and How TosCoffeeGeek ReviewsResourcesForums
Espresso: Espresso Machines
Alex Duetto 3 pump cavitation when auto filling steam boiler
Barista Tools
Large selection of tampers, pitchers, milk frothers and much more!
www.espressozone.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 > Machines > Alex Duetto 3...  
view previous topic | view next topic | view all topics
Author Messages
schwaggy
Senior Member


Joined: 5 Apr 2013
Posts: 18
Location: Seattle
Expertise: I live coffee

Espresso: Alex Duetto III
Grinder: Mazzer Mini E Type A w/ SJ...
Posted Mon May 20, 2013, 1:26pm
Subject: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

Hi guys

I'm wondering if any of you with Duetto 2 or 3 could record and upload a quick video of how your machine sounds when auto filling the steam boiler, from either the internal tank or plumbed?
I have a 2 month old Duetto 3 that is starving for water, but only when auto filling on the steam side. Mine is plumbed but the cavitation sound is the same whether plumed or pulling from tank.

I've been working with Chris' for a couple weeks taking things apart and checking for clogs, but we're simply not getting anywhere and I'm getting a bit weary of taking the cover off and wrenching my new machine.
So far, I've removed the fill valve and cleaned the piston and mesh filter on the intake side. Of course they were not dirty since the machine is so new. I also checked as much copper pipe as was easy to remove before things got too tight for tools.
The machine is plumbed and behind a Watts regulator providing 3 bar static pressure to the machine. The same cavitation occurs whether the pressure is .05 bar or 6 bar, or when pulling from tank.

I was hoping to do a comparison of how other machines sound when auto filling to help determine how bad off I am, and what to do next.

Here's 2 videos clearly demonstrating the pump when my Duetto is filling the steam boiler. Brewing through the group is fine, no issues with the pump.
http://schwaggy.com/pump/Resources/pump.mov
http://schwaggy.com/pump2/Resources/pump2.mov


Many thanks!
back to top
 View Profile Link to this post
emradguy
Senior Member
emradguy
Joined: 31 Mar 2011
Posts: 2,744
Location: Houston
Expertise: I live coffee

Espresso: Duetto II; Twist v2
Grinder: M Major, 2 Macap M4s, OE...
Drip: Espro presses; Aeropress
Roaster: H-B "List of Favorites"
Posted Mon May 20, 2013, 2:35pm
Subject: Re: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

Well...hard to help you off the top of my head, as any recollection of what my DII sounds like is with the case on...but it's definitely different, deeper and more full sounding and without the buzz - though I suspect most of that has to do with resonation inside the steel box. I'd love to record it for you, but to be honest probably won't get to for a couple of days. I hope someone else can help you sooner than that.

 
.
Always remember the most important thing is what ends up in your cup!
back to top
 View Profile Link to this post
SStones
Senior Member
SStones
Joined: 24 Nov 2012
Posts: 452
Location: Canada
Expertise: Professional

Espresso: Giga 5, ECM Giotto, Rocket...
Grinder: Anfim Milano-Best
Vac Pot: No  :(
Drip: Some $30 thing from Walmart
Roaster: I buy pre-roasted.
Posted Mon May 20, 2013, 8:44pm
Subject: Re: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

If it happens for both the plumbing and the reservoir, then it's most likely the part common to both sources, the intake of the pump itself. My guess is that something's gotten into the pump inlet and is preventing adequate flow.
Were it not occuring with the watertank as well, I'd strongly suspect the regulator. What sort of flow is it rated for?

Step one is going to be to take the inlet line off of the pump, turn the water supply on and see if the flow rate is decent.  With the inlet open, look inside. Hopefully your blockage will have come out of your line or your pump by this point.

If the flow to the pump is more than adequate and there's nothing in the inlet physically blocking it, then step two will be to reconsider whether the pump is starved for water or making noises for a different reason.
back to top
 View Profile Link to this post
DavecUK
Senior Member


Joined: 21 Sep 2005
Posts: 1,326
Location: UK
Expertise: I love coffee

Posted Tue May 21, 2013, 4:21am
Subject: Re: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

The links to your videos point to files of 365 bytes, which is far too small, so they are not working.
back to top
 View Profile Link to this post
schwaggy
Senior Member


Joined: 5 Apr 2013
Posts: 18
Location: Seattle
Expertise: I live coffee

Espresso: Alex Duetto III
Grinder: Mazzer Mini E Type A w/ SJ...
Posted Tue May 21, 2013, 9:29am
Subject: Re: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

DavecUK Said:

The links to your videos point to files of 365 bytes, which is far too small, so they are not working.

Posted May 21, 2013 link

Thanks Dave, I was hoping you'd take a look.
The URL's are not links to downloadable files, rather streaming movies.
They should play seamlessly in your browser. I'm guessing you might have a QuickTime browser plug-in issue.
Check your install and let me know: http://support.apple.com/downloads/#quicktime
I'll help you troubleshoot so you can offer some advice!

@SStones - if I had an issue at the pump inlet, wouldn't it manefest at steam boiler refill AND drawing from the brew boiler? I have no issues or cavitation when brewing, only when the steam boiler is filling...
back to top
 View Profile Link to this post
emradguy
Senior Member
emradguy
Joined: 31 Mar 2011
Posts: 2,744
Location: Houston
Expertise: I live coffee

Espresso: Duetto II; Twist v2
Grinder: M Major, 2 Macap M4s, OE...
Drip: Espro presses; Aeropress
Roaster: H-B "List of Favorites"
Posted Tue May 21, 2013, 9:51am
Subject: Re: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

yes, the video links worked fine when I opened them.

 
.
Always remember the most important thing is what ends up in your cup!
back to top
 View Profile Link to this post
SStones
Senior Member
SStones
Joined: 24 Nov 2012
Posts: 452
Location: Canada
Expertise: Professional

Espresso: Giga 5, ECM Giotto, Rocket...
Grinder: Anfim Milano-Best
Vac Pot: No  :(
Drip: Some $30 thing from Walmart
Roaster: I buy pre-roasted.
Posted Tue May 21, 2013, 6:47pm
Subject: Re: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

schwaggy Said:

@SStones - if I had an issue at the pump inlet, wouldn't it manefest at steam boiler refill AND drawing from the brew boiler? I have no issues or cavitation when brewing, only when the steam boiler is filling...

Posted May 21, 2013 link

Pump cavitation occurs when the pump is drawing enough of a vacuum at the inlet to be moving small bubbles of partial vacuum (Very low pressure, gaseous water) over the vanes and through moving parts. It is usually recognizable as that pecking/banging/popping noise of the vacuum pockets being pulled and then slamming back out of existance.
Cavitation is going to happen in a pump if it is able to move more water out than it is supplied with. I suppose it is possible that the downstream restrictions of the brew circuit are enough to prevent the pump from exceeding its volume when brewing despite a partial inlet blockage. The inlet blockage could be minimal enough to allow that (Possibly) while still allowing the higher-flow, unrestricted boiler-fill outflow to exceed available inlet flow.  Not likely, but if you're sure your pump is suffering starvation under some circumstances I'd check the inlet flow before doing much more testing. Cavitation will pit and damage your pump a bit more if continued.

If/when you ensure the inlet flow is adequate, listen carefully elsewhere, at the steam boiler, for one. It might be a noise related to the boiling of the water, or something.  Sorry if I'm way off base, I can't be sure without checking things, first.  How would it be possible for your inlet supply flow to change between brew and boilerfill? There's only one pump in that machine.
Is there some safety-redundancy solenoid valve on the inlet that opens when the pump runs?
back to top
 View Profile Link to this post
DavecUK
Senior Member


Joined: 21 Sep 2005
Posts: 1,326
Location: UK
Expertise: I love coffee

Posted Wed May 22, 2013, 11:27am
Subject: Re: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

Theres a few possibilities if indeed it is cavitation, to fault find.

  1. Change the brew pressure to 7 bar, try it, then 10 bar and try it, does it change the noise?
  2. Run the pump dry for a few seconds, does it still make a noise?
  3. When you reintroduce water to the pump, you will hear it cavitate for sure, is this the same noise your hearing
  4. The hoses to the pump have a plastic inner, check that this is not kinked and allow free flow of water, it's possible it's blocked or PTFE etc.. has got in the inlet. You will have to remove it to check this.
  5. remove the outlet hose as well, Loosen the pump clamp and carefully lift the pump away, is it dry in there?
  6. Try and spin the pump on the shaft, it will be slightly stiff, but otherwise should move freely, does it grind or catch
  7. Look inside the holes, can you see anything in there.
  8. Spin the motor shaft, it should spin freely and continue turning for a while.

The reason it won't make the noise whilst brewing is the flow demand is very slow due to the restriction (Gicleur) in the E61 group (which makes cavitation to water starvation much more difficult), but of course the flow is far higher into the steam boiler.....

Do the tests, be gentle, careful with the PTFE when you reassemble and let me know what happens. I've listed the tests in PITA order to do, so if you get an interesting result by test 3, post back before going on to later tests.


P.S. I had forgotten, this is a new PC and I had not installed QT yet....videos OK now.
back to top
 View Profile Link to this post
schwaggy
Senior Member


Joined: 5 Apr 2013
Posts: 18
Location: Seattle
Expertise: I live coffee

Espresso: Alex Duetto III
Grinder: Mazzer Mini E Type A w/ SJ...
Posted Wed May 22, 2013, 1:22pm
Subject: Re: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

DavecUK Said:

Do the tests, be gentle, careful with the PTFE when you reassemble and let me know what happens. I've listed the tests in PITA order to do, so if you get an interesting result by test 3, post back before going on to later tests.

Posted May 22, 2013 link

Thanks so much Dave, I'll try and get things started on the weekend.
In the meantime, did you watch and listen to my videos? How does it sound to you?
Is there any possibility of you uploading a clip of a Duetto when auto filling so I at least have some comparison?
back to top
 View Profile Link to this post
DavecUK
Senior Member


Joined: 21 Sep 2005
Posts: 1,326
Location: UK
Expertise: I love coffee

Posted Wed May 22, 2013, 6:12pm
Subject: Re: Alex Duetto 3 pump cavitation when auto filling steam boiler
 

It sounds noisy, but it's difficult to know. It depends on how sensitive the mic is, how accurate the sound reproduction is (as my system could change things). I suspect there might be some restriction to flow, but lets see after the tests. A Duetto autofilling, doesn't make the sound yours does, if there is cavitation due to something like the antibackflow valve scaled up and letting by, then the cavitation is usually brief, a second or 2 and then it stops as water is bought back into the pump circuit. It's also a much harsher sound than you are getting.

Lets see after some tests.
back to top
 View Profile Link to this post
view previous topic | view next topic | view all topics
Discussions > Espresso > Machines > Alex Duetto 3...  
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.
Quality Espresso Machines
Imported Italian Espresso Machines, Coffee Machines & accessories for all your coffee needs!
www.thecoffeebrewers.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. (0.541480064392)
Privacy Policy | Copyright Info | Terms and Conditions | CoffeeGeek Advertisers | RSS | Find us on Google+