does your S1 make this sound?

jbb · Post by **jbb** » Sat Mar 05, 2011 1:53 am

I recently switched out the pump on my S1V1. Here's the new pump.

: DSCF1144.copy.jpg (117.1 KiB) Viewed 39579 times

Anyway, why I initially became concerned about the pump in the first place was that the machine seemed to be making what I took as a strange and variable noise following activation of either the one or two cup brew switches. Over the last week, having the new pump has not changed that; the noise is still there. I spent some time listening to the audio tracks on a number of youtube and other online S1 videos today and don't hear this. So I made some recordings to see if anyone else hears this on their machine. I saved the recordings as .mov so I could upload them. At least on my end, you need to click on the .mov link; the "play quicktime" link does not launch. IIf sound quality is not sufficient using my computers internal mic I can try with my video camera tomorrow.

Recording one. this is what I think the machine is supposed to sound like. the solenoid opens with a click, and you can hear the hum of the motor. there is some sound of water falling into the drip tray and then the solenoid clicks off. And then there are some clicking sounds at the end as I shut off the recording.

[The extension mov has been deactivated and can no longer be displayed.]

Recording two. same as recording one, but during last seconds of the blank shot you can hear a different kind of whoosh, maybe similar to what you might hear with air escaping from a tube under pressure.

[The extension mov has been deactivated and can no longer be displayed.]

Recording three. The whoosh sound starts maybe half way through the blank shot.

[The extension mov has been deactivated and can no longer be displayed.]

Recording four. The whoosh sound is present almost the complete duration of the shot.

[The extension mov has been deactivated and can no longer be displayed.]

On my machine, input line pressure is controlled by a regulator set at 30 psi. The OPV is set at 12.5 bars and the group pressure at just a shade under 9 bars against a static pull. With the new pump (but not the old one) no matter whether the whoosh sound is present or not machine reads a reproducible 9 bars pressure as evaluated on a PF gauge.

Any ideas? Maybe nothing to be worried about but it is bugging me.

chas · Post by **chas** » Sat Mar 05, 2011 8:43 am

As I stated the first time you published the sound with the original pump, I don't hear any sounds that the two V1's I owned didn't make.

The best advice I can give if it really bothers you is to turn up the stereo while you're pulling a shot.

Post by **Endo** » Sat Mar 05, 2011 8:54 am

If it makes you feel any better, here's the sound of my Mini.

http://www.youtube.com/watch?v=8mQrudgO2l8

jbb · Post by **jbb** » Sat Mar 05, 2011 4:32 pm

chas wrote:As I stated the first time you published the sound with the original pump, I don't hear any sounds that the two V1's I owned didn't make.

The best advice I can give if it really bothers you is to turn up the stereo while you're pulling a shot.

OK, that's good. Figured best outcome was that I'd post this and end up feeling silly-which I guess i do. I'll quit being such a mother hen.

Endo wrote:If it makes you feel any better, here's the sound of my Mini.

See yours doesn't make the whooshing WSOUND (Weird Sound Of Undetermined and Nebulous Disposition). Gotta say though, I don't miss the vibe pump. Nice looking shot at any rate; slow and long. On the S1 do you tend to updose and use a triple basket for those or do you keep it around 15-16 g and tighten the grind to get the pull you want? I have not had good results with updosing much beyond 16 g in the double basket but maybe the preinfusion helps with that.

Post by **Endo** » Sat Mar 05, 2011 6:37 pm

jbb wrote:Gotta say though, I don't miss the vibe pump.

Most people don't...until about 3 years on.

jbb wrote:Nice looking shot at any rate; slow and long. On the S1 do you tend to updose and use a triple basket for those or do you keep it around 15-16 g and tighten the grind to get the pull you want? I have not had good results with updosing much beyond 16 g in the double basket but maybe the preinfusion helps with that.

I get ristrettos like the one shown simply by tightening the grind, thumping the PF and nutating with about 30 lbs pressure. This makes for a very tight and restrictive puck and reduces stray spritzers. I still only use about 16.5g in a double basket. Any more than 17g and even without settling techniques I described, you won't have the necessary headspace to make a good shot.

This is my technique, others prefer a finer grind and lighter tamp. This hasn't worked as well for me.

I don't own the triple basket ....yet.

jbb · Post by **jbb** » Sat Mar 05, 2011 8:35 pm

Endo wrote:
jbb wrote:Gotta say though, I don't miss the vibe pump.
Most people don't...until about 3 years on.

jbb wrote:

or in my case the first week! touche. never had a bit of trouble with the little Ulka on Silvia.

bgour · Post by **bgour** » Sat Mar 05, 2011 9:08 pm

I have the exact same "whoosh" sound which has been there the whole time I've owned my S1V1 (2+ years).

I wouldn't worry about it though it though I'm curious to know what it is.

s1v1/S1Flow.php

Post by **Endo** » Sat Mar 05, 2011 10:31 pm

As you may know, I'm not a rotary pump guy, but I am curious as to why nobody is too concerned with this type of noise.

I assume it's the sound of flow through the pump bypass restrictor when the pressure exceeds the 9 bar set point? No?

Could it not also be the sound of caviatation? Which I assume would greatly reduce the life of the pump? Or is that noise very different?

bgour · Post by **bgour** » Sun Mar 06, 2011 1:23 am

Endo wrote:
I assume it's the sound of flow through the pump bypass restrictor when the pressure exceeds the 9 bar set point? No?

Might be, although it happens with no pressure at the grouphead. In fact, it doesn't happen at all with a blind filter in place which is another clue.

Also, on first run it takes about 5-8 seconds before it kicks in. On subsequent runs it's immediately present.

It does sound to me like water running through a bypass or other valve somewhere. It doesn't sound like something wrong, or mechanical (like a bearing or something like that).

If you don't hear it with the vibe then it seems reasonable that it's the rotary pump bypass as you suggest. Unless there's something different about the plumbing on the Mini?

jbb · Post by **jbb** » Sun Mar 06, 2011 2:50 am

I also hear the sound both during a normal shot and when water is just flowing through the group, when pressure should be very low.

If by pump bypass valve you mean the expansion valve on three-way valve number 2 in the water flow diagram, when I hear the sound I don't see discharge here.

Post by **Endo** » Sun Mar 06, 2011 6:48 am

jbb wrote:If by pump bypass valve you mean the expansion valve on three-way valve number 2 in the water flow diagram, when I hear the sound I don't see discharge here.

No. I meant the internal bybass in the pump itself (not shown in the flow diagram but it would look like a little feedback loop around the pump itself).

But if it doesn't happen with the blind basket, that must not be it.

Post by **JonF** » Sun Mar 06, 2011 4:21 pm

Just a FYI--I get that "whoosh" at the start of every shot with my new S1 V2. No idea why, but not too concerned either.

Post by **Endo** » Sun Mar 06, 2011 8:00 pm

I'm still leaning towards some kind of internal cavitation (gas bubbles forming in region of low pressure). Not sure where though (pump? restrictor? valve?).

Someone may need to get out a stethoscope to solve this mystery.

Post by **Louis** » Sun Mar 06, 2011 11:02 pm

IF it is cavitation (http://en.wikipedia.org/wiki/Cavitation), it happens in the pump itself. This has been described in threads on HB. In many cases it was found to be linked to a restriction in the feed line: using larger tubing seemed to resolve the issue.

See the first results of a Google search of HB on the subject: http://www.google.ca/search?q=site:home ... cavitation

Post by **Endo** » Sun Mar 06, 2011 11:20 pm

Louis wrote:IF it is cavitation (http://en.wikipedia.org/wiki/Cavitation), it happens in the pump itself. This has been described in threads on HB. In many cases it was found to be linked to a restriction in the feed line: using larger tubing seemed to resolve the issue.

Yes. It's one of the things the pump designers will warn about since it has an impact on pump life. It wears out the vanes quickly as I understand. This is why I would want to rule it out rather than just ignore it and say "that's normal".

It doesn't sound as bad as say a backward regulator (for example), but is there some other spot in the lines (gicleur, screen, etc) that could be partially blocked and would cause this sound but not quite as loud?

Still, I stand by my first suggestion. Use a automobile stethoscope or plastic tube placed to the ear and try and figure out the source first. Is it really coming from the pump?

jbb · Post by **jbb** » Mon Mar 07, 2011 1:39 am

I backflushed today, listening to see if I heard the WSOUND while pulling against the blank disk. I found that I can hear the sound during the first pull. But after the basket fills with water, I don't hear it on subsequent pulls. However, if I detach the PF, pour out the water, and pull again against the blank, now I seem to restore the tendency to hear the sound. I'm not sure what that may or may not rule in/out, if anything. Never thought about it, but i wonder where the air within the line goes during such a static pull. Out the three way when it opens I suppose.

since i started this mess tried to read a bit on the operation of rotary vane pumps. the basic mechanism seems straightforward, although i start losing the thread in considering what's happening with input/output pressure on either side of the pump. thus, with the linked threads, etc I'm trying to play a bit of catchup. so, is the idea behind the cavitation hypothesis that, even when the pump is just pushing water through the system without external resistance (ie coffee cake), there must be a flow reduction somewhere in the line that causes turbulence within the pump? I'm not sure what it means, but I know that, based on one thing I read on HB, I made sure that the pump I ordered had a "balanced bypass valve".

If I get a chance tomorrow AM I may try to see if I increase the pressure set point of the pump higher than the 12.5 bar of the OPV, does the sound go away. not sure why i think that would make any difference but.....

Post by **JonF** » Mon Mar 07, 2011 8:35 am

Interesting. Just another observation. I have an Americano every morning, so pull a fair amount of water out of the steam boiler. I never hear the sound as the boiler is refilled, do you? So perhaps it is not pump related. Next time I am home during the week, I might just call the techs and Chris's and hold the phone near the machine.

Post by **Endo** » Mon Mar 07, 2011 10:59 am

Sound of the little rotor inside the flowmeter perhaps?

jbb · Post by **jbb** » Mon Mar 07, 2011 12:30 pm

I never hear the sound when the steam boiler is being filled either. Last night I emailed the sound recordings I posted at the beginning of the thread to the service guys at CC. If I hear something back will update with what they have to say.

Post by **Endo** » Mon Mar 07, 2011 1:12 pm

I listened a few more times and I must say it sounds a LOT like flow through a grouphead gicleur (restrictor) and not pump cavitation or a flow meter turning.

I read somewhere there is a gicleur just after the flow meter on the rotary Vivaldi that is used to limit the rotary pump flow just like the one on the steam boiler (can someone confirm this). I think this is where the noise must come from. Perhaps it needs cleaning as well? Is it accessible like the steam boiler gicleur or is it internal?

Post by **JonF** » Mon Mar 07, 2011 2:58 pm

Took me a little work on Google, but then ended up back here at s1cafe!!!
This video sounds a lot like what I hear too (except for the kids in the background

)
Endo is probably right--perhaps a flow restriction until there is adequate back pressure from the puck.
viewtopic.php?f=13&t=1295

jbb · Post by **jbb** » Mon Mar 07, 2011 3:19 pm

Endo wrote:I listened a few more times and I must say it sounds a LOT like flow through a grouphead gicleur (restrictor) and not pump cavitation or a flow meter turning.

To me it definitely sounds like either water or air moving under pressure.

Endo wrote:I read somewhere there is a gicleur just after the flow meter on the rotary Vivaldi that is used to limit the rotary pump flow just like the one on the steam boiler (can someone confirm this). I think this is where the noise must come from. Perhaps it needs cleaning as well? Is it accessible like the steam boiler gicleur or is it internal?

The water flow diagram shows the gicleur for the steam boiler, but I don't see one indicated for the group line....so if its there they don't show it, at least on that rather simplified diagram.

JonF wrote: Endo is probably right--perhaps a flow restriction until there is adequate back pressure from the puck.
viewtopic.php?f=13&t=1295

The sound in this video is definitely the sound I hear. Re flow restriction under back pressure from puck; at least on my machine I hear the sound even when there is no puck-just water flowing though the group is sufficient. Re the group boiler filling up idea on that thread; from Chas' info on a different post, the water goes through the flow meter before entering the group boiler. This would seem to suggest that water flows continually through the boiler every time the brew switch gets activated. But for me the sound is variable, both in terms of whether I hear it or not, and, if I do, when during the shot it occurs.

jbb · Post by **jbb** » Mon Mar 07, 2011 3:39 pm

just a thought while looking at the flow diagram. v2 people, does your in line group pressure gauge show line pressure even when not pulling a shot? I think I read somewhere where this is the case. If so, the solenoid click that you can hear when activating a brew sequence must be solenoid C opening to a position where water can flow through the group. I wonder if there is anything in the operation of the three way valve in this position that might account for the noise. Like air that enters the line from opening the three way to the discharge position variably escaping during the next shot sequence.

jbb · Post by **jbb** » Mon Mar 07, 2011 5:06 pm

Jason at CC service wrote back.

"wish I could tell you for sure where the noise is coming from, but I don’t think it is anything to worry about. This is a common sound on all the Vivaldi machines. Personally I think it is just the sound from water passing through various sized pipes and there is also a small spring loaded chamber the water must pass through which could also be making the sound. If it was the pump cavitating it would be much louder. Water can make some weird sounds when it is pushed through different sized holes under pressure and I think that’s all you are hearing."

So there may not be one answer.

Post by **JonF** » Mon Mar 07, 2011 6:17 pm

Thanks jbb for the followup. My Espresso Vivace Dolce blend came today! Came home and made my new high water mark for home espresso. Wow, so that's what I bought this thing for!

Post by **Endo** » Mon Mar 07, 2011 6:24 pm

Fair enough. We all seem to agree now that it is a flow restriction somewhere that is pretty normal for the Vivaldi (so nobody need worry). Still, I'm very curious as to the source. If it was my machine, I'd have a 2' length of tubing to my ear, listening for the source. Anybody wanna try and pinpoint it?

I still think there is a hidden gicleur there somewhere (which should be looked at and cleaned I assume). Without it, the high flow rate of the rotary pump (10 times higher than a vibe pump) would have the water shooting out the group head like a garden hose.

(Sorry, I just can't leave a mystery partially solved).

jbb · Post by **jbb** » Tue Mar 08, 2011 1:13 am

I'll see if it is possible to pinpoint a particular source for the sound. its the most obvious sound the machine makes so i guess i'm still curious.

re the flow restrictor idea-on the rotary pump models working output pressure is set using an adjustment that is directly on the pump. I don't know the mechanism of the adjustment, but had assumed it basically just controlled resistance to the motor. If that's true, what would be the purpose of an additional downstream flow restrictor prior to the intake for the group boiler?

I'll also email Jason back and ask him what the "small spring loaded chamber" is. Does anyone know of a cut away diagram of the S1 group? I've seen the parts list but not much detail there. Went to the LS website and was blocked by a login/password.

JonF wrote: My Espresso Vivace Dolce blend came today!

I will have to try the Dolce on the S1. After I plumbed in I laid in a 5 lb stash of Redbird, with the idea that it was a good forgiving blend that I was very familiar with and should be able to get good shots right out of the gate. On the S1 the shots look beautiful. In milk they are really very good, very much the peanuts, nougat, and rich chocolate. but, surprisingly to me, as straight shots I am having a hard time. I get the nuttiness, but then there is just this dark dark bitter chocolate, kind of like just putting bakers chocolate in your mouth. very dry and a long aftertaste. if I could squeeze some sweetness out I think it might all work, but can't seem to hit the sweet spot.

jbb · Post by **jbb** » Tue Mar 08, 2011 12:59 pm

Took the front panel off this AM but will need to scrounge around in lab for some better tygon tubing. general impression was that the sound was coming "low" rather than "high". Examined the parts list more closely last night, and, with the aid of google translate, here appears to be the parts that comprise the flow meter assembly.

: v2 flow meter assembly.jpg (83.52 KiB) Viewed 39392 times

1516: 1/4''-1/8" nipple
1470: gasket
275: filter
1626: gigleur super spring
2498: volume counter var 1.15 mm
961: 1/4" male pipet
1625: gigleur super spring
275: filter
276: gigleur power group F = 0.57 mm
4595: teflon seal for gigleur

The parts going into the Mini flow meter are similar, but the filter/spring/gigleur (gicleur, however its spelled) set do not appear to be repeated on the way out the way it is in the v1/v2.

1516: 1/4''-1/8" nipple
1470: gasket
275: filter
1626: gigleur super spring
2498: volume counter var 1.15 mm
961: 1/4" male pipet

: mini v flow meter assembly.jpg (73.06 KiB) Viewed 39392 times

Perhaps this is the "spring loaded chamber" from Jason's email? And Endo, would this be the type of gicleur/flow restrictor you suspected would be in line before the group?

Post by **Endo** » Tue Mar 08, 2011 1:18 pm

Ah Ha! The mysterious 0.57mm brew boiler gicleur (now to be referred to simply as, "part 276")

I'm pretty sure this is where the sound is coming from.

I see it comes with a small screen just ahead of it as well, and spring to hold it in place. The screen should help prevent the small gicleur hole from getting blocked. Still, with all the gicleur issues on machines like the GS/3, I'm suprised I've not heard of any clogging issues on the Vivaldi (with all the shaving bits, etc).

I see the Mini also has a screen (but no gicleur since the flow rate is fine as is). Is this on the inlet side of the flowmeter, to prevent debris from fowling the meter?

Has anyone ever taken the screen or gicleur out to be cleaned?

It would be fun to try a larger gicleur (like 1.0mm perhaps). It would be interesting to see how the increased flow rate changes the shot!

Post by **JonF** » Tue Mar 08, 2011 3:48 pm

As an aside that might be usefull information . . . I wonder what the typical flow rate without the portafilter is? Just the open flow with the pump running? I am at work but chan check it when I get home. [might give an indication of a plugged restrictor without disassembling anything]

jbb · Post by **jbb** » Wed Mar 09, 2011 2:22 am

Endo wrote: I see the Mini also has a screen (but no gicleur since the flow rate is fine as is). Is this on the inlet side of the flowmeter, to prevent debris from fowling the meter?

Yes, it is the inlet side.

Last night I had emailed Jason at CC about the possibility that the gicleur after the flow meter might be involved in making the whoosh sound. Here's what he emailed back; the spring loaded chamber he mentioned previously is where water accumulates in the OPV chamber.

"....The water comes in at this location (the OPV chamber) and has to push open the spring loaded chamber and then from there the water tees off to the inlet valve or to the coffee boiler. As far as the flowmeter it does have the screens to protect it and the inlet valve also has a screen. As long as you are using softened water the screens should be fine. The main reason for them is because sometimes in manufacturing there can be some metal filings left behind that can migrate through the system. I have heard this sound on new machines so I think it is just the way it is designed as water flows through the system."

So the stage is set for an interesting test. Part 256 or area 51/ghost in the machine? With the front off its easy to access these screens and the gliceur. I will drop them, clean them as necessary, and we shall see. Unfortunately, had to go back into work for several hours tonight and its too late to pull out the wrenches and get into it now. Will post back when know something more.

jbb · Post by **jbb** » Thu Mar 10, 2011 1:38 am

Today I had a chance to disassemble the flow meter assembly with the gliceur. here's a picture of the parts and the wee little screens. the 0.57 mm hole in the gliceur is remarkably tiny.

: DSCF1182.copy.jpg (85.45 KiB) Viewed 39342 times

The screens and gliceur did not look especially gunky. Gave them a brief descale, puffed the screens with compressed air, and reassembled. Powered it back up....and....the whoosh sound is still there.

The decision at this point is whether to continue to try and tease this apart or to abandon the effort. I'd be willing to push forward if a reasonable alternative hypothesis could be formulated that involved the operation of a specific part of the machine. At this point, any alternative hypothesis should incorporate the following:

the sound does not occur under line pressure. so the sound either comes from the pump or is a consequence of activating the pump. the sound does not occur when the steam boiler is filling. since the pump is activated at this time, the sound is unlikely to be directly due to the pump. The sound does not occur during a pull against a water filled blink basket; it appear to require water flow through the brew boiler/group. the occurrence and duration of the sound is variable, but when it occurs it sounds remarkably similar each time.

In commenting on Jason's email the other night I made a mistake. In referring to the "spring loaded chamber" he was not meaning the OPV, he meant the chamber where water comes in from the pump, which is just to the right of the OPV in the attached picture that he sent. In looking at the parts list, this chamber appears to be the seating for a backflow valve.

: LASPAZ EXPANSOIN 1.jpg (115.25 KiB) Viewed 39342 times

: backflow.jpg (81.54 KiB) Viewed 39342 times

If I listen hard with the front off from different angles, I think the noise is definitely coming from this region. So i have two questions for those who are wise in the ways of the Vivaldi.

1) Is there anything in the operation of this valve that might differ in response to line pressure vs. activating the pump (since line pressure must obviously be able to push it open). What happens to this valve when the three way discharges after a shot; ie does it snap shut? Any reason to think air would get trapped in here that could cause variable turbulence?

2) What would happen if one tried to operate the machine without the backflow valve? If I could bypass the valve it would be a direct way to test whether it might be associated with the sound.

Post by **JonF** » Thu Mar 10, 2011 8:36 am

Interesting. Thanks jbb for all the photos and diagrams. Will bookmark this thread for sure!
One other observation that i have noted in the last couple days: In the morning I steam the milk for my wife before making the espresso. If I steam milk first, I do not seem to get the whoosh noise when making the espresso.

To my ears, the sound is not so much flow but is something pressurizing.

Post by **Endo** » Thu Mar 10, 2011 1:23 pm

I'm glad to hear you've further isolated the noise.

I don't think my Mini has this backflow valve. Iassume it's another requirement of the rotary pump?

As far as the hydrodynamics are concerned, I can see how it's possible, given a certain flow rate and geometry, there could be sufficient turbulence to result in cavitation formed outside the pump (i.e. bubbles forming at a sharp internal feature or corner as a result of the pressure gradient). Perhaps this the root cause of the noise....and maybe bubbles in the water as well?

I must say, this 4-way fitting area does look suspicious.

jbb · Post by **jbb** » Mon Mar 21, 2011 12:56 am

All I gotta say is, if my doctor ever comes at me with one of these I am clearing out fast. Yikes. Had never seen these before but found one on an auto store clearance shelf for about $5. They work amazingly well. the first time i tried it i made the mistake of putting it directly against the pump. sounds like a jackhammer.

: DSCF1187.copy.jpg (90.22 KiB) Viewed 39241 times

jbb · Post by **jbb** » Mon Mar 21, 2011 1:52 am

anyway, i used the stethoscope to tilt at this particular windmill. the goal was to see if i could hear the whoosh noise emanating from a specific place in the plumbing. after the pump, i then probed the area around the backflow valve and four way junction (in blue in diagram) that seemed possibly suspect for turbulence. nothing real obvious here, although I could hear a bit of a gurgling sound from the valve housing.

once I moved on to the smaller diameter pipe going out towards the flow meter *yellow" the whoosh noise sounded more obvious.

on the other side of the flow meter, past the flow restrictor going out to the brew boiler (red) the whoosh sound was very noticeable, especially right at the restrictor but over the entire pipe really. kind of like the sound a vortex of water makes going down a drain.

: pipe noise.jpg (119.59 KiB) Viewed 39239 times

in all of this its a bit relative. i could always hear the sound throughout the system, it was really a matter of how loud it seemed. but if i had to guess, i'd say the sound is emanating from the pipe going into the brew boiler, possibly just after the flow restrictor. any ideas?

Post by **JohnB** » Mon Mar 21, 2011 10:26 am

Open it up & see if there is a partial restriction. I like that tool! Gonna have to look for one of those.

Post by **Louis** » Mon Mar 21, 2011 3:24 pm

JohnB wrote:Open it up & see if there is a partial restriction. I like that tool! Gonna have to look for one of those.

Isn't a gicleur considered to be "partial restriction" by design?...

Post by **JohnB** » Mon Mar 21, 2011 3:39 pm

Yes & they can unintentionally become "partially restricted" by scale/debris/ect.

Post by **Endo** » Mon Mar 21, 2011 3:47 pm

Those stethescopes are great! Now we really have it narrowed down.

This points back to what we had suspected, the flow near the gicleur. It could just be the noise through the gicleur itself OR perhaps that sharp 90 deg elbow just after the flowmeter exit.

Going back to the original suggestion, I guess you could always try a slightly larger 1.00mm gicleur and see if the noise goes away. (The flow would be different, but that might be fun to try to see what effect it has). You could also try replacing the elbow with a straight section followed by a longer bent copper feed tube.

jbb · Post by **jbb** » Mon Mar 21, 2011 5:59 pm

JohnB wrote:Yes & they can unintentionally become "partially restricted" by scale/debris/ect.

got a few minutes while shifting gears here at work. this possibility came up a bit earlier, leading me to disassemble and try and clean both the springs/screen leading in and out of the flow meter, as well as the gliceur itself. This made no apparent difference in the noise. as far as i could tell, the little tiny hole in the gliceur looked clean.

jbb · Post by **jbb** » Mon Mar 21, 2011 6:05 pm

Endo wrote:Those stethescopes are great! Now we really have it narrowed down.

This points back to what we had suspected, the flow near the gicleur. It could just be the noise through the gicleur itself OR perhaps that sharp 90 deg elbow just after the flowmeter exit.

Going back to the original suggestion, I guess you could always try a slightly larger 1.00mm gicleur and see if the noise goes away. (The flow would be different, but that might be fun to try to see what effect it has). You could also try replacing the elbow with a straight section followed by a longer bent copper feed tube.

it would be fun to try. I spent a small bit of time googling "gliceurs" (which mostly brings up glaciers) and "flow restrictors". nothing like what one would obviously want. where does one find these gliceurs? I could check CC, but at least for me it seems difficult to locate things on their website. Jason had asked me to update him, I suppose he'd probably knows and I'll see what he says. I'll also check espresso parts northwest.

I wonder if it would be possible to replace the copper tubing with flexible plastic somehow, while still installing the flow restrictor. Then could modulate the curvature, etc to examine the effect.

Post by **Endo** » Mon Mar 21, 2011 7:24 pm

jbb wrote: it would be fun to try. I spent a small bit of time googling "gliceurs" (which mostly brings up glaciers) and "flow restrictors". nothing like what one would obviously want. where does one find these gliceurs?

That's because it's spelled "gicleur".

(French for "jet", like on a carb).

If you do a search on HB, you'll get a bunch of hits. Mostly having to do with clogged gicleurs on the GS/3. The standard size seems to be 0.6mm (almost the same as the S1).

I suppose a LM tech might have some. Perhaps espressoparts. Otherwise, you'd probably need to make one.

jbb · Post by **jbb** » Tue Mar 22, 2011 12:20 am

Endo wrote:That's because it's spelled "gicleur". If you do a search on HB, you'll get a bunch of hits. Mostly having to do with clogged gicleurs on the GS/3.

Was going to post back that if I googled it with the correct spelling I just pulled back HB and CG pages with people griping about their clogged GS3s, and that after several such posts reading about glaciers proved much more preferable. But you beat me to it.

Endo wrote:Otherwise, you'd probably need to make one.

Hmmm. Unless this is one of those 1001 uses for duct tape i'm not quite sure how i would go about doing that.

Post by **Endo** » Tue Mar 22, 2011 10:47 am

jbb wrote:Hmmm. Unless this is one of those 1001 uses for duct tape i'm not quite sure how i would go about doing that.

You just need a spare gicleur and a .05mm file.

Seriously though, I can see it would be difficult without the proper tools. I suppose it would require a wire EDM.

Perhaps you can get a slightly undersized pin hole gauge (or needle), and ream it out using an abrasive slurry? (Of course this assumes you can find a spare one since you would want to go back). Maybe Jason can send you a spare for testing purposes?

jbb · Post by **jbb** » Mon Mar 28, 2011 5:30 pm

Re the idea that the whoosh sound is caused by air being evacuated from the vertical pipe between the flow meter and the boiler.

just from the nature of the sound, it seems that movement of air within the pipes could potentially be involved. however, my understanding is that the plumbing between the water intake into the pump and the three way at the group head is always under line pressure. so unless the three way introduces air back into the system when it discharges, not sure where the air pockets would come from. if i have the idea right.

i've got a goal to find a find some flexible tubing with the same diameter as the pipe in question. Then find a way to attach the relevant hard ware and seating for the gicleur (spelled properly i hope) and see what that does. the question is finding the time to locate the parts. should be easy once i have them.

Post by **Endo** » Mon Mar 28, 2011 10:24 pm

jbb wrote:.. my understanding is that the plumbing between the water intake into the pump and the three way at the group head is always under line pressure. so unless the three way introduces air back into the system when it discharges, not sure where the air pockets would come from.

My theory goes like this: There is no vacuum breaker on the brew boiler (unlike the steam boiler), so when the water cools it shrinks and creates a vacuum where air is sucked in somewhere low... in the flow meter area I suspect. The air bubbles then rise up the vertical copper pipe causing it to empty until the next time the water fills the area with water forced through the gicleur.

jbb wrote:.. i've got a goal to find a find some flexible tubing with the same diameter as the pipe in question. Then find a way to attach the relevant hard ware and seating for the gicleur (spelled properly i hope) and see what that does. the question is finding the time to locate the parts. should be easy once i have them.

Ambitious !

jbb · Post by **jbb** » Fri Apr 15, 2011 4:30 am

Endo wrote:My theory goes like this: There is no vacuum breaker on the brew boiler (unlike the steam boiler), so when the water cools it shrinks and creates a vacuum where air is sucked in somewhere low... in the flow meter area I suspect. The air bubbles then rise up the vertical copper pipe causing it to empty until the next time the water fills the area with water forced through the gicleur.

have had house guests and professional commitments. actually, with the temp issues on the s1 seemingly resolved have really appreciated it while having guests. not only am getting reproducibly nice espresso, but cranking out multiple drinks is SOOOO much easier than temp surfing back and forth on a SBDU.

anyway, let me follow up on your idea. i also tend to think air must be getting into the line somewhere (although my bias has been the air is getting in higher up, like at the three way). first, the whoosh noise can be heard on back to back shots. that's not much cooling, hence i'd think not much temp ∆ to create a vacuum that sucks air in. plus, if there was the possibility of air being pulled in at the flow meter, why would water not leak out under line pressure? I have not completely disassembled the flow meter. i imagine it is some kind of impeller that spins around and generates a current. could the spinning be fast enough to create air bubbles through turbulence?

Post by **Endo** » Fri Apr 15, 2011 9:04 pm

jbb wrote: I have not completely disassembled the flow meter. i imagine it is some kind of impeller that spins around and generates a current. could the spinning be fast enough to create air bubbles through turbulence?

I'm pretty sure it's a turbine flow meter where there is a small rotor that spins in the flow and a magnetic pickup counts the number of passing blades, which is proportional to the flow rate. Since the rotor is driven by the flow (not vice versa), I doubt there would be much flow disturbance or separation.