Mini Backflushing Problem

Post by **Endo** » Thu Jan 15, 2009 11:16 pm

I got my blind basket and am trying to do a water backflush. I've done many before on my Silvia and Anita, but these never had a flowmeter and fault functions like on the Mini Vivaldi.

In the manual and videos I've seen, it seems lights are supposed to come on, signaling a flow meter malfunction (lack of flow) during a backflush. But on my Mini, these lights never come on. I've tried backflushing with both the single and double cup buttons. I stop the backflush after about 10 seconds to avoid overloading and possibly damaging the vibe pump. The water then shoots out of the 3-way valve, like I'd expect. So at least I know the backflush is working.

Any idea what's going on? Perhaps the Mini doesn't have the flashing lights indication? Can someone verify this on their Mini?

Post by **zoey** » Thu Jan 15, 2009 11:29 pm

On my machine the malfunction lights don't always come on when back flushing; Especially when using a triple basket. However, as you have discovered, black flushing is occurring.

I've found that the warning lights come on consistently if I use the single basket v.s. a double or triple. It makes no difference which shot button (on the machine) that you use.

I talked to Chris's about back flushing and they indicated a duration of 15 seconds repeating the process three to five times. You won't hurt the vibe pump. They are very simplistic and pretty much bulletproof.

Post by **Endo** » Thu Jan 15, 2009 11:38 pm

OK. So it seems it's not just me.

I'm using a blind basket (not a disc) and it's the same shape as my single basket (but without the holes).

I tried letting it run for 15 seconds using the 2 cup button and the lights never came on. I tried again for 15 seconds with the 1 cup dose button and still got no lights.

I'm thinking maybe the logic is not working because the Mini uses a vibe pump. Doesn't really make sense but I can't see any other difference between the Mini and regular Vivaldi.

Well, I guess it's not a huge deal since the backflushing is working. Just seems odd.

Post by **JohnB** » Fri Jan 16, 2009 8:58 am

Endo wrote:OK. So it seems it's not just me.

I'm using a blind basket (not a disc) and it's the same shape as my single basket (but without the holes).

I tried letting it run for 15 seconds using the 2 cup button and the lights never came on. I tried again for 15 seconds with the 1 cup dose button and still got no lights.

I'm thinking maybe the logic is not working because the Mini uses a vibe pump. Doesn't really make sense but I can't see any other difference between the Mini and regular Vivaldi.

Well, I guess it's not a huge deal since the backflushing is working. Just seems odd.

Zoey also has a Mini with the vibe pump & his lights flash so I think you can forget that theory. Are you seeing any water leaking by the p/f? It takes 8 seconds for the warning flash to start on my S1.

Post by **Endo** » Fri Jan 16, 2009 10:45 am

Well....he says the lights come on inconsistantly. So I won't discount the vibe pump just yet. Mine might just take a bit longer than the 15 seconds I've done so far (although it seems very long to me).

I don't see any leaking around the PF (and no puddles anywhere else).

I assume the fault logic works my detecting no flow past the flow meter after a certain amount of time. Is this correct? Anywhere else the water could be leaking out (or perhaps backflowing or bypassing)?

I have another theory. Could it be the vibe pump pulses are fooling the volumetric flow meter into think there is still a tiny bit of flow? This effect might worse on some machines than others.

Post by **JohnB** » Fri Jan 16, 2009 11:11 am

zoey wrote: I've found that the warning lights come on consistently if I use the single basket v.s. a double or triple. It makes no difference which shot button (on the machine) that you use.

You are only supposed to backflush with a single basket so I'd say his machine is consistant. How long before your warning lights flash if you choke the machine with too fine a grind?

Post by **Endo** » Fri Jan 16, 2009 11:18 am

No lights. Ever. Even when choking.

Yes, I am using the blind single basket for backflushing.

Any thoughts on the vibe pump theory I added to my last post? Any way to tell if the flowmeter is delivering a signal to the control board during backflsuhing?

Post by **JohnB** » Fri Jan 16, 2009 11:37 am

Endo wrote:No lights. Ever. Even when choking.

Yes, I am using the blind single basket for backflushing.

Any thoughts on the vibe pump theory I added to my last post?

Since you seem to be the first to notice the problem I doubt it is typical of a vibe pump. Pull off the top & front covers & check for a disconnected or loose wire in that circuit? If you don't find anything I'd consider it a warranty issue & contact the seller about getting it fixed.

Post by **Endo** » Fri Jan 16, 2009 1:01 pm

No loose wires. I also checked the 3-way outlet just to make sure it wasn't dripping during backflush (before 3-way release). Nothing at all.

I also notice my vibe pump doesn't seem to make the usual "struggling" sound as on my old machines like the Silvia. But perhaps it is a different pump and has a different "blocked" sound.

I don't see why the single, double or triple basket would make any difference. Since water is incompressible, it should just take a bit longer to fill but the lights should still always come on since it has nowhere else to go.

I wonder if they didn't remove this "no flow" fault from the logic on the new Minis. Hmmm..

I'll make a YouTube video and send it to LaSpaziale and Chris Coffee to see what they say. I'd ask my retailer, but I don't think they even know what backflushing is.

In any case, it's not a huge issue. My other machines never had this "no flow" detection, so I don't really miss it (or need it). I'm not sure I'd bother going through the warranty hassle, but I'll see what they say.

MDL · Post by **MDL** » Fri Jan 16, 2009 1:41 pm

Disclaimer: I have a Vivaldi II, not a mini.

Who told you that you are "only supposed to backflush with a single basket"?
I routinely use a blind basket that is a double to backflush.
Mark

Post by **Endo** » Fri Jan 16, 2009 1:54 pm

OK. Here is my video I promised showing the backflushing problem. Let me know what you think.

http://www.youtube.com/watch?v=FpU9a7-03sQ

*** Disregard the sound. It's super loud due to my little crappy camera microphone. The sound is actually much, much quieter.

Post by **JohnB** » Fri Jan 16, 2009 1:59 pm

MDL wrote:Disclaimer: I have a Vivaldi II, not a mini.

Who told you that you are "only supposed to backflush with a single basket"?
I routinely use a blind basket that is a double to backflush.
Mark

I took that from the Owners Manual & you will also note that when you buy a blind basket it is always a single. Maybe they want to limit the amount of water being flushed through the valve at any one time or maybe it doesn't make a damn bit of difference.

MDL · Post by **MDL** » Fri Jan 16, 2009 2:26 pm

As stated in my initial post in this thread, my purchased blind basket is a double; purchased blind baskets are not "always a single". For the mini (with a vibe pump) it may be important to use a single, but for a standard Vivaldi it is not required.

Post by **JohnB** » Fri Jan 16, 2009 3:35 pm

MDL wrote:As stated in my initial post in this thread, my purchased blind basket is a double; purchased blind baskets are not "always a single". For the mini (with a vibe pump) it may be important to use a single, but for a standard Vivaldi it is not required.

Then I stand corrected, where did you buy the blind double?

Post by **zoey** » Fri Jan 16, 2009 5:26 pm

Yea, where did you get the blind double?

Ok, so I just did a back flush on my machine and my memory was reversed (sorry).

I did 6 back flushes in a row using a combination of the single and double shot buttons. I tried varying lengths of time (15 to 30 seconds). In every instance, no warning lights came on and the board remained lit just as yours did in the video.

I did notice that the pump didn't make a drastic noise change, as it sometimes will do when I choke the machine with too fine of a grind. It's when the machine gets choked that the warning lights will come on, but not all the time.

Post by **JohnB** » Fri Jan 16, 2009 5:35 pm

When doing a back flush does you group pressure climb as high as when you pull a shot(9b)?

Post by **Endo** » Fri Jan 16, 2009 5:48 pm

zoey wrote:
Ok, so I just did a back flush on my machine and my memory was reversed (sorry).

I did 6 back flushes in a row using a combination of the single and double shot buttons. I tried varying lengths of time (15 to 30 seconds). In every instance, no warning lights came on and the board remained lit just as yours did in the video.

Ahhh...that makes sense now.

zoey wrote: I did notice that the pump didn't make a drastic noise change, as it sometimes will do when I choke the machine with too fine of a grind. It's when the machine gets choked that the warning lights will come on, but not all the time.

On the other hand....that doesn't make any sense. Choking is the same as backflushing, just using coffee instead of a blind basket.

I sent an e-mail to Chris Coffee and La Spaziale. The guys at Chris says they get the same thing as me. They say nobody ever noticed it before ( I feel honored

). Just goes to show how many people actually backflush I guess.

They're going to contact La Spaziale to see it's the programming or the vibe pump and expansion valve design itself. I'll keep you posted.

Post by **zoey** » Fri Jan 16, 2009 10:46 pm

On the other hand....that doesn't make any sense. Choking is the same as backflushing, just using coffee instead of a blind basket.

What I mean is that the pump will suddenly get very quiet, which I believe might be the pressure on the outgoing side equalizing with the movement and pressure of the plunger (I don't know what it's called. The piece within the pump that vibrates back and forth between the two springs causing water pressure).

Maybe it would just be easier if I were to videotape what I'm talking about?

Post by **Endo** » Fri Jan 16, 2009 11:38 pm

zoey wrote:What I mean is that the pump will suddenly get very quiet, which I believe might be the pressure on the outgoing side equalizing with the movement and pressure of the plunger (I don't know what it's called. The piece within the pump that vibrates back and forth between the two springs causing water pressure).

Sorry Zoey, I don't get what you mean. If you put a single blind basket, double blind or fine coffee, it's all the same. You stop the flow out the brew head.

I've been thinking about this a bit more. I'm starting to wonder if the OPV is not AFTER the flow meter. This would mean that water would come out of the brew head up to the 9 bar OPV limit, but when blocked, the excess pressure (above 9 bar) would be released by allowing flow out the OPV and back to the steam boiler.

This means you would continue to get flow past the meter (even when the brew head is blocked) and would also explain why the vibe pump is not struggling so much.

I guess we'll see what CC and LaSpaziale have to say.

Post by **JohnB** » Sat Jan 17, 2009 8:47 am

Endo wrote: I've been thinking about this a bit more. I'm starting to wonder if the OPV is not AFTER the flow meter. This would mean that water would come out of the brew head up to the 9 bar OPV limit, but when blocked, the excess pressure (above 9 bar) would be released by allowing flow out the OPV and back to the steam boiler.

This means you would continue to get flow past the meter (even when the brew head is blocked) and would also explain why the vibe pump is not struggling so much.

I guess we'll see what CC and LaSpaziale have to say.

Have you looked at the Water Flow Diagram in the manual? In order for water to flow into the steam boiler Solenoid Valve A would have to open. If your steam boiler is already full I doubt that would happen.

Post by **Endo** » Sat Jan 17, 2009 9:44 am

JohnB wrote:
Have you looked at the Water Flow Diagram in the manual? In order for water to flow into the steam boiler Solenoid Valve A would have to open. If your steam boiler is already full I doubt that would happen.

Yes, very true according to the diagram. I'm just wondering if perhaps the diagram is wrong. And if so, what would it look like to give the situation I am seeing.

I agree that returning OP water back to a full steam boiler doesn't make sense. The OPV is a cold water bypass (like on my Silvia).

I think the most likely scenario is that LaSpaziale removed the fault logic on the Mini due to some issues they may have been having with this "no flow" fault logic and the vibe pump (that is specific to the Mini).

The other possibility is when Solenoid A is open, the vibe pulses fool the flow meter into thinking there is flow.

We'll see what they say.

chas · Post by **chas** » Sat Jan 17, 2009 11:07 am

Endo, it'll take you or one of the other Mini users to pull the covers off your machine, trace all the water lines and connections, and then let me know if any changes are needed for the diagram. That's what I did to create the drawing for the V1 and VII. It's only a guess as to whether the changes I made to the VI/VII diagram to convert it to a Mini diagram are correct.

I don't think there is any possibility that the flow meter is between the OPV and the pump. The flow meter could never perform its main function of volumetric dosing if the flow through it consists of water going to the group AND water flowing back to the pump input.

When we use the flow meter alarm as part of the backflush routine; i.e. to detect choking, we are actually subverting the alarm for a purpose different than intended. When the alarm occurs, it means that the flow meter has gone x sec without detecting at least y oz of water flow (whatever LaSpaz set x and y to be). When the alarm occurs, it is supposed to be a detection that the flow meter itself has failed. That would normally mean water is flowing through it but the volume is not being measured. When we get the alarm due to choking, the flow meter is actually working perfectly and the alarm is really like a false positive.

So it is possible that LaSpaz figured out some way to detect that false positive condition and not trigger on it. That said, I doubt it. It will probably turn out to be a firmware bug, but I'll try to keep an open mind.

MDL · Post by **MDL** » Sat Jan 17, 2009 11:52 am

For those who are interested I bought my blind double basket from Espresso Parts Northwest.

I find it much easier to use compared to the rubber disc.

Mark

chas · Post by **chas** » Sat Jan 17, 2009 12:25 pm

Ditto!

Post by **zoey** » Sat Jan 17, 2009 1:38 pm

http://www.youtube.com/watch?v=uQ2JOmGbPdM

chas · Post by **chas** » Sat Jan 17, 2009 2:07 pm

OK, I've never seen that one before. It looks like, since your backflush disk is not sealing very well, you get enough flow that it just shuts off at the exact same instant the flow alarm lights start to blight.

You found a corner case. I have only seen the following two cases.
1) Complete water blockage. flow alarm lights blink and pump runs until the shot button is pressed again
2) Enough leakage so that the flow alarm never comes on and the pump shuts off normally.

In your case how do you clear the alarm? Run another shot w/o the backflush disk in place?

That blind basket mentioned earlier that's available from EPNW will fix that. While you're at it, order a few LM 58mm PF springs (yes they fit!) so you can stop using that shorty screwdriver to pry out your baskets. Try it, you'll like it!

Post by **Endo** » Sat Jan 17, 2009 3:12 pm

zoey wrote:http://www.youtube.com/watch?v=uQ2JOmGbPdM

Man...that's weird.

Very different from my Mini (which just keeps going when completely blocked).

I'm not sure why your pump stopped. Could it be a combination of PF leakage and a 2 cup volume set very low? Try increasing your 2 cup dose volume to 4 oz and sealing better with a blind basket, then try it again.

Still, I don`t understand how your fault lights come on AFTER the pump stops.

Could it be the vibe pump safety cutoff is kicking in? Or does that just work when the vibe pump is on for a very long time?

Now I'm thinking perhaps La Spaziale discovered the situation you have on earlier Mini models and "fixed" it by disabling the "blocked fault logic" (a carry over "oversight" from the Maxi perhaps) on the the newer models like mine.

Post by **zoey** » Sat Jan 17, 2009 5:34 pm

It looks like, since your backflush disk is not sealing very well

The leak only occurs for 1-2 seconds before a complete seal occurs.

In your case how do you clear the alarm?

The alarm ceases as soon as I stop the pull and no further action is required.

While you're at it, order a few LM 58mm PF springs

I just gave the OEM springs a re-bend. Now they come out quite easily.

I'm not sure why your pump stopped.

It hasn't. IMHO, the pressure has developed to a maximal state, which prevents the 'piston' (for lack of a better term) from vibrating back and forth between the springs. In essence, the 'piston' has become stationary.

Could it be a combination of PF leakage and a 2 cup volume set very low?

It doesn't matter which button I use or the volume.

Could it be the vibe pump safety cutoff is kicking in? Or does that just work when the vibe pump is on for a very long time?

As evidenced by the video, time is not a factor. The vibe pump, as I have seen, is rather simplistic. As I understand it (saw it torn apart on the t.v. show "Deconstructed"), it's basically a 'piston' between two springs. The piston moves (vibrates) back and forth due to magnetic fields.

Therefore, I have my doubts that there would be any need for a safety cutoff mechanism. Once it hits the maximal pressure, the 'piston' just stops moving. No harm would be done due to heat or mechanical stress.

Post by **Endo** » Sun Jan 18, 2009 10:44 am

zoey wrote: IMHO, the pressure has developed to a maximal state, which prevents the 'piston' (for lack of a better term) from vibrating back and forth between the springs. In essence, the 'piston' has become stationary.

Correct me if I'm wrong, but I've never heard or seen a vibe pump "stall" like you are describing on any vibe pump machine I've owned. Has anyone else?

The Mini uses a pump and pressure regulating valve. The valve is set at 9 bar at the factory. When the pressure developed by the pump exceeds 9 bar, the valve opens just after the pump (before the pumped cold water even gets to the brew head)and brings the cold water back to the tank (or just before the pump). This is how the brew pressure is regulated. (You can see this little "bypass loop" in the water flow diagram in the manual). So I can't see how sufficient pressure could be generated to "stall" the pump (it would need more than 15 bar if I am not mistaken).

Since this regulating valve is adjustable, could it be that your brew pressure is set too high? Since you have a VII, I assume you have a brew pressure gauge on the front. What does it read during backflushing?

Post by **zoey** » Sun Jan 18, 2009 11:35 am

10 bar

Post by **Endo** » Sun Jan 18, 2009 12:18 pm

zoey wrote:10 bar

Interesting.

Since there are not many vibe users on this forum (and I'm not 100% sure myself), I'll ask the question on a bigger forum of users:

http://www.home-barista.com/espresso-ma ... t9541.html

Post by **zoey** » Sun Jan 18, 2009 3:38 pm

I just opened up my machine for a quick lesson on water flow. I didn't realize that the expansion valve recirculated overpressure water back to a T-connection between the tank and the vibe pump.

So, what I'm hearing when the noise of the pump changes is water making circles through the expansion valve and vibe pump?

Post by **JohnB** » Sun Jan 18, 2009 6:01 pm

It hasn't. IMHO, the pressure has developed to a maximal state, which prevents the 'piston' (for lack of a better term) from vibrating back and forth between the springs. In essence, the 'piston' has become stationary.
[/quote]

That would also be my theory. Put your hand on the pump if you've still got the covers off & see if its buzzing lightly when the alarm flashes.

Post by **zoey** » Sun Jan 18, 2009 6:47 pm

Sorry, too late. I put the covers back on

I was thinking a little more about it, which usually means that I'll come up with an incorrect conclusion, but; lets say that the pump is happily pumping along. Water is freely flowing through the grouphead.

Then, all of a sudden, the water can no longer flow through the grouphead. At that point, from what I can determine by following water lines within the machine, water would follow the path of least resistance, which would be to the expansion valve (unless of course the pressure required to open the expansion valve is greater than what the pump can produce). From the expansion valve back to the T-connection, and because the pump is still pumping, back through the pump again.

This means that the pump would continue to pump unless there was some electrical cutoff mechanism in place. Having said that, it would also stand to reason that the noise from the pump would remain relatively the same. However, as evidenced by the video, it doesn't. In fact, the pump sound becomes quite dampened.

Just for the sake of hearing myself type, if the water were being diverted back into the water reservoir, at some point the pump would run dry (possibly causing the decrease in pump noise). Once it ran dry, and if it weren't shut down by some electrical cutoff or manually, it would, at some point begin to withdraw water from the reservoir again (causing a return to the 'normal' pump noise). However, this does not occur.

I feel as if the focus of this thread has been diverted from the OP's original question. My apologizes to the OP. There are far more qualified people here to answer your questions than I. With that in mind, I will become an observer from here on out.

Post by **Endo** » Sun Jan 18, 2009 7:55 pm

zoey wrote:
I was thinking a little more about it, which usually means that I'll come up with an incorrect conclusion, but; lets say that the pump is happily pumping along. Water is freely flowing through the grouphead.

Then, all of a sudden, the water can no longer flow through the grouphead. At that point, from what I can determine by following water lines within the machine, water would follow the path of least resistance, which would be to the expansion valve (unless of course the pressure required to open the expansion valve is greater than what the pump can produce). From the expansion valve back to the T-connection, and because the pump is still pumping, back through the pump again.

That's correct. It's my understanding that the expansion valve opens to varying degrees every shot (unless the grind is so coarse that you never get 10 bar of resistance). Or in other words, a 10 second shot. The lack of sufficient pressure to extract and emulsify the coffee oils is why they taste so sour (and bad). Try it and you'll see your brew pressure won't go as high 10 bar. For most properly ground shots (20 seconds or more lets say), the pump pressure will be limited to 10 bar (your regulating valve setting) and your pump water supply will be split between the valve bypass and group head. Only the brew head water goes through flow meter so your shot volumes aren't affected.

zoey wrote:
This means that the pump would continue to pump unless there was some electrical cutoff mechanism in place.

That's right. That's what my machine does. The only thing that normally cuts it off is the volumetric flow meter hitting its preset limit. Since I get no flow during a backfush, it goes on forever. I was at least expecting a "no flow" alarm but since that never happens, I'm assuming they removed this function. There's one other thing that would cut off the flow and that's the vibe pump safety cutoff (to avoid pump burn-out). I've never hit this cutoff since I think it is a time limit of more than one minute.

zoey wrote:Having said that, it would also stand to reason that the noise from the pump would remain relatively the same. However, as evidenced by the video, it doesn't. In fact, the pump sound becomes quite dampened.

My pump sounds the same. Yours doesn't and your regulating valve appears to be set high (at 10 bar). So I'm thinking perhaps your pump is not strong enough to push past 10 bar and that is why you get the sound, the pump stall and the "no flow" fault. I think your solution might be to lower your pressure to 9 bar. Your espresso should taste better too. Perhaps your pump is weak or damaged. I think the Ulka 52 watt pump is rated up to 15 bar max so it should not be stalling at 10 bar.

zoey wrote: Just for the sake of hearing myself type, if the water were being diverted back into the water reservoir, at some point the pump would run dry (possibly causing the decrease in pump noise). Once it ran dry, and if it weren't shut down by some electrical cutoff or manually, it would, at some point begin to withdraw water from the reservoir again (causing a return to the 'normal' pump noise). However, this does not occur.

No. The pump won't run dry. The water simply goes back to the pump when the valve is opened (an endless loop).

zoey wrote:I feel as if the focus of this thread has been diverted from the OP's original question. My apologizes to the OP.

No need to appologize. You're right on topic.

I appreciate having another Mini owner to discuss things. Your machine is very interesting and has helped a lot to get to the bottom of this issue.

Post by **lessthanjoey** » Sun Jan 18, 2009 8:11 pm

For the record I also have a mini and I have *never* seen the lights come on (either during a choked shot or with the backflush disk in the single portafilter).

Post by **Endo** » Sun Jan 18, 2009 8:26 pm

lessthanjoey wrote:For the record I also have a mini and I have *never* seen the lights come on (either during a choked shot or with the backflush disk in the single portafilter).

Ahhhaa...the plot thickens...

Is yours a Mini Vivaldi or a Mini Vivaldi II? Is it relatively new (mid 2008) or one of the early ones (2007)? What's your brew pressure during backflush? Does your pump struggle during backflush or just stay the same (like my video)?

So many questions......

Post by **David23** » Mon Jan 19, 2009 8:53 am

Endo wrote:
lessthanjoey wrote:For the record I also have a mini and I have *never* seen the lights come on (either during a choked shot or with the backflush disk in the single portafilter).
Ahhhaa...the plot thickens...

Is yours a Mini Vivaldi or a Mini Vivaldi II? Is it relatively new (mid 2008) or one of the early ones (2007)? What's your brew pressure during backflush? Does your pump struggle during backflush or just stay the same (like my video)?

So many questions......

My Mini V II pump continues to run without struggling until I turn it off manually. I haven't noticed any change in the lights. I will pay closer attention today.

Post by **Endo** » Mon Jan 19, 2009 9:31 am

They're getting the same thing at Chris Coffee on their machines as well. Seems our Minis are acting like the rest (right or wrong). I'm still not sure what's up with Zoey's machine.

I may get some e-mails back today that will hopefully explain things.

Post by **lessthanjoey** » Mon Jan 19, 2009 7:15 pm

Endo wrote:
lessthanjoey wrote:For the record I also have a mini and I have *never* seen the lights come on (either during a choked shot or with the backflush disk in the single portafilter).
Ahhhaa...the plot thickens...

Is yours a Mini Vivaldi or a Mini Vivaldi II? Is it relatively new (mid 2008) or one of the early ones (2007)? What's your brew pressure during backflush? Does your pump struggle during backflush or just stay the same (like my video)?

So many questions......

I'm a hair above 9 bars during backflush with the disk. I bought my machine at the beginning of August '08 from Chris Coffee. I actually had a problem with my original pump about a month in and had it replaced (although strangely, the replacement was slightly higher wattage than the original - it was otherwise visually identical). The pump sounds identical whether I'm pulling a shot or backflushing. It is definitely *not* like Zoey's. I believe it's the same as yours Endo, but it's a little hard to judge in the video. The noise becomes quieter and less buzzy (?) as full pressure is reached, but it certainly doesn't stop. I also have progressive preinfusion if this might be a clue as to why I don't get a flow rate warning... (is it flow rate, or volume, or some combination?)

Post by **Endo** » Tue Jan 20, 2009 11:02 pm

I'm starting to get some feedback on this problem. Chris tells me my machine is normal. He tells me the water through the expansion valve flows back to the tank. He says since there is no total blocking like on the regular Vivaldi, there is no alarm.

This seems odd to me since this overpressure loop he describes does not bring flow past the flow meter. The only thing I can come up with is perhaps since the valve is open to the flow meter (but not actually flowing due to the blind basket), the flow meter is still registering a slight flow from the pulses of the vibe pump.

More investigation is required. I may need to strip the machine again follow the water lines again. Maybe the e-mail I sent to LaSpaziale will clear this up.

I'm still not sure what's up with Zoey's machine. My guess is still that his pump stalls more easily (perhaps an older 42 watt version), and since it's completely stopped, that's why he registers the "no flow" alarm on his machine 3 seconds later. Or the OPV is set too high (at 15 bar lets say) but his gauge is only showing 10 bar. This would stall the pump too. Or more likely, a combination of the two issues.

Anyway, one problem at a time.

Post by **lessthanjoey** » Tue Jan 20, 2009 11:19 pm

My volumetric dosing is also off (by at least 100%) between free running water and pulling a shot, but I had assumed that it was the progressive preinfusion. Now that I think a little bit harder about it though, I do get less volume to cutoff from a choked shot... Maybe a trial is in order (anything is easier than putting the covers back on!)

Post by **Endo** » Tue Jan 20, 2009 11:44 pm

lessthanjoey wrote:My volumetric dosing is also off (by at least 100%) between free running water and pulling a shot, but I had assumed that it was the progressive preinfusion. Now that I think a little bit harder about it though, I do get less volume to cutoff from a choked shot... Maybe a trial is in order (anything is easier than putting the covers back on!)

According to the flow diagram, the flow should not be affected since the OPV is before the flow meter. So any extra water just gets recirculated from the behind the pump (high pressure) to back in front of the pump (low pressure) at a tee fiting. Since the return pressure is now high pressure (but still cool), it should just flow back to the tank. I can't check this since there is no way to open the tank.

One other funny consequence of this is that if you have a flow restrictor ahead of the pump (like my Mk1 tank filter/softener), the added restriction should create a boost pressure for the pump making it work less hard (which may be why my pump seems so happy when backflushing).

Things are starting to make sense.

Post by **Endo** » Thu Jan 22, 2009 10:02 am

I think I got all the information I'm going to get on this subject from the Retailers and Manufacturer. Final answer is:

Mini Vivaldi DOES NOT show a fault alarm during normal backflush.

It seems if your pump stops (due to a very high OPV setting or a pump failure) or if your get a flow meter failure, you may still get the alarm. (Although I've only seen this in Zoey's YouTube video and have never recreated it on my machine).

So, that means you will have to backflush the Mini by running for 10 seconds and then stopping or by listening carefully (although the pump noise changes very little on my machine). This is the standrd method used on most other "non-electronic-alarm" machines (like the Silvia for example).

Hope that clears things up.

Chas, you may want to make changes to the CC owners manual to avoid poeple running their vibe pumps too long (waiting for the lights to change).

Post by **JohnB** » Thu Jan 22, 2009 11:25 am

Endo wrote:
So, that means you will have to backflush the Mini by running for 10 seconds and then stopping or by listening carefully (although the pump noise changes very little on my machine). This is the standrd method used on most other "non-electronic-alarm" machines (like the Silvia for example).

Or by watching the brew pressure gauge if you have a V2.

Post by **Endo** » Sat Jan 24, 2009 4:57 pm

Zoey, I'm curious to see if you have resolved your backflushing issues shown in your video.

The pump definitely seems to "stall" (there is no way it can get that quiet and still be pumping).

I suspect it is either the expansion valve set too high, the pump being too weak, or a combination of the two. Either way, if this is true, your shots may be affected (not just your backflushing).

You might be interested in this post where a similar issue happened on a vibe pump Anita:

http://www.home-barista.com/espresso-ma ... t7208.html

Post by **Endo** » Tue Feb 10, 2009 8:15 pm

Got a message back from LaSpaziale on the Mini backflushing alarm:

I submitted your request to my technician and he explained me as follows :

“ in MINI Vivaldi model, the flow meter failure alarm starts only when the control board doesn’t sense the impulses generated by the flow meter, that happens when the hall effect or the control board or the cabling are failed.

When the machines delivers water with the blind filter, the water doesn’t came out to the group but to the expansion valve, so after some seconds of delivery, the control board will signal the flow meter failure alarm.”

The technician suggests you to try the test again by simulating the flow meter failure, for example by disconnecting the cable, after some seconds of delivery, the machine will signal the flow meter failure alarm.

I think something must be lost in translation. Anybody want to guess what a "hall effect" is?

I'll stick by my theory number 1, that the flow meter is still seeing some small movement when the OPV is open and the vibe pump is running. I'll try disconnecting the flow meter as they recommend just to rule out theory number 2 (disabled in software).

Post by **JohnB** » Tue Feb 10, 2009 9:03 pm

Endo wrote: I think something must be lost in translation. Anybody want to guess what a "hall effect" is?

This should clear it up for you: http://en.wikipedia.org/wiki/Hall_effect