Fluctuating manometer needle Problem

[Aracel]

My Mini's manometer needle fluctuates from 0 bar to 9.2 bar. It stops at 9.2 bar for about 5 seconds and go back to 2 bar, stops at 2 bar for about 3 seconds and go back to 4 bar, stops for a few seconds and go to about 9.2 bar. Stays at 9.2 bar for about 3 to 4 seconds and go to .5 bar. This process takes place within approximately 4 to 5 minutes. I think, this happens all day. I cannot stand all the time in front of the Mini to watch it; but everytime, I come near the Mini, I see that it is on 4 bar or 3 and fluctuates. When I am about to grind the beans, it is on 2 bar. When I do the hot flush, it goes to .5 (between 1 and 0 bar). When I'm ready to put the portafilter back, the manometer is on 2 bar. I have to hot flush for 1 second to make it stay at 0 bar. The shot comes very loose at the beginning. After about 4 seconds, it starts to get thinner and lighter but not as tight. When it becomes lighter, it takes about 30 seconds to fill the 2 oz. Does anybody experience a fluctuating manometer needle? I would appreciate it if anyone could give me some comments on this. Thank you very much in advance.

[chas]

There's a thread from a few folks with Mini's whose needles vibrate while the pump is running. You can find it using the Search function. However, it sounds like you are describing something very different which doesn't sound right at all. It sounds like a call to Chris Coffee Tech support is in order, assuming that's where you bought it.

[Cliff]

I will watch mine a little closer. I just noticed this morning that mine was doing the same thing. I will watch it tomorrow morning and post back.

[Aracel]

I will watch mine a little closer. I just noticed this morning that mine was doing the same thing. I will watch it tomorrow morning and post back

.

Thanks for the info. Please update me of your observation on your machine. By the way, how's the shot? Does it come out loose at the very beginning and gets tighter? Thanks again and hope to hear from you.

[chas]

It is curious that the manometer is doing this when the machine is idle. On the other hand, I'm not sure how much it matters just so long as you are getting a steady 9bar - or whatever you set it at - when the pump is running.

After spending all that money on the V2 Mini the last thing you probably want to do is spend more money. However, you might consider getting a portafilter pressure gauge. That way you could see if the PF gauge was exhibiting the same behavior or if it is just the built-in manometer.

http://www.chriscoffee.com/products/hom ... fwithgauge

Alternately, you can buy a PF Pressure Gauge Kit from Espresso Parts for half the price and attach it to an existing portafilter.

http://www.espressoparts.com/product/V_ ... e_Kit.html

[Cliff]

Sorry I have not posted back soon but I have been waiting for my machine to reproduce the same actions as before and it has not. I was trying to think if I had done anything different and the only thing that I could come up with is it was the first time that I had turned my machine completely off and back on again. I don't see how it could of but maybe some air got into the system some how. Again I have know clue and don't know if air in the line would even do this as I am just now exploring this machine. Its just a quick thought.

[zoey]

My Mini does the same thing. Just not as frequently as yours (or at least I think so). It's at zero bar right now. 30 minutes ago I noticed it was at 4 bar.

I've spoke to the techs at Chris's and they said it's nothing to worry about whatsoever. I was letting off the pressure by pressing a shot button. Chris's said don't bother. No harm will occur except to the shot button from overuse.

[Aracel]

My Mini does the same thing. Just not as frequently as yours (or at least I think so). It's at zero bar right now. 30 minutes ago I noticed it was at 4 bar.

Thanks for your kindness to observe your machine. By the way, when you pull a shot, does it come out loose at the beginning and then turn tighter? When you start to pull a shot, is the needle on zero bar or somewhere else between 2 and 4? Hope to hear from you. Thanks so much.

[Cliff]

When I pull my shots it starts at 0. Like I said I just happened to see the needle fluctuating the other day and it has not happened again, but I did not have a lot of time this weekend. Now for your question on is the shot loose at the beginning I would say no but would need to see a video of what your talking about I guess. Do you have the ability to shoot a video?

[Aracel]

When I pull my shots it starts at 0. Like I said I just happened to see the needle fluctuating the other day and it has not happened again, but I did not have a lot of time this weekend. Now for your question on is the shot loose at the beginning I would say no but would need to see a video of what your talking about I guess. Do you have the ability to shoot a video?
When I pull my shots it starts at 0. Like I said I just happened to see the needle fluctuating the other day and it has not happened again, but I did not have a lot of time this weekend. Now for your question on is the shot loose at the beginning I would say no but would need to see a video of what your talking about I guess. Do you have the ability to shoot a video?

I posted a video in mutiply.com and sent it to ChrisCoffee. But I think it does not work because I sent a copy to myself and does not work. I will try posting it on youtube but I have to sign in first and will let you know. Thanks.

[Aracel]

When I pull my shots it starts at 0. Like I said I just happened to see the needle fluctuating the other day and it has not happened again, but I did not have a lot of time this weekend. Now for your question on is the shot loose at the beginning I would say no but would need to see a video of what your talking about I guess. Do you have the ability to shoot a video?

I posted a video in mutiply.com and sent it to ChrisCoffee. But I think it does not work because I sent a copy to myself and does not work. I will try posting it on youtube but I have to sign in first and will let you know. Thanks

Hello Cliff, I could not get the valid username at Youtube. It took me half an hour or so changing the username and no luck. By the way ChrisCoffee was able to view the video I posted at multiply.com. If you don't mind giving me your email address, I could send you a copy. Thanks.

[Cliff]

I just sent you a PM

[zoey]

If you would like a comparison opinion, you can shoot me the link as well. PM sent.

I guess I'm not sure what you mean by 'loose'? Typically, the pressure starts at zero, unless of course the needle is magically floating somewhere between 0 and 9bar. After the shot starts it cruises up to about 8.5 bar, which is what I've adjusted to machine to run at.

After the shot is pulled, the needle sits anywhere between 0 and 9 bar. It actually floats around all day long. Again, Chris's Coffee told me that it's no big deal.

[chas]

Below is a diagram of the water flow in the V2. The Mini should be almost identical except for the type of pump and having a reservoir instead of a direct water connection.

As you can see the group pressure gauge actually sits right at the output of the pump. This is why the V2 shows input water line pressure when the pump is not running. In the case of the Mini there is no pressure coming into the connection from the pump. However, I believe that the T connector prevents water from flowing back toward the pump which also keeps the group pressure gauge from just dropping to zero bar and staying there between shots. The solenoid valve on the boiler is closed so boiler pressure can't get back and register on the group pressure gauge. Sonsequently, it looks like group boiler pressure may bleed back into the line connected to the group pressure guage resulting in a reading that bounces around.

As an electrical engineer I can make best sense of it by mentally thinking of it as a high impedance input circuit. In the V2 there is always pressure akin to a constant voltage which you would read on a voltmeter. In the case of the Mini, it's like a floating input with no driven voltage. A voltmeter applied to such a circuit will tend to continually drift.

[zoey]

Maybe this diagram will help you come to a conclusion? Looking at the diagram, I don't understand why there would be any pressure at the gauge if the boiler is turned off (economy mode)? According to the diagram, as I understand it, the gauge is located at the boiler.

Sorry, I know it's a bad scan.

And BTW~ the new software running this site is still making me resize photos

The image must be at least 0 pixels wide, 0 pixels high and at most 1024 pixels wide and 1024 pixels high. The submitted image is 1057 pixels wide and 1423 pixels high.