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Permalink Reply by Mike Sabol on August 18, 2012 at 10:43pm

Hey William there is a lot of ground to cover between "blinking lights" and "replace flow meters"  That's a little like "toe hurts", "must amputate".

 

The first thing I'd do is to pull a water shot and see if the lights blink.  The lights start to blink when the computer thinks it should have read more "clicks" from the flowmeters than it has in a certain amount of time, which indicates impeaded water flow.  But that water flow can be impeaded at several different places and not just the flow meters.  If you can pull a water shot without the flowmeters blinking then the problem is somewhere else.  The first place I'd look is the water filter on the wall upstream of the machine.  If you don't have a water filter for the espresso machine you could easily be looking at much more than just replaceing the flow meters.  Also, if someone has accidentally put the machine into "program mode" and wiped all the volume programs out of the CPU, the lights will blink while you're pulling a shot.  You can check this by putting the machine into program mode yourself and programming a couple of the buttons and seeing if the programming holds.  Another thing about scale in the flow meter is that it will impeade a "continuous flow" shot just like it will a "volumetric shot" so if the espresso pulls well and at an appropriate time then scale in the flow meter is not your issue.  If you can describe your symptoms in as much detail as you can I might be able to help you track down the problem.

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Permalink Reply by William Chun on August 18, 2012 at 11:56pm

Thank you for the reply mike!

Free flow water is no problem. Its not blinking at all and also installed everpure water filter ESO7. tested programming mode and no problem.

Okay, here is my symptoms: 1group, almost blinking every time when i pulling a 25~30 seconds shots. working alright with the 20~23seconds shots. I am having most of problems with this group head. 2group head, blinking when pulling 30~35seconds over extraction shots. not bad at all. But need to replace flowmeter too. 3group head, This one working perfect having no problem pulling shots even over extracted. 

So in my point of view is most likely problem with flowmeter error......? 

Do you know how to replacing the flowmeters when machine is on? I need to turn off and depressurize machine or cool it down? or I can just off the machine and unscrew bolts and replace it?  I have no idea replacing flowmeters :(

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Permalink Reply by Jay Caragay on August 19, 2012 at 7:29am

Sounds to me like there's "too much coffee" in the portafilters that impede the flow causing the blinking lights - especially since you say the lights do not blink with free flow water. Maybe use a coarser grind?

Swapping out the flowmeters is relatively simple. Get the new ones first!  Then shut off the power and cool down the machine (unless you don't mind being scalded with 200F water).

Once the machine has cooled (and you've turned off the water supply valve - wherever that may be located because it is external of the machine), then simply use open-ended wrenches to loosen the nuts and pull the flowmeter, remembering to also remove the wiring.

To install, simply reverse the procedure and you should be back to work.

Good luck.

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Permalink Reply by Mike Sabol on August 19, 2012 at 7:38am

William, have you tried reprogramming the two group heads you're talking about? The lights blink because the computer thinks it should be seeing more ticks from the flow meter but the flow meter isn't always the source of the restriction. It's very possible to re

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Permalink Reply by Mike Sabol on August 19, 2012 at 7:46am

Replace the meters and still end up with the same problem. Coffee can work it's way back into the banjo tube and impead things or perhaps the two heads in question just need a super duper back flush. You can also turn the machine off, turn off the water, and then take the top odd the meters and look for any scale inside them. Just be sure to unplug the machine and have a towel handy, as you'll get some water leaking when you take the tops off the meters.

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Permalink Reply by Brady on August 19, 2012 at 6:29pm

Hi William.

If the group shuts off after dispensing the amount of coffee that you've told it to dispense, your flowmeters are working. Do not replace them.

What is your total shot volume? If you are pulling very slow, short ristrettos I wouldn't be surprised to see your lights flash.

If you feel that water-only flow rate is too slow, investigate for obstruction and clear it out wherever you find it.

On the other hand, if you're really itching to drop $235 + shipping for no apparent reason, I can think of better places to spend it. For example, that would cover some nice cigars and bottles of liquor for Mike, Jay, and I :).

Hope that helps.

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Permalink Reply by Scott on August 20, 2012 at 7:37am

Hi William, what do you store on top of your machine?  The flowmeter caps (the sensor) are susceptible to failure from sugary stuff getting split on them. And they are right there under the cup tray.  Or if there is corrosion on the leads.  Inspect and gently take a wire brush to them if need be.  You can replace just the flowmeter impellers and caps, and not have to deal with smallish pipes.  

Can I get in on the cigars and liquor too?  That stuffs getting expensive up here in Wash State.   

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Permalink Reply by Eric Schaefer on August 21, 2012 at 7:00am

I'd just like to second what Brady said about ristrettos.  My old shop in St. Louis pulled nothing but 1.5oz double-ristrettos, aiming for 30 seconds.  Tasted amazing that way, but flowmeters would mis-read and cause keypads to blink at least 50% of the time. 

We rebuilt our 3 group Linea AV into an EE model (no flowmeters, just manual brew switches.)  We left our 4 group as an AV because it had the cronos built-in shot timers, which we liked, but still ran it as a manual machine with integrated shot timers. 

So, if that's the kind of shots you pull, I'd recommend ignoring the flowmeters and enjoying your ristrettos!  If you're not pulling slow, short shots, the rest of what you need to check is pretty well covered in the comments above.

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