I noticed this afternoon when doing a cooling flush, that my machine didn't seem to be putting as much pressure out and the stream didn't come together at first. It doesn't seem as loud lately either, which I wasn't complaining about until I noticed this odd behavior flushing.

I put my blank disk in and did a water backflush with no major debris and the pressure did get up to 9+ bar, but I'm wondering if this is potentially indicative of anything? A crimped tube, pump issue, group scale (I haven't opened up the mushroom yet since owning the machine but I don't use tap water) etc?

A bump to see if anyone can comment? I double checked my OPV and it's a little low but I haven't adjusted it at all. I cleaned the basket last night but the water during a flush isn't coming together to a stream like it used to.

I know it is a bit vague, but something definitely does not seem right. I would dig deeper with opening the machine, only if you are mechanically inclined to see what's going on under the hood. I used to own an E61 and never ran into that problem.

Knowing what the machine is and what the maintenance schedule has been would be helpful. Pump pressure reading will depend on the "load", input source, and type of pump, as well as where the reading is being taken from. If the complaint is lack of water flowing from the shower screen, has it and the dispersion plate ever been removed and cleaned? Various clogs in the system can also have an effect.

Lots of info out there, so some research is in order.

A vibe pump can begin failing by getting quieter and not producing full pressure during a shot. This happened to me last year when I had to replace my vibe pump. Here you can see it would only make about 7BAR.
I've also read that it can still make 9BAR against a backflush disk since there is no flow, but that wasn't my experience.

Assume you're talking about your Vibiemme QM machine here.

At the top of the mushroom you have a small jet (gicleur) that is there to restrict flow. Any scale or debris there may overly restrict and you would see a lower rate of flow when flushing. In the same area there is also a cylindrical screen, and four small holes in the mushroom that might be clogged with scale. If you have clogging here, the pump pressure gauge while flushing might go higher than it would when everything is clean. (More info from Randy Glass' how-to is available here: Overhauling and Lubricating the E-61 Group )


Another possibility is that the dispersion screen (aka shower screen) is clogged with coffee residue. It's generally a good idea to remove that screen periodically and clean it. If it's so clogged that it is restricting flow, then it should also be giving you some foul tasting shots. Randy also has a nice page on that: How to Remove an E-61 Shower Screen and Brewhead Gasket

cuppajoe wrote:Knowing what the machine is and what the maintenance schedule has been would be helpful. Pump pressure reading will depend on the "load", input source, and type of pump, as well as where the reading is being taken from. If the complaint is lack of water flowing from the shower screen, has it and the dispersion plate ever been removed and cleaned? Various clogs in the system can also have an effect.

Lots of info out there, so some research is in order.

Ah, it is in my profile on the right bar but that isn't visible for mobile. I have a QM Andreja Premium, purchased April 2015.
I use a combination of RO + filtered tap water, and tried cleaning the basket - but did not remove the dispersion screw. I will try that next. I can open it up and see what's going on there, but short of finding a leak or a crimp I wouldn't be sure what to look for.

. . . I wouldn't be sure what to look for.

When you simply flush water with an empty portafilter with or without basket, the brew pressure gage should read somewhere between 3 and 4 bar and the flowrate should be between 450 and 500 ml/minute. This pressure reading is a result of the restrictions in the hydraulic path, the great majority of which is caused by the installed 0.70 mm gicleur.

erics wrote:When you simply flush water with an empty portafilter with or without basket, the brew pressure gage should read somewhere between 3 and 4 bar and the flowrate should be between 450 and 500 ml/minute. This pressure reading is a result of the restrictions in the hydraulic path, the great majority of which is caused by the installed 0.70 mm gicleur.

I checked this morning and it was barely at 2 bar when not under pressure. My shot still got up to 8.5 bar and the blind basket still yields about 9 bar. I'm not sure if I should be calling CCS or just continue to use it since under load it seems okay.

homeburrero wrote: At the top of the mushroom you have a small jet (gicleur) that is there to restrict flow. Any scale or debris there may overly restrict and you would see a lower rate of flow when flushing. In the same area there is also a cylindrical screen, and four small holes in the mushroom that might be clogged with scale. If you have clogging here, the pump pressure gauge while flushing might go higher than it would when everything is clean. (More info from Randy Glass' how-to is available here: Overhauling and Lubricating the E-61 Group )

Another possibility is that the dispersion screen (aka shower screen) is clogged with coffee residue. It's generally a good idea to remove that screen periodically and clean it. If it's so clogged that it is restricting flow, then it should also be giving you some foul tasting shots. Randy also has a nice page on that: How to Remove an E-61 Shower Screen and Brewhead Gasket

I did recently clean the screen (soaked in Cafiza), but I couldn't get the dispersion screw out without hurting the brass as I only have metal pry tools. I will work on that next, and at just under a year it's probably a good time to check the mushroom and gicleur for scale build up.