Adjusting the brew pressure on an Andreja Premium

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stevescapin

#1: Post by stevescapin »

I am facing a problem. I have read and followed the instructions of Chris' website in order to adjust the brew pressure. In order to get the pressure from 11-12 to 10, I have to turn the bolt to the extent that the tube connected to it becomes significantly twisted. I cannot imagine reaching 9 without rupturing the tube. What should I do? Should I remove the tube? If so, do I need to get a new one or can I reinstall the same? Advice is appreciated!

mgrayson
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#2: Post by mgrayson »

I did the same thing, and while I can't recall any tube twisting problems, I think I may put the pressure back up. I believe that the pressure at the portafilter is about 1 bar less than what is shown on the gauge.

I also get a resonance shriek whenever I backflush or have a very tight shot ever since I lowered the pressure.

Best,

Matt

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HB
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#3: Post by HB »

No problem-o.

It's just a silicone tube on a barbed fitting, not unlike the pump connections for an aquarium. You can untwist the tubing as you go, or pop it off and put it back on. Perhaps needless to say, remember to unplug the machine before getting your hands anywhere near the interior. If water drips into the casing, allow plenty of time for it to air dry before plugging the machine back in.

For those reading along, here's a really nice picture of the expansion valve / OPV for the Andreja Premium from http://www.chriscoffee.com/faq: Andreja Premium & Anita: Adjust brew pressure. The tubing is shown below the adjustment nut:

Image
(image courtesy of Chris' Coffee Service)
Dan Kehn

stevescapin (original poster)

#4: Post by stevescapin (original poster) »

Thanks for the info. Best customer service in town ;-) While I have your attention, I know that I am supposed to unplug the machine while adjusting the brew pressure. But there is no problem testing the adjustment (i.e. replugging) without reinstalling the cover...right? Finally, how much water should normally trickle in the drip pan when pulling a shot? I notice that a fair amount of water ends up there everytime I make a shot. Normal?

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HB
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#5: Post by HB »

stevescapin wrote:But there is no problem testing the adjustment (i.e. replugging) without reinstalling the cover...right?
First allow me to point out...
DISCLAIMER wrote:THIS ADJUSTMENT HAS BEEN DESCRIBED FOR INFORMATIONAL PURPOSES ONLY, BECAUSE ESPRESSO HOBBYISTS HAVE EXPRESSED AN INTEREST IN IT. THIS ADJUSTMENT SHOULD ONLY BE CARRIED OUT BY QUALIFIED REPAIR TECHNICIANS. SUCH ADJUSTMENTS REQUIRE MANIPULATING AND/OR BEING IN CLOSE PROXIMITY TO CONTROLS AND CONDUITS FOR ELECTRICITY, VERY HOT WATER, STEAM AND HIGH WATER PRESSURE. THE RISKS OF FAILING TO FOLLOW PROPER SAFETY GUIDELINES AND PROCEDURES INCLUDE SERIOUS INJURY OR DEATH AND THE DESTRUCTION OF PROPERTY BY FIRE AND OTHER CAUSES. THE AUTHOR ACCEPTS NO RESPONSIBILITY FOR ANY INJURIES OR LOSSES RESULTING FROM ANY ATTEMPT TO PERFORM THESE ADJUSTMENTS.
Now, what was the question? :wink:
stevescapin wrote:Finally, how much water should normally trickle in the drip pan when pulling a shot? I notice that a fair amount of water ends up there everytime I make a shot. Normal?
Yes, that's normal. Jim Schulman's Adjusting vibe pump pressure on HX machines explains the mechanics, including the diagram below:


(reproduced with permission)

With a blind filter, all of the pump water exits via the OPV. During a shot, a portion of the water exits through the OPV and a portion exits through the grouphead; Eric explains in more detail in Purpose of adjusting the OPV.
Dan Kehn

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erics
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#6: Post by erics »

stevescapin wrote:But there is no problem testing the adjustment (i.e. replugging) without reinstalling the cover...right? Finally, how much water should normally trickle in the drip pan when pulling a shot? I notice that a fair amount of water ends up there everytime I make a shot. Normal?
I can't imagine ANY water getting into the drip pan DURING the course of a shot other than, MAYBE, ONE stray drip from the lower exhaust port of the group assembly. When you complete the shot, certainly a portion of the group's brew water gets evacuated into the drip tray via this exhaust port. Water should flow from the OPV during the course of a shot and that goes back to the tank - maybe an ounce or so.

A way to handle the PITA silicone hose that is a "less than right" fit on the OPV outlet is to remove it and then reinstall it with a slight reverse twist to take into account the adjustment you will make - probably "1-1/2 to 2 flats" on the hex. Sometimes you can get lucky and twist the hose with your fingers while it is still on the outlet as Dan suggested. I would shoot for 9.0 bar with the blind basket and that should give you a little less during the course of a shot - maybe 8.6-8.7.

The reason the hose is "less than right" is that the next size up hose would be too loose and you're in the vicinity of that "not so inexpensive" Gicar control box.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

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HB
Admin

#7: Post by HB »

erics wrote:I can't imagine ANY water getting into the drip pan DURING the course of a shot other than, MAYBE, ONE stray drip from the lower exhaust port of the group assembly. When you complete the shot, certainly a portion of the group's brew water gets evacuated into the drip tray via this exhaust port. Water should flow from the OPV during the course of a shot and that goes back to the tank - maybe an ounce or so.
Sorry for the confusion, I assumed he owned the direct connect Andreja Premium. In that case, the OPV overflow is redirected to the driptray, otherwise, as you correctly pointed out, the pourover models redirect to the tank.
Dan Kehn

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erics
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#8: Post by erics »

And I, of course, didn't even think of a direct connect but just ASSUMED da normal AP. :oops:

I'll also let you know what they do about the "self-priming valve" that's screwed into the Ulka pump next week unless you already know.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

stevescapin (original poster)

#9: Post by stevescapin (original poster) »

My AP is direct connect. From what I understand, it is therefore normal that some water trickles in the pan during the shot. Thank you very much for all the information.