How to adjust brew pressure of rotary pump espresso machine?

Need help with equipment usage or want to share your latest discovery?
Thatchmo

#1: Post by Thatchmo »

Hey, since it's the weekend and everyone at Chris' Coffee is not around....Does anyone know how to adjust the brew pressure on the Duetto? It's currently at 8.5 and I wanted to goose it up to 9...

I've taken mine apart to replace/upgrade the PID, so I am familiar with the insides....So if it's an easy fix, could someone let me know?

Thanks,

Kirk

User avatar
HB
Admin

#2: Post by HB »

Assuming it's like Procon rotary pumps, you should find a pressure adjusting screw similar to the one shown below:

Image
From Procon exploded view; also see Adjusting espresso machine's rotary pump brew pressure?

Counter-clockwise = more water passes from outlet to inlet through the bypass valve = lower pressure. Clockwise = less water passes from outlet to inlet = higher pressure. Also keep in mind that your inlet pressure should be regulated to ~25 PSI.
Dan Kehn

thaxton

#3: Post by thaxton »

are you sure your pressure shown in the gauge is not correct? Provided the taste and appearance of espresso is appropriate, I wouldn't change the pressure. If it is not, search the Overpressure Valve adjacent to the pump. But still I doubt default factory adjustment is wrong.

akallio

#4: Post by akallio » replying to thaxton »

Duetto is a rotary machine, so you do not adjust OPV but pump directly. Typically the internal gauge shows too high pressure. I don't know if the mentioned 8.5 bars if from grouphead or internal gauge, but it is low-ish anyway.

User avatar
Sebastiaan007

#5: Post by Sebastiaan007 »

All of the Duetto's I have tested are put on 9.0 bar on the coffee, 0.5 Bar for the OPV with container and with water mains 1.0 Bar.

So if you have it plumbed in and it says 10 Bar you should have 9 Bar on the coffee
I barista, do you?

Thatchmo

#6: Post by Thatchmo »

Thanks for all the responses folks,

Well, it's NOT plumbed in....and it is reading 8.5 on the internal gauge...I don't have the means to measure at the grouphead....this how it reads both with a blank inserted and a fully loaded portafilter...So, I wanted to adjust it to at least read 9, especially if it drops a bit going to the group head...My pulls lately have been a bit bland and flat...and the temp on the PID's set at 200, so I thought I would up the pressure a bit and see if that helps....



Kirk

akallio

#7: Post by akallio »

Well, it's NOT plumbed in....and it is reading 8.5 on the internal gauge...I don't have the means to measure at the grouphead....this how it reads both with a blank inserted and a fully loaded portafilter...So, I wanted to adjust it to at least read 9, especially if it drops a bit going to the group head...My pulls lately have been a bit bland and flat...and the temp on the PID's set at 200, so I thought I would up the pressure a bit and see if that helps....
Seems fair enough, I would also up the pressure a bit.

Btw. I can check the offset in pressure readings between internal gauge and portafiler gauge on my Duetto, if you wish.

Jeepin' Geo

#8: Post by Jeepin' Geo »

Kirk,

I'm not plumbed in (yet), drawing from an external jug. 9bar set on the internal gauge gives me exactly 9 bar on a blind PF gauge.

George

Image

akallio

#9: Post by akallio »

I hope the original poster got the pressure tuned right. When you take out the machine case it is very easy to spot the adjustment screw. Actually there seems to be hole in the inner case for making adjustments, but as the outer case does not have a matching hole it is of no use...

Strangely enough, my machine shows 1 bar more on the internal gauge compared to PF gauge.

Thatchmo

#10: Post by Thatchmo »

Thanks for the tips and advice every one, I adjusted it one half turn clockwise, which bumped up the pressure .5 bar to 9.

I wondered about putting a hole through the case to make it easily accessible from the outside, but figured that it's not an adjustment I would need to do often and the 5 screws and two bolts don't take that long to deal with to take the case off....

Onward and upward!

Kirk