Adjusting extraction pressure?

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cnadon
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Joined: 16 years ago

#1: Post by cnadon »

I have have Gaggia TE heat exchange machine with a rotary pump. The extraction pressure seems to have been slowly creeping up on me and now stands at about 11.5. There's no service manual for this machine that I can find and I'm wondering how to adjust the pressure downward. Any help much appreciated.

Thanks.

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HB
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#2: Post by HB »

Turn the pump's bypass valve screw clockwise to increase pressure, counter-clockwise to reduce pressure.

Image
See screw labeled "pressure adjusting screw"

Keep in mind that a rotary pump adds to the inlet pressure; recommended inlet pressure is typically around 2 bar. If you find the pressure creeping up, it may be due to increasing inlet pressure caused by a failing pressure regulator for your home/business (around here, the street pressure is around 100 PSI and each home/business has a pressure regulator to reduce it to a more manageable ~55 PSI).

See Brew pressure regulation of plumbed-in espresso machine with rotary pump for more details.
Dan Kehn

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erics
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#3: Post by erics »

There's no service manual for this machine that I can find . . .
If you do a "Google search" on Gaggia TE, 1st-line has one and you may be able to convince them to photocopy the manual for a few $$.

In addition to what Dan said, another cause for "creeping up" brew pressure is a sticking by-pass valve in the pump. It is very easy to take apart BUT be sure to disconnect/shut-off your water supply first.
Skål,

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

cnadon (original poster)
Posts: 44
Joined: 16 years ago

#4: Post by cnadon (original poster) »

Dear Dan and Eric,

Well, ask and you shall receive. Thanks so much for the help and information. I backed the screw out quite a few turns on the relief valve and got the pressure down to 10. Quite an improvement in the shot. But I think you're also right about the failing pressure reducer (our local pressure is around 90) which I will try to replace this weekend.

Thanks also for the lead on the manual. The machine is now about 10 years old and starting to demand a little pampering.

Best, Chris