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Thread: Adjusting the OPV (over Pressure Valve) Gaggia Classic

  1. #1
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    Default Adjusting the OPV (Over Pressure Valve) Gaggia Classic

    OPV Adjustment for the Gaggia Classic

    1. You will need a pressure gauge that has been modified to fit the bottom of the standard domestic Gaggia portafilter. (fig a)



    This assembly cost me less than £10 to construct and the parts were readily available.

    2. Prime and warm up your machine to the normal operating temperature (At least 20 mins).

    3. Youíll notice that thereís no basket in the portafilter above, false pressure readings will be given if you leave it in there. Fill the pressure gauge with water from your machine before attaching it to the head. This serves to eliminate the chances of air being trap in the portafilter and primes your machine for the first test.

    4. Switch the pump on. As the pressure rises open the steam valve a little, this will hopefully allow any remaining air out of the system. Once you have a steady stream of water from the steam wand close it and allow the pressure to build until it settles.
    If youíve never adjusted your OPV before youíll probably looking at around 14 bar of pressure. These machines are shipped at this pressure for use with pods so if you do use pods donít touch a thing. Make a note of your reading and switch off the pump.

    5. SWITCH THE POWER OFF AT THE WALL AND REMOVE THE PLUG FOR ABSOLUTE PEACE OF MIND.

    6. Remove the two screws from the rear of the top plate and lift away. There is an earth wire attached to the cover, remove it but do not forget to replace it on reassembly.

    7. Itís hot in there, be careful. Part of the reason for having the machine warm is that it comes apart a lot easier. Locate the OPV (fig b)



    (fig b) OPV valve

    Remove the pipe and put it to one side out of the way. (fig c)[/CENTER]



    (fig c) OPV pipe removed

    Using a ratchet wrench, extension and 17mm head remove the top of the OPV. I have specified the tool because I have read of people attempting this with spanners or adjustable spanner even pliers. This is a really bad idea. Like I said itís hot and you will inevitable burn yourself. At best a spanner will slip and you may damage something else such as your solenoid.

    Once the top of the OPV is removed you will see a small 5mm (3/16) hex head inside. It can be difficult to see sometimes as there will be water on top of it, but trust me itís there. (fig d 1 and 2)



    (fig d 1) OPV, 5 mm hex head revealed

    Insert a 5mm (3/16) Allen key in the hole and turn it anti clockwise approximately 270į or three quarters of a turn. Reassemble your machine in reverse order. Donít forget that earth wire and re test the pressure.

    8. This is known as a static pressure test which means thereís no flow through the portafilter. The pressure you should be aiming for is 10 bar not 9 bar. This is because the difference between a static reading of 9 bar and a dynamic reading i.e. with flow through the head is 1 bar less. Therefore you need to set your machines to 10 bar which will give you 9 bar dynamic.

    Here's a video of the gauge in action (at this point it's reading 9 bar instead of 10 bar) http://flic.kr/p/9LQDDk

    9. You will need to repeat this a few times to get it right but itís worth it IMHO. I am pulling vastly improved shots with much better crema.

    Disclaimer: I can not be held responsible for any damage that may invalidate any warranty. You should only attempt this adjustment if you know what you are doing and have the right tools to do it. If you do not feel in any way confident then leave it alone.
    Last edited by AndyL; 03-11-12 at 08:00.

  2. #2
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    Nice work Andy!
    Just one thing....
    Last edited by AndyL; 1 Minute Ago at 05:07. Reason: grammer
    You may need to edit once more.... Reason: spelling

  3. #3
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    I take my hat off to you Sir.

    Pictures are great and the write-up is spot on.
    Gaggia Classic / Porlex Grinder

  4. #4
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    Thank you James.


    Sent from my iPhone using Tapatalk
    Gaggia Selecta Coffee Delux (Rancilio Silvia steam wand mod, OPV and steam valve mod) : Iberital MC2 : Happy Donkey Tamper : Gaggia Bottomless Portafilter :

    Favourite coffee/roast is currently BSCA#1 Brazilian Speciality Coffee Association number 1 blend from Two Day Coffee Roasters Bristol
    :

  5. #5
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    Andy - how many times did you have to repeat this proceedure to get the magic 10 bar (9 actual) : -

    ''Insert a 5mm (3/16) Allen key in the hole and turn it anti clockwise approximately 270į or three quarters of a turn. Reassemble your machine in reverse order. Donít forget that earth wire and re test the pressure''


    Cheers
    @garydyke1
    Tasting the rainbow

  6. #6
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    I did the OPV mod using the blind basket method a few months ago, and it took about four adjustments before I found the spot.

  7. #7
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    The first 270 degree turn will get you close most likey. From there you have to use your judgement and make small adjustments most probably. It's the luck of the draw, you just keep going until you hit it. I think it took me 3 attempts to get it right in the end.

    It may seem a lot of fussing about but once it's done it's done. You won't need to do it again.


    Sent from my iPhone using Tapatalk
    Gaggia Selecta Coffee Delux (Rancilio Silvia steam wand mod, OPV and steam valve mod) : Iberital MC2 : Happy Donkey Tamper : Gaggia Bottomless Portafilter :

    Favourite coffee/roast is currently BSCA#1 Brazilian Speciality Coffee Association number 1 blend from Two Day Coffee Roasters Bristol
    :

  8. #8
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    Well A big thanks to Andy for firstly lending me his pressure gauge and secondly not call screening me fathers day lol

    When i first ran the gauge it went straight off the gauge! Rang Andy really worried lol Got it sorted after firstly gulp..... adusting it the wrong way (my wife and daughter both felt the need to talk during this stage!) anyway I think 3 adjustments are needed and the hardest part was getting the earth clip off!

    Anyway just another little thing on the classic theres 3 tabs at the front of the top you need the middle tab showing (When the tops on) and give the water funnel a little push to get the cover back on correctly.

    Ive spoken to Andy and hes kindly offered to pass his gauge around and the borrower just pays the last sender the postage fee Recorded is £5.85

    So shall we start a little list of who would like to borrow it?

    1) AndyL
    2) PaulN
    3)
    4)
    5)
    6)
    Last edited by PaulN; 21-06-11 at 11:23.

  9. #9
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    Makes great sense!
    I'll go next please. Will PM you my details.
    Thanks chaps.
    Who's after me then?

  10. #10
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    1) AndyL
    2) PaulN
    3) MikeHag
    4)
    5)
    6)

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