My OPV adjustment journey.

When I say ‘My OPV adjustment journey’, I do mean MINE !!!

Steve has got really really busy working on a secret squirrel project and I was getting sick of sink shots and crappy tasting coffee, as much as he seemed to think it tasted ok.

Soooooo I got home from work today and thought stuff it, I can adjust the OPV myself.


OK so here we go for the journey of how to adjust the BES900 OPV.

A good idea is to get hold of a Sunbeam Dual Filter, these consistently correctly show whether or not the gauges are working correctly, this works on a lot of machines, before I returned the EM6910 I was able to test the gauge on the BES900.ย  It came out at 9 bar, so concluding that the gauge IS working correctly.

The first step is to test the OPV pressure with a blind filter.ย  These filters are available from all sorts of places from coffee accessories online stores to the best roasters in Australia ๐Ÿ˜€ย  Thanks Jeff (mycuppa).

Mine tested between 12.5 to 13 bar.

First undo the screws.

I found that it was easier to start with the two screws on either side of the group head, these are just philips head screws, they hold the top panel in place.

The next two are on the corners of the back panel that says Breville.ย  These screws are Torx head screws, make sure you have the right screw driver so you don’t destroy the head and no we have the correct tools so we didn’t damage anything.

This allows you to pull the top panel away from the back panel.ย  Before you do this take the water tank out, when you do this you will see two screws at the top of the open space and the bottom right of the Breville panel that you just took the last two screws out of.

These screws are again just philips head screws.ย  Please take note that there is a long and short one, the long one goes into the left hand hole.ย  Once taken out you can now take the top panel off, lifting the top panel to allow for that to happen.

The back panel can be placed on the bench top without stretching or breaking the wire, well I found I could do that.

In the above photo you can now see the white plastic OPV sitting at the top left.ย  Below is a closer view.

Again make sure that the machine is switched off and unplugged.

I have had a fellow coffee enthusiast use this guide (see the comment) and they suggested a few additional instructions which I will add here.

The first thing you need to do is slide the silver hose clamp, use a pair of pliers to squeeze the clamp together which enlarges the clamp circle around the hose and you can slide it down the hose away from the OPV.ย  Next you need to take the hose off the OPV.

If the hose is really tight (mine was) you can use pliers right up near the fitting (as close to the cog as you can get) and wiggle the tube back and forth. That will help expand the opening and make it easier to remove.

What you will see now is a clip that sits over the adjustment cog.ย  You need to remove this, it has raised sections that keep the clip on where the square sections are, see below photo without the clip showing the raised sections, this can be a little difficult but just be careful and it comes off easily.

If you canโ€™t unclip the clip around the OPV cog, you can gently rotate the entire T-joint clockwise towards you. Then you can reach both sides of the clip more easily.

You’ll also notice in the above photo that there are lines drawn on the adjustment cog and the main section of the OPV.ย  These I assume are done during production.

As you’ve seen in the first photo this setting gave me the 13 bar pressure.

Due to not being able to move this cog by hand (fingers) I couldn’t tell which way was tighter than the other.ย  I tried going clockwise first, I went one full turn, I tested with the blind and the pressure was off the dial.

Oh one thing I should add here is, remember to put the hose back onto the OPV when you are testing it otherwise you end up with water everywhere and that can be a dangerous thing.ย  The other thing is be careful with your fingers when pulling the hose on and off, boilers are hot and can burn, and yes I am a clutz and have a blister!

I put it back to the original position and tried the other way.ย  I went one full turn anti clockwise.ย  The blind tested at 11 bar.

11 bar I still feel is too high, general consensus is that once you run a shot with coffee the pressure will come down.ย  I then did another adjustment to one and a quarter turns anti clockwise.ย  Hopefully you can see on the below photo the line on the adjustment cog sitting half way between top and bottom.ย  It is the bottom dark line, not the dirty marks from the pliers at the top.

This adjustment resulted at a reading of 10.5 bar, which at present I feel is where I want it to be.

Now it’s time to put everything back together, just do the opposite of what you did to take it all apart.

Do be careful putting the back panel back on as the wires are a little messy and they can get caught in places you don’t want them and if you force it you could damage them, if you get one caught and pinch through the insulation you could make external parts live which could be deadly, take it easy and it will all just slot together.

My next step was to do another blind test, this time it came in at 10 bar, honestly I have no idea why it changes but I can only think it has to do with everything sealing correctly once the hose and clips are all put back on.

The above turned out to be completely fine.ย  I was ready to try an actual shot.

I am using my Spong No.1 to grind.ย  I measure out 20 grams of 16 day old beans, this particular blend is best from 12 days so 16 days is perfectly ok, grind and pack into the portafilter.ย  I think I might tamp too hard but it’s a matter of getting the grind and tamp correctly for what I feel is the best taste for me.

Here is the pressure during the shot.ย  I’m quite happy with where it is sitting.

The following photos are during the second shot I did.ย  The first shot I tried as an espresso as I had tried the same bean and grind during our original adjustment attempts.ย  This time the bean showed it’s suuweetย notes ๐Ÿ˜€

This shot is with a different bean, photos of the shot during and after extraction.ย  Extraction time was 60ml in 42 seconds including the 8 second pre-infustion, so 34 seconds for the actual shot.

Finally here is my attempt at latte art ๐Ÿ˜€

The bean I used is best with milk so this was the only way to try it.ย  The taste, was smooth with hints of berry.


44 Responses to My OPV adjustment journey.

  1. Anger

    November 3, 2011 at 9:04 AM

    Well done ๐Ÿ™‚

  2. shotclock

    November 6, 2011 at 4:19 AM

    Thanks for the great guide. I adjusted my OPV this morning with no problems!!

    Here’s a couple extra hints for your readers:

    1. If the hose is really tight (mine was) you can use pliers right up near the fitting (as close to the cog as you can get) and wiggle the tube back and forth. That will help expand the opening and make it easier to remove

    2. If you can’t unclip the clip around the OPV cog, you can gently rotate the entire T-joint clockwise towards you. Then you can reach both sides of the clip more easily.

    Thanks again! ๐Ÿ™‚

  3. Anger

    November 6, 2011 at 1:26 PM

    To all: please be aware of the special note: Remember to put the hose back onto the OPV when you are testing it otherwise you end up with water everywhere and that can be a dangerous thing.

    Other than that, enjoy and remember who and where the good info came from…

    Nic’s Stuff ๐Ÿ™‚


    November 24, 2011 at 12:51 PM

    Definitely, what a magnificent site and educative posts, I will bookmark your site.Best Regards!

  5. mycuppa

    December 7, 2011 at 10:49 AM

    Excellent article Nic and thanks for the link to mycuppa and “comments”………Jeff.

    • Nic

      December 8, 2011 at 6:51 PM

      Thanks Jeff, no problems with the links and comments ๐Ÿ™‚

      There is no one I have more pleasure to link to ๐Ÿ™‚

  6. Feng

    January 26, 2012 at 7:18 PM

    Just stumbled across this via coffeesnobs. Thanks for a detailed post on how to make this adjustment. Mine currently sits at about 11 so I think I’ll make a full turn anticlockwise when I get motivated to purchase a blind (and a few other accessories).


  7. Will

    February 5, 2012 at 6:42 PM

    Hey there. Thanks for posting this up.

    I’ve just picked up a dual boiler for my partner but it’ll be sitting in the box for a month or so or whenever her renovations are complete.

    Hopefully the BDB works out of the box, otherwise I’ve booked marked this page for future reference. It’ll be interesting to see how it stacks up against my alex duetto!

  8. Feng

    February 24, 2012 at 11:00 PM

    Hi Nic. I ended up doing my own OPV recalibration. Your instructions were pretty clear. During extraction I now get it sitting just above 9 and it settles out to just under 9. Do you find now that it’s recalibrated, the pre-programed double shot buttons are way off in terms of what it thinks is the right volume?

    • Nic

      February 24, 2012 at 11:42 PM

      Yes completely right and from others comments they have found the same no matter whether a service centre did it or they did. It’s easy enough to reprogram them. I didn’t think to add that part, I haven’t reprogrammed mine as I only make one coffee at a time and found I like being able to watch where the blonding starts so only use the manual button.

      • Feng

        February 24, 2012 at 11:46 PM

        Thanks for the super quick reply!

        Cool.. I’m not going insane then. I ended up just playing around with the manual button and find that the adjustment was worth it.

        When I dismantled my machine, I found that the OPV adjustment cog was already about 1/8 rotated (weird :)). I only ended up need 7/8 of a turn (and the little line lines up lol).

        Thanks again for 1. the excellent write up, and 2. the super quick reply.

  9. Darryl

    February 26, 2012 at 6:04 PM

    Nic – I found your guide via a couple of Google searches. Believe it or not, the CoffeeSnobs forum are raving about your post over there.

    I spent most of the time getting the OPV clip out and had some fun tweaking the valve. I got it to 9 bar on the second try!!

    I ended up making a line marker since there was no markings on my OPV. It was nice to know how much I have turned.

    Thank you for your guidance.

    • Nic

      February 26, 2012 at 7:17 PM

      Hi Darryl, I’m glad I could help. Nic

  10. Richard

    February 29, 2012 at 1:26 PM

    Thanks Nic for the very informative post and great photos of the process of adjusting the OPV. I’ll be receiving my 900XL tomorrow and so will see if I need to make use of your excellent post.


  11. Bobby

    June 22, 2012 at 9:58 AM

    is it safe to do a OPV test like that. I just got my machine this week. How would I know if I need an adjustment?

  12. Bobby

    June 22, 2012 at 10:02 AM

    Also, when you opened up the machine. How did you feel about the quality of its components? Still worried about the life of the machine for the price paid.

    • Nic

      March 20, 2013 at 11:08 PM

      I realise that this reply was a long time coming. I haven’t had any problems with my machine but in saying that Steve’s comment when we first opened it up was “they are really cost conscious”…

  13. Johan

    June 27, 2012 at 12:37 PM

    Hi Nic,

    Thanks for posting this. I had the opposite problem with pressure never reaching beyond 8 bar. With your instructions it was easy to make the adjustment. Now at 9.5 bar.

    Cheers, Johan

    • Nic

      March 20, 2013 at 11:08 PM

      Hi Johan, I’m glad that I could help ๐Ÿ™‚

  14. Sam

    July 16, 2012 at 10:59 PM

    First of all THANKING YOU, simply for the effort you have put in.
    I had my bdb for about 2 weeks and I could not get the bar over 8 no matter how fine the grind is or which filter I used.
    After reading your clear instructions I just turn the cog with my fingers about 1 and a half turn- pronto perfectico-le-musica. My first shot was instantly transform-sweet and crematic (not sure if that’s a word) Anyway FANTASTIC!

    • Nic

      March 20, 2013 at 11:11 PM

      Sam it’s great to know that I can speak to the masses, I always aim for ease of use ๐Ÿ™‚

  15. Lucas

    July 23, 2012 at 10:19 AM

    I wanted to clarify the reference to the Sunbeam filter basket. Did you use the “Sunbeam double dual-floor filter basket” to test? Or the single dual-floor?

    Do you perform this test without coffee grounds?

    I’m also interested to know why it is different to the double dual-floor provided with the machine by Breville.

  16. Scott

    November 7, 2012 at 6:46 PM

    Thanks Nic you saved my bes900 from the trash heap! Got my machine back from a warranty service and was only getting around 5-6 bars. Followed your instructions and now back to about 8, might make some minor adjustments but now a very happy camper!

  17. Ino

    April 13, 2013 at 8:41 PM

    Hey – thanks for writing this guide! I was wondering what happened to my machine – seems that it de-calibrates (or beds in, depends on how you look at it) from new.

    I was getting ~9.2bar before the OPV would open. Then – through the first 100 shots – it came gradually down to about 7.9-8 bar.

    So I’ve opened it, and had a quick look at it. Mind you, I didn’t see the black mark on the adjusting cog – however – I thought it was a good idea, so I marked it myself – at least I know where it was.

    I’ve turned it a full turn – thinking that it would behave somewhat similar to yours, the pressure then shot up to 11bar before the OPV would open. So I backed off quite a bit of it – it now stands to about probably 2/5ths of a full turn and it’s back to its normal good self! It strikes me that it’s a little bit non-linear that adjustment – not sure how you get it when the thread is evenly spaced! ๐Ÿ˜€

    Thanks for making this easy!

    • Nic

      May 11, 2013 at 12:23 AM

      Hi Ino, I would keep an eye on your pressure gauges maximum pressure with the blind filter, it’s something I do about once a month, making sure that everything is still working the way it should.

      If you find that the pressure gauge is not staying where it is supposed to be then you might need to consider having the OPV replaced, they are plastic which personally I can’t see lasting, it was the main reason we replaced mine with a brass OPV almost immediately after we bought the BDB.

      • Ino

        May 11, 2013 at 9:32 PM

        That I have noticed over the past couple of mornings. I’ve had it to flutter at just a bee’s fart over 10 initially. It has come down now to about just under 9.5.

        It is not yet annoying us too much but I’d better make preparations to have it replaced with a brass one. I think that before the year is done I might be looking down the barrel of a brass OPV.

        The only mild concern is that I need to remember that I have a brass OPV if I need to send it for a service later on. It would be a rather unpleasant to get a refurbished one with another plastic OPV instead ๐Ÿ™‚

  18. carz

    May 9, 2013 at 1:14 AM

    sir, just recently the pressure gauge fluctuates, from preinfusion it goes to 9.5 then after a few seconds it goes to around 6 or 7 then after few secs goes back to 9.5 and back again. what is happening here? is this opv or something? or this is coffee staling? thanks sir this is the only detailed site regarding the opv

    • Nic

      May 11, 2013 at 12:18 AM

      Hi carz, have you tried using a blind filter to see what the pressure gauge is sitting on without coffee? If so what does it read. If this is sitting consistently at 9 – 9.5 bar there is nothing wrong with the pump. You will find that it is your coffee grind and technique. This can take some practice trying different grind levels and tamping weight. You will also find that different beans/blends will take a different grind level.

      Is your coffee fresh? Roasted recently, standard times are using beans within 3 weeks of roasting, don’t write off coffee a little over that time though, it depends on the beans used, Monsoon Malabar for one is best used after about 2 weeks but can still be fine for weeks after that.

      I’ve found that using the Breville Smart Grinder results in a consistent movement of the pressure gauge but it doesn’t go up down and back up again, it goes up then comes down around 1/2 to 1 bar during the shot. This I consider ‘normal’ for my technique of grinding straight into the portafilter and tamping, it isn’t consistent across the whole puck. I’m not completely happy with the results so I’ll keep experimenting with my technique.

      I hope some of this helps.

      • Alexandra

        April 16, 2014 at 11:50 AM

        Ther’es nothing like the relief of finding what you’re looking for.

    • Bill

      October 28, 2013 at 5:15 AM

      I have the same problem. Did you ever get yours resolved?

  19. chris S

    May 17, 2014 at 2:08 PM

    Life saver. Your article gave me the courage to pull my machine apart.

    Safety tip: if you remove the clip from the boiler side hose on the OPV, expect some excitement if the machine is hot. The hose blows off and steam goes everywhere.

  20. Martin

    August 6, 2014 at 3:54 PM

    Hi Nic, Do you know if the steam boiler can be adjusted with this method? I noticed another OPV looking thing just below the brew OPV.

    • Nic

      September 22, 2014 at 11:30 PM

      I honestly don’t know, personally I wouldn’t be mucking around with the pressure of the steam boiler.

      Is there something wrong with your steam pressure?

  21. Sean

    June 24, 2015 at 10:15 PM

    I’ve pulled my machine apart (thanks to you!) and notice that when it is ON and heating, the steam probes “leak” a ton of steam off the boiler. I assume this isn’t good? The O ring for these probes has been discontinued!?! Can you confirm this isn’t normal? And can I switch out other O rings? Thanks a million

    • Nic

      November 23, 2016 at 12:41 AM

      Sean, I’ve got to the point where I purchased a new steam kit, it didn’t come with a new o-ring so I had to use the old one. It’s not as bad as it was in terms of leaking, but it still gets that part of the machine really hot. I figure at this point, the machine is 5 years old, it’s going to have things that go wrong that I just have to live with.

  22. coffee guy

    July 8, 2015 at 2:59 AM

    Thanks a million for this technique! I was able to get mine dialed in to 8 bar, it was originally around 10.5. Shots are smoother and richer, and bottomless filter has a more even extraction. It seems like most higher end roasters recommend 7-8 bar for their espresso so my inner coffee geek wasn’t content with 10.5 bar.

    @Martin Check your operating manual for info to increase steam boiler temp. This will increase pressure. Lower temp to lower pressure.

  23. CallumW

    November 12, 2015 at 12:08 AM

    It works!!! ๐Ÿ˜€

    On a god day, by grind and tamp would have it sitting on 8.9.
    Any more and my bdb would bounce between 8.5-8.9 when hitting the OPV and make a weird ratchety noise.

    I think they should be set to 10 out the box as at least this way you can see how much your grind,tamp and bean age is affecting your pressure when over the “perfect 9”.

    I set mine to a smige over 10 and it no longer has that ratchety noise when hitting the OPV.

    A point to note for others trying it.
    Once you put the pipe back on and test, it will take at least 3-4 (single) pulls before the water circulates properly through the pipework and there are no more air bubbles affecting the pressure.

    Once it’s stable the needle should be pretty static on the dial. (I though I’d broken mine at first)

  24. Joe Bondi

    March 6, 2016 at 10:57 AM

    Aficionados my BES900 shows only max 6 bar pressure when making shots. Is this the gauge, the gasket or the OPV setting ? Thanks Joe

    • Nic

      November 23, 2016 at 12:35 AM

      Do you have a blind filter you can test it with?
      If not use the rubber plug and block the hole off, it should give you a close reading at least as long as there is no water leaking out.

      It might not be any of the items you’ve stated. Is your grind fine enough? What grinder are you using?

  25. Bob Penland

    November 22, 2016 at 10:12 PM

    I have a 1 1/2 year old BES920XL. I called Breville USA and was informed there are no repair parts available because this model is obsolete.

    I could not find any parts on line from second party sources.

    Any ideas?

    • Nic

      November 23, 2016 at 12:28 AM

      Hi Bob
      What parts are you looking for?

  26. Bob Penland

    November 23, 2016 at 9:09 PM


    I am sending the machine back to Breville for in-warranty repair. The shot temp set at 204 d F. only delivers water at 158dF.

    No parts needed at this time but in the future I want to be able to repair it.

    Before I retired in 1998 I sold, installed, repaired commercial espresso machines in northern California.

  27. Saqib Shafi

    December 3, 2016 at 7:06 AM

    Hey Bob. Any idea if the hose that goes into the OPV (the one with the silver clamp on it) can be purchased anywhere for replacement? I wasn’t able to find it on Or if any type of hose I can find in another supply shop could work? See here for why I ask:


  28. Saqib Shafi

    December 3, 2016 at 7:48 AM

    Bob, you can disregard the post above about a replacement hose. My OPV valve actually broke. Any idea where I can order one? See here:



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