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  • Sunbeam 6910 pressure adjust

    Hi,

    Is it possible to adjust the pressure valve on a stock em6910?

    I've been looking for the OPV, I think its mounted directly on the pump outlet, but I wanted to check before I start tearing into the machine.

    Thanks!

  • #2
    Originally posted by coffee_nik View Post
    Is it possible to adjust the pressure valve on a stock em6910?
    No. It's a safety valve only.

    Comment


    • #3
      Originally posted by noidle22 View Post
      No. It's a safety valve only.
      Thanks noidle. So i guess if the pressure seems a bit low I should probably take apart and clean the pump as a first step?

      Comment


      • #4
        Originally posted by coffee_nik View Post
        Thanks noidle. So i guess if the pressure seems a bit low I should probably take apart and clean the pump as a first step?
        First, test it with a dual wall basket or with the cleaning disc in place. See how fast the needle rises until it stops and where the needle stops. Once under pressure, check the outlet into the drip tray for any water leaking into it.

        If you achieve an acceptable rise of the needle (from the needle beginning to move to when the needle stops in 2-5 seconds) and a stable full pressure (around the middle/top of the orange zone) but are having poor espresso extraction results, the issue may be the grind or coffee beans.

        Also, check the volume of water coming from the group head. Press manual and collect the water from the group head over 30 seconds. How much do you get?

        There's some more things to check or test but we can start here.

        Comment


        • #5
          Originally posted by noidle22 View Post
          First, test it with a dual wall basket or with the cleaning disc in place. See how fast the needle rises until it stops and where the needle stops. Once under pressure, check the outlet into the drip tray for any water leaking into it.

          If you achieve an acceptable rise of the needle (from the needle beginning to move to when the needle stops in 2-5 seconds) and a stable full pressure (around the middle/top of the orange zone) but are having poor espresso extraction results, the issue may be the grind or coffee beans.
          Hi Noidle,

          Thanks again for the reply.

          The needle moves to almost exactly the 12 o'clock position with a blind filter. When i first got the machine it went to around 2/3 o'clock, but I'm not sure if its weaker pressure now or maybe the gauge has drifted out of calibration.

          I just did a full tear-down of the pump and it was pretty much like new inside even though its 10 years old and averages at least 1 coffee a day. The rubber valves were all still soft and clean.

          When the pressure is building I can see water moves from the OPV outlet, but it stops once pressure is built up. I also clamped the OPV outlet tube and the pressure didn't go any higher.

          I'm getting reasonably OK shots out of the machine, so its possible the pump is running OK pressure, I'm just a bit curious to why the needle is reading lower than before.

          Comment


          • #6
            I wouldn’t worry about it too much. As long as nothing is leaking and you’re getting acceptable results it may not even be an issue. I completely ignore the gauge on my 6910 when I’m making espresso, I only refer to it when I’m running a backflush. I’ve got no idea really what it shows when I’m making coffee.
            noidle22 has forgotten more about these machines than I’ll ever know so I’d trust his advice. If everything else is the same such as dose, grind setting, coffee, water etc. then it could just be that the gauge is playing up, but not itself an indication of a problem with the machine. I know these gauges stop working altogether sometimes, usually due to a blockage so maybe you’re seeing the early signs of this?

            Comment


            • #7
              Still need to do your flow test as noidle suggested. You can test at the pump outlet, and at the group (remove the shower screens and the valve thing above the screens as well)

              Comment


              • #8
                Originally posted by Jackster View Post
                Still need to do your flow test as noidle suggested. You can test at the pump outlet, and at the group (remove the shower screens and the valve thing above the screens as well)

                Hi Jackster,

                I tested at the group head, I got 233 ml for 30 seconds.

                Also noticed my pump is intermittently surging exactly like the one in the video below when I use the cleaning disk, the needle drops from 12 o'clock to 10 o'clock and back with each surge:

                https://www.youtube.com/watch?time_c...&v=OTdHncCbouU

                Thanks,
                Nik.

                Comment


                • #9
                  Originally posted by coffee_nik View Post
                  Also noticed my pump is intermittently surging exactly like the one in the video below when I use the cleaning disk, the needle drops from 12 o'clock to 10 o'clock and back with each surge
                  That's a faulty pump. That's the same way nearly all of them fail, the pump works fine under no pressure and flows the correct volume of water but once it's under extraction pressure, it can't maintain it and surges.

                  It is possible to install an over pressure valve from a Breville Dual Boiler machine if you want to play with it. This does require sourcing of a different tube to connect the OPV to the thermoblock inlet fitting on the Sunbeam. I've found that the teflon tubes from old Saeco automatic machines work well. You can buy the tubes online but depending where you are, chances are there's a few dead Saeco's around that you can salvage the part from.
                  Here's an example of a tube that you would need:



                  It's just a regular teflon tube as found in most machines, this image of it just had a black cover over it as a few Saeco's use them. Basically you need a tube with a flare/compression fitting on one end with a 1/8" female thread (to connect to the thermoblock) and a regular o-ring tube fitting on the other end (to connect to the OPV outlet). I found the Saeco tubes to fit well and not leak, I had some leaks with some other brand tubes.

                  It's up to you whether you want to pursue this. The Sunbeam can make a good enough coffee in stock form really, I was never really convinced the OPV installation improved the results in the cup significantly, mainly just did it to see what happened.
                  It does reduce the strain on the pump though as it will never need to work at full capacity. This is mainly the reason the pumps fail in this way in the Sunbeams I think, they are constantly at near 100% duty when making a shot.

                  Comment


                  • #10
                    Originally posted by noidle22 View Post
                    That's a faulty pump. That's the same way nearly all of them fail, the pump works fine under no pressure and flows the correct volume of water but once it's under extraction pressure, it can't maintain it and surges.
                    Thanks noidle, that confirms what I was suspecting.

                    Its interesting, the pump looks fine internally after I took it apart - the o-ring and ball which are supplied in rebuild kits look to be in good condition. I'm curious to know what wears out as all the rubber bits are like new.

                    Thanks for the tip on the Breville OPV, although I suspect by the time I hunt down all the bits and pieces it will probably cost more than the pump below on ebay with adjustable OPV:

                    eBay link removed as per Site Posting Policy

                    It looks to be easy to install with some minor piping adjustment, the only downside is its not calibrated to a particular PSI, so I would have to rely on the built in gauge and I guess just tinker with the pressure until i get a nice extraction.

                    I recall a thread years ago about a portafilter gauge being snail mailed around for calibration, I might see if its still a thing.
                    Last edited by Javaphile; 22 December 2019, 10:08 PM. Reason: Removed eBay link

                    Comment


                    • #11
                      Originally posted by coffee_nik View Post
                      Thanks noidle, that confirms what I was suspecting.

                      Its interesting, the pump looks fine internally after I took it apart - the o-ring and ball which are supplied in rebuild kits look to be in good condition. I'm curious to know what wears out as all the rubber bits are like new.

                      Thanks for the tip on the Breville OPV, although I suspect by the time I hunt down all the bits and pieces it will probably cost more than the pump below on ebay with adjustable OPV:

                      It looks to be easy to install with some minor piping adjustment, the only downside is its not calibrated to a particular PSI, so I would have to rely on the built in gauge and I guess just tinker with the pressure until i get a nice extraction.

                      I recall a thread years ago about a portafilter gauge being snail mailed around for calibration, I might see if its still a thing.
                      That's interesting, never seen anyone else sell or advertise an OPV setup for a Sunbeam. I've seen that guy around on ebay a lot recently selling parts for many coffee machines, he might even be on the forums. Would seem odd if he wasn't to be honest if he's into these sorts of products and modifications.

                      $70 for that setup is still pretty expensive but for the convenience it's not bad. He's making a fair profit on it that's for sure.

                      The portafilter gauge was only for E61 machines if I recall so it won't fit the Sunbeam.

                      Comment


                      • #12
                        Originally posted by noidle22 View Post

                        $70 for that setup is still pretty expensive but for the convenience it's not bad. He's making a fair profit on it that's for sure.

                        The portafilter gauge was only for E61 machines if I recall so it won't fit the Sunbeam.
                        Hmm doesn't seem too bad retail price wise to me, the cheapest pump I've seen is $40, the OPV is another $20 at least and there is another angle adapter. I guess like any industry if you compare wholesale to retail pricing it seems a lot, but I figure they have designed the kit and have to hold inventory.

                        I'll definitely have to confirm the 6910 portafilter thread pitch, I recall they changed it on newer variants or something.

                        Unfortunately I cant check mine as the bottom of the portafilter sheared off when I tried to unscrew the spout (on the plus side it was machined into a naked filter . I'm not sure if it was a common problem, but mine was machined too far at the factory and the bottom was almost paper thin.

                        I'll have to check my parents machine next time I visit, although I'm suspecting they have the newer incompatible portafilter thread patch as they have the newer style drip tray.

                        Comment


                        • #13
                          The new pump and OPV arrived yesterday and installed without too much drama.

                          Pressure builds up so much quicker now, and adjusting the OPV lets me make the gauge sit wherever I want with a blind filter.

                          Next steps are to try and get a calibration of the stock gauge which only has gold/brown/black/red zones rather than PSI numbers.

                          Looking at other posts on the internet I can do it based on the OPV flow rate with a blind filter in place.

                          Note that if you decide to install the kit you will need a bunch of different thinish shifting spanners (10 & 12 especially), and a lot of teflon tape as the silver elbow piece thread was pretty loose.

                          Also you need to bend the top pipe 90 degrees, but that's not too bad as it has a big loops of tubing (assuming for vibration?) so plenty of pipe to work with.

                          I manged to get the OPV adjustment facing towards the back of the machine, so its really easy to adjust, just remove the 4 screws to the plastic back panel. I could probably drill a hole in the back panel for even easier access, but I don't think I will be adjusting that much.
                          Attached Files

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                          • #14
                            Nice job on that one!

                            Comment


                            • #15
                              Thanks to all the posters on this thread, especially to Noidle for the comment on the failing pump.
                              I have two 6910 machines where I get surging during the espresso pour, they are both very early machines, with early 400 numbers on them.
                              I will get another couple of pumps and see how we go.

                              Did you realise you can buy them from China.
                              The steam pump is not much cheaper, bout NZ$10.00.
                              Not sure about the other one.

                              Robin

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