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Sunbeam 4800c Gauge & OPV Upgrade! Making very good shots now!

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  • #16
    Originally posted by noidle22 View Post
    looks good, i've just OPV'd my Breville BES820 but have yet to set the pressure and still need to fix the leaks.
    a problem i'm having now that i'm wondering if you encountered is that my steam pressure is now much lower, as the OPV is still drawing pressure away from the pump output when steaming.

    did you notice this effect at all? i'm not sure what to do to rectify it without implementing a split output from the pump that i can switch from one side to another to either use or bypass the OPV.

    cheers
    Hey noidle22

    I haven't noticed any problems with steam pressure at all with my machine. I would of thought that the 9-10 bar pressure set on the valve would be more than sufficient for just steaming some milk and the valve shouldn't let in any more air when the system is operating. However, my machine may work differently to your when steaming. Sorry i can't help any further.

    I had trouble with leaks with mine too but i used plumbing pipe sealant and it worked perfectly

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    • #17
      I'm wondering if sunbeam is uses BSP and NPT? If we use the wrong trend type, that would explain the leaking?

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      • #18
        Originally posted by ritsute View Post
        I'm wondering if sunbeam is uses BSP and NPT? If we use the wrong trend type, that would explain the leaking?
        Sunbeam uses a 1/8" BSP thread which all the ulka pumps have and was the same on the Vibiemme Domobar bypass valve i bought. The seal should sit snug in the pump as it has a recess which my valve didn't have so that's why i needed the sealant.

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        • #19
          turns out the steam problem was caused by the steam diverter valve and body. there was some bad seal in there somewhere, stripped it down, replaced arm o-ring and it's back to good pressure. even better than before the OPV i think.

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          • #20
            karl-

            Were you using a single floor basket before you did the OPV mod?

            I have the same machine and with just the basket mod and a really good grinder the shots taste really good, I was told that the pressure mod was not necessary?

            Any Idea what the pressure is normally before you changed it?

            I need to decide if I should do it or not, thanks

            also in the photo it looks like you have a chromed brass group handle, it there one around to fit this machine?

            La pavoni use a 51mm Group handle, I wonder if it fits? would be nice to have a naked with a tripple basket for restrettos

            C-
            Last edited by C-man; 1 October 2012, 12:47 PM.

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            • #21
              Originally posted by C-man View Post
              karl-

              Were you using a single floor basket before you did the OPV mod?

              I have the same machine and with just the basket mod and a really good grinder the shots taste really good, I was told that the pressure mod was not necessary?

              Any Idea what the pressure is normally before you changed it?

              I need to decide if I should do it or not, thanks

              also in the photo it looks like you have a chromed brass group handle, it there one around to fit this machine?

              La pavoni use a 51mm Group handle, I wonder if it fits? would be nice to have a naked with a tripple basket for restrettos

              C-
              Hey C-Man

              As i mentioned in the first post, I did upgrade to a single floor (unpressurised) basket and found that it helped a lot alright. I just seen your post of the triple basket mod you did - looks good. I find though if i pack the double up good, I get around 21 grams which is around a triple anyway.

              I did upgrade to a single floor basket before the mod and the shots did taste good alright but the key thing with the OPV mod is..

              1 consistency - with the pressure directly depending on the exact tamping and grind every time, you can pull a good tasting shot but with any slight change in either tamp or grind, the flow might be slower/quicker and the shot would taste different. With the OPV mod, no matter how light you tamp or grind, the pressure will be set to 9.5 bar and won't go over and shot taste is more consistent. Before the mod, the pressure would read around the 12-14 bar range

              2. Bitterness - Although I was getting decent shots, i found there was always the slightest bitterness taste no matter how good the shot was. Since the OPV mod that bitterness is gone.

              I just use the standard group handle that came with the machine.

              Just to note, if you're happy with your shots, just leave it as is. I've had my machine for 3 years now and was never completely happy with my shots and with the added parts that were cheap enough and didn't take long to fit, i have a more consistent better tasting shot machine.

              Karl

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              • #22
                Thanks for the reply karl_

                Hmm, Every shot from even expensive machines I have tasted had a slight bitterness to them I guess?

                I think I will do the mod, if you were doing it again, which OPV would you order? the Expobar?

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                • #23
                  Hi Karl,

                  Great Mod. A quick question about machining the OPV so its not pressed against the pump - can you point me in the direction of the thread that was contained in? I post a rough set of guidelines of how you got it done? This seems the part that has potential to cause the most grief.

                  cheers,

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                  • #24
                    I find that with my really good grinder and the single floor basket I get good shots for the first 15-20 seconds,

                    then after that I guess the pressure builds causing the shot to speed up, blond, and go bitter, If I keep the shot restretted to no more than say 18 seconds

                    it is sweet but I am not getting the full dose. Hopefully the OPV mod will fix that.

                    Comment


                    • #25
                      Originally posted by willaitch View Post
                      Hi Karl,

                      Great Mod. A quick question about machining the OPV so its not pressed against the pump - can you point me in the direction of the thread that was contained in? I post a rough set of guidelines of how you got it done? This seems the part that has potential to cause the most grief.

                      cheers,
                      don't want to threadjack or anything, but i had to do the same thing as i've used the same OPV in my machine, with the same pump. i just used a dremel with the cutting wheel on it to cut off about 3-4mm of the thread i think then just used a fine file to smooth off the end.

                      to measure the correct amount that you need to cut off if you aren't sure, just put something into the pump outlet up to the point that it just doesnt touch that internal piece, mark it off then compare that length to the OPV inlet and cut off the excess. it should be around 3-5mm i think.

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                      • #26
                        Originally posted by C-man View Post
                        Thanks for the reply karl_

                        Hmm, Every shot from even expensive machines I have tasted had a slight bitterness to them I guess?
                        . Th
                        I think I will do the mod, if you were doing it again, which OPV would you order? the Expobar?
                        I hope you notice a difference in the taste if you go ahead with the mod!

                        I guess you want to make sure that the ajustment for the valve is easily accessible and easily adjustable. Mine is easily adjusted with a scredriver and when i screwed my valve in, it faced against the wall nicely for me to just drill out for adjustment access.

                        Also the thread is important, that's one reason i got the Vibiemme Domobar as the thread was the same so it easily bolted in (1/8" BSP thread).

                        I reckon the expobar valve should be fine, i guess whatever valve is a decent make and cheapest

                        good luck

                        Comment


                        • #27
                          Originally posted by willaitch View Post
                          Hi Karl,

                          Great Mod. A quick question about machining the OPV so its not pressed against the pump - can you point me in the direction of the thread that was contained in? I post a rough set of guidelines of how you got it done? This seems the part that has potential to cause the most grief.

                          cheers,
                          Hi willaitch,

                          Your right, this is what has the potential to stuff up the pump from what I read in the thread.

                          It's nic's stuff: » BES900 and the brass OPV… Nic's Stuff

                          Have a look

                          Comment


                          • #28
                            Now I can't wait to do this mod!

                            the pressure is too much! I can't take it anymore! PRESSURE!

                            It's gettin to me! AHHHHHHHHHHHHHHHHH

                            Comment


                            • #29
                              Originally posted by karl_2020 View Post
                              I got the the Vibiemme valve for $39.75 online from stefanos espresso care. However, I was later contacted by Disave espresso parts in Vic, I could have gotten an expobar valve for $25.50 + $5.50 postage.

                              Stefanos sell gauges from $30 upwards but you can get 16 bar pressure gauges online from RS components in NSW for $14.50 upwards. I got mine on ebay for $20 which is another option.
                              Sense the expobar valve is here in Australia and the Vibiemme is all the way in USA, I would prefer to order the Expobar, but are the thread sizes the same?

                              I would like to stick with what worked for you to simplify but can't seem to find Vibiemme here unless someone else know where?

                              I see a cheap pressure gauge, but don't understand how it can be 16 bar and have 20 divisions on it? also I guess you need to buy the thin copper tubing seperate?

                              here is the link http://australia.rs-online.com/web/p...auges/7008878/

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                              • #30
                                Thanks to Karl for all the help,

                                I have everything on order now.

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