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  • #31
    Re: PID Silvia Sydney

    Hi Bloop,
    Originally posted by bloop link=1143536728/15#29 date=1144661929
    The thermocouple wire doesnt seem to be soldered at the end, anyone know if normal lead solder will do the job or does that have too low a melting point?
    You can do this one of three ways..... Youre correct where the use of Soft Solder is concerned.
    Probably the easiest, if you can get hold of it, is to use Silver Solder as this can be achieved with a standard Propane Gas Torch.
    Second method is to use a small Crimp Link or Lug with a good pair of crimpers that will guarantee a high pressure crimp. Just twist the two t/c wires together then insert into Link/Lug and then Crimp.
    Third method is to autogenously weld the two t/c wires together but without suitable equipment, this is next to impossible to do. If you know someone with a TIG Welding outfit, they should be able to do this for you.

    My money is on the first two methods for DIY at home though.

    Originally posted by bloop link=1143536728/15#29 date=1144661929
    Mal, you piggy-backed power off the Mokita? If so did you splice the wire or is there some kind of "double adaptor" attachment available for this kind of job?
    Im not entirely sure of the Wiring Arrangement of the Silvia compared to the Mokita but all I did was remove one of the downstream cables from the Main Power Switch (with unit unplugged of course), attached a "Piggy-Back" Spade Connector (from Dick Smiths) to this cable and then re-attached to the Switch. I then attached the power cable to the Controller via the newly created "spare" lug and all was good . Im sure Ive seen a schematic/wiring diagram for a Silvia posted up here before so maybe a search will turn up where this is located.

    All the best,
    Mal.

    Comment


    • #32
      Re: PID Silvia Sydney

      Thanks Mal, Ill try and get hold of some silver solder. I dont think Dick Smith or Jaycar have them, might have to try a jeweller.

      I then attached the power cable to the Controller via the newly created "spare" lug and all was good Smiley.
      Did you connect the neutral cable as well or just the active?

      Thanks!

      Comment


      • #33
        Re: PID Silvia Sydney

        Originally posted by bloop link=1143536728/30#31 date=1144678648
        Did you connect the neutral cable as well or just the active?

        Thanks!
        Yep,

        Connected the Neutral directly to where the Main Neutral terminates on the Connector Strip where all incoming cables terminate. I also included an Earth just in case that at some later date I upgraded the controller box to a s/s one 8-) that would then require bonding to Earth. Until needed, have just left it coiled up out of the way at both ends. Better doing it now rather than having to pull everything apart and start over at some later date .

        Cheers,
        Mal.

        Comment


        • #34
          Re: PID Silvia Sydney

          Hi, Bloop -

          Sounds like you are going to earn your stripes on this job!

          FWIW, heres the way I make my t/c probes:

          Strip 5-10mm of wire (careful not to nick wires), then twist the bare wires *tightly* together. Use your wire cutters to cut away excess, leaving 4-5mm of bare twisted wire exposed.

          Get an uninsulated crimp-type ring terminal (ring size #6, crimp tube for wire size #14-#16). Push t/c through crimp section, insulation and all, so that the tip of the bare twisted wire stops around 2mm short of the ring opening (if you get much closer, there will be no room for the head of the screw when you fasten it down).

          Using less pressure than normal, crimp the connector down on the insulated wire, being careful not to cut through the insulation.

          Solder the bare twisted wires to the crimp terminal, applying the heat from electric soldering iron to the *back* side of the ring connector. I use soft lead, resin-core solder. I have also tried silver solder, but it doesnt like to stick to things in my shop!

          Use small wire brush on Dremel tool to shine everything up, front and back, to enhance thermal transmittance.

          I use type T wire, not type K. Type K is much more difficult to solder, but I think this procedure will probably work anyway.

          If you have trouble getting this to work, Id be happy to send you a T-type all made up and ready to go.

          -- JGG

          Comment


          • #35
            Re: PID Silvia Sydney

            Here is a picture of piggyback terminals.


            Having unplugged the coffee machine from the wall....!

            Wires from the PID 240V terminals are crimped to the piggyback.  Existing wires are slid off the switched side of the coffee machine switch and slid onto the lug pointing upwards on the photo.

            The piggyback is then slid onto the switchs male terminals where the original wires were.

            Makes sense?

            This configuration ensures the PID automatically turns on when the machine is switched on.

            If for some reason you want the PID on permanently, irrespective of whether the machine is on or off, attach to the powered side of the coffee machine switch, or-----wire the PID to a power chord with its own 3-pin 10 amp plug and plug that into the wall.


            Robusto

            Comment


            • #36
              Re: PID Silvia Sydney

              Thanks for all the help guys.

              Connected the Neutral directly to where the Main Neutral terminates on the Connector Strip where all incoming cables terminate.
              Mal, any reason why you didnt connect it to the switched side of the circuit?

              Solder the bare twisted wires to the crimp terminal, applying the heat from electric soldering iron to the *back* side of the ring connector. I use soft lead, resin-core solder. I have also tried silver solder, but it doesnt like to stick to things in my shop!
              JGG, with soldering Im just worried the boiler will get hot enough to melt the solder, silver solder has a higher MP, so I thought thatd be the way to go seeing as I dont have access to welding equipment. Do you know what the highest temperature the boiler can get to? If I cant get it to work Ill take you up on your offer

              The piggyback is then slid onto the switchs male terminals where the original wires were.

              Makes sense?
              Makes perfect sense, and thanks for the pic Robusto. I went to Dick Smith today but they didnt have any of those piggyback connectors, nor did Jaycar. The Dick Smith guy was even more clueless than I was : Looks like Ill have to do some hunting around for these, it helps now that I know what they look like

              Would it work if I just screw the twisted thermocouple wire directly to the boiler where it shows in the following pic?

              Comment


              • #37
                Re: PID Silvia Sydney

                Hi, Bloop -

                The overheat thermostat on Silvia is set to shut things down at 165C. 60-40 solder has a melting point of 186C. So even allowing for some play in tstat setting, and some overrun in temp after de-energizing the heater, I think the 60-40 is probably fine.

                As far as the splitter for your power connections, if you cant find the right hardware (check www.waytekwire.com) you could always build a couple of little pigtails. Crimp 2 short wires (25mm?) into a single female push-on. Then crimp a male push on to the 2 free ends and you have a splitter that should work. Ive never tried this (I use the hardware splitters), but have seen it recommended in some other discussion groups.

                -- JGG

                Comment


                • #38
                  Re: PID Silvia Sydney

                  Bloop, try a car accessory place such as Supercheap Auto for the piggybacks and other terminals.

                  The Silvia boiler gets to almost 150° during steaming, and that is about 30° below the melting point of solder.

                  But there is no need to solder a terminal onto the thermocouple.
                  There are many, many posts about the best spot to locate it on top of the boiler. Try google alt.coffee.

                  I dont think it really matters, since most of the time the boiler will be kept at a constant, even temperature by the PID.

                  Remember, the PID is giving you a constant temperature in the run up for brewing, not during the extraction. You cant expect the gadget to handle a sudden 60 ml change in water supply--- Silvias design will do the hard yards and keep the water temperature at the group constant for those vital 25", not the PID.

                  Your picture shows the steam thermostat (the one on the right).
                  Just loosen the thermostat hold-down screw, and wedge the thermocouple end under the bracket. Make sure it is secure and wont slip off.

                  Feel free to experiment --- if you find that particular spot unsuitable, try the middle one between the two thermostats, or the left hand one.

                  Robusto

                  Comment


                  • #39
                    Re: PID Silvia Sydney

                    Originally posted by bloop link=1143536728/30#35 date=1144757285
                    Mal, any reason why you didnt connect it to the switched side of the circuit?
                    Hi again Bloop,

                    No particular reason really, other than it was the most convenient location.... Its not necessary or desirable in certain situations to switch both the active and the neutral. I know one often finds this arrangement in European manufactured equipment though. In some ways, its the old horses for courses argument again.

                    For this purpose, connecting from the switched side of the Neutral cable is ok too, providing it is easy to do on the Silvia.

                    Cheers,
                    Mal.

                    Comment


                    • #40
                      Re: PID Silvia Sydney

                      Originally posted by robusto link=1143536728/30#37 date=1144758778
                      Remember, the PID is giving you a constant temperature in the run up for brewing, not during the extraction. You cant expect the gadget to handle a sudden 60 ml change in water supply--- Silvias design will do the hard yards and keep the water temperature at the group constant for those vital 25", not the PID.

                      Robusto
                      Hi Robusto,

                      This is not entirely true..... it is possible to configure your controller so that it will react quickly to any detected change in Boiler Temp. Ive got my t/c mounted right next to the Cold Water Inlet on my Mokita so that it will switch on the element ASAP and then have set the PID parameters to complement this. Using a micro-bead t/c connected to a Fluke with built-in t/c compensation, I tried what Sparky has suggested many times and placed the t/c bead on top of a coffee puck and pulled a few shots. The maximum deviation from the optimal of 93deg C on top of the puck, was a droop of only 2deg C.

                      Since the Mokita has a more direct path from the Boiler to the Group Head than the Silvia, the actual Setpoint is never more than 101deg C, with about a 7.5deg gradient through to the top of the puck while brewing a double shot in 25-28 seconds. Recovery time is pretty fast in between shots with the Boiler being ready to go again by the time youve knocked the spent puck out, cleaned out the PF basket, ground a fresh dose into the PF, distributed and tamped. Ive never actually timed this but its only 2-3 minutes all up. If the PID parameters are just left as the AutoTune has set them, this type of turn-around is impossible, so it pays to learn a bit about the workings of digital PID controllers so that you can tune it to the optimum of your desired output.

                      Cheers,
                      Mal.

                      Comment


                      • #41
                        Re: PID Silvia Sydney

                        Every thread needs a PIA, and we were missing one here. So I will volunteer.

                        I do not like putting the t/c under the screw head for the steam thermostat. The primary reason is that it lifts the retainer bracket up and off of the boiler surface. This can allow a gap between the sensing surface of the steam tstat and the boiler surface. Tight contact between the tstat and the boiler is necessary for accurate performance of the tstat. Thermal grease is not a substitute for tight contact.

                        For this reason, I always put the t/c under the leftmost screw holding the brew thermostat. (This also happens to be one of the hottest spots on the top of Silvia, for some reason).

                        If I were going to use a simple twisted wire termination on my t/c, I think I might loosen the bracket, wedge it under the *brew* thermostat that is effectively being replaced, then re-tighten bracket.

                        -- JGG

                        Comment


                        • #42
                          Re: PID Silvia Sydney

                          Appreciate what you are saying Mal, and I know Sparky disagrees with this, and I dont yet have a PID.

                          But  there have been numerous experiments done by  Greg Scace and others at  Google alt.coffee similar to yours, using a Silvia without a PID---and the result is a remarkable one or two degree variation during the pour, thanks to Silvias thermal stability.


                          Robusto



                          Comment


                          • #43
                            Re: PID Silvia Sydney

                            That makes sense, JGG. Another temptation would of course be to place the thermocouple on the topside of the bracket, under the bolthead. But that may slow response time: water heats the boiler, boiler heats the bracket, bracket heats the t/c probe.

                            Robusto

                            Comment


                            • #44
                              Re: PID Silvia Sydney

                              Originally posted by robusto link=1143536728/30#41 date=1144780216
                              Appreciate what you are saying Mal, and I know Sparky disagrees with this, and I dont yet have a PID.

                              But there have been numerous experiments done by Greg Scace and others at Google alt.coffee similar to yours, using a Silvia without a PID---and the result is a remarkable one or two degree variation during the pour, thanks to Silvias thermal stability.


                              Robusto
                              Im not actually sure what I disagree with. I know coffee thermometry is not straightforward and there are plenty of ways to get inaccurate results, which just makes things more confusing, because then who do you believe. The bottom line consensus for the Silvia is that you can get the temperature stable to about 2C in the Silvia as the cold water doesnt have time to mix with the hot boiler water during a shot. So all you have to do with the PID controller is get it to stabilize the boiler temperature between shots and the Silvia will do the rest.

                              Trying to stabilize the shot temperature with a PID controller during the shot is not a great idea unless you monitor the actual brew temperature to see how it is working. You can get an idea of what is possible by looking at my PID Faema Family data. The thermal response of the system is very slow (about 10 sec), so you cant control the brew temp effectively using feedback on these timescales. In my machine the PID would pick up the tail of the profile and keep the total deviation within a few degrees. This is probably what Mal is referring to. There is no need to do this on Silvia, as the cold water doesnt mix effectively with the brew water during the shot.

                              The best thing about PID control is that it gives you the ability to make repeatable shots, as long as you have the rest of your preparation routine sorted out.

                              So in the end Im sure what Im agreeing or disagreeing with. A PID controller on nearly any single boiler machine has nearly immediate benefits for shot-to-shot repeatability.

                              Cheers,

                              Mark.

                              Comment


                              • #45
                                Re: PID Silvia Sydney

                                Spot on Sparky!

                                Robusto

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