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Just ordered my new Silvia... what next?

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  • #61
    Just ordered my new Silvia... what next?

    Originally posted by MrSnrub View Post
    So the idea is to run some water through the group head using the coffee delivery switch after steaming? Does steaming empty the boiler?
    I guess I need to do some research into how the machine works differently when the steam switch is on, compared to when it is off, and what happens when you run water through using the coffee delivery switch.
    From what everyone has said so far, I gather that as long as I go through a cleaning step at the end of my coffee-making session (and straight after steaming) of running water through the group head using the coffee delivery switch, my boiler will be safe.
    Yes & yes. Steaming doesn't use the pump, so obviously if you do enough steaming and/or leave it on for long enough, the water in the boiler will be depleted and you'll burn out your heating element. Running the pump (via the brew or water switch) after steaming is a good way to refill the boiler.

    It's also worth pointing out that you should check the steam knob every time you turn the machine on: often after cooling it's loose, and this can lead to water leaking from the steam wand while it's heating. I usually run the pump after turning on anyway, just to prime the boiler again and make sure it's completely full. :-)

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    • #62
      Originally posted by MrSnrub View Post
      From what everyone has said so far, I gather that as long as I go through a cleaning step at the end of my coffee-making session (and straight after steaming) of running water through the group head using the coffee delivery switch, my boiler will be safe.
      If you do this with the PF lightly locked in place, hit the brew switch then quickly lock unlock the PF a number of times (PF jiggle) it will help clean and dislodge coffee grounds from around the seal.

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      • #63
        Fantastic, thanks fruity and Yelta!

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        • #64
          Originally posted by MrSnrub View Post
          So the idea is to run some water through the group head using the coffee delivery switch after steaming? Does steaming empty the boiler?
          I guess I need to do some research into how the machine works differently when the steam switch is on, compared to when it is off, and what happens when you run water through using the coffee delivery switch.
          From what everyone has said so far, I gather that as long as I go through a cleaning step at the end of my coffee-making session (and straight after steaming) of running water through the group head using the coffee delivery switch, my boiler will be safe.
          You'll notice that when you use the Brew Switch or the Hot Water switch, the pump is running and replenishing the water in the boiler. When Steaming this doesn't happen. Take care not to totally empty the boiler when steaming if possible. Usually after steaming a 2 cup jug or if you notice the steam weakening, its worth refilling the boiler straight away to be safe.

          As soon as I finish steaming I flick the Steam Switch off and use the Hot Water Switch to refill the boiler. Let water pour through the steam wand until there's a steady stream for about half a cups worth. No mistaking when air has been pushed out of the boiler as you get that steady water stream and the half a cup or more helps cool the boiler/element down. After that I run some water through the portafilter to preheat it prior to grinding straight into the filter basket. Preheating helps stop the portafilter from stealing brew water temp somewhat like how a heatsink cools with heat transferance.

          I may be wrong here but I'll try to explain the Steam Cycle. With the boiler full, and the Steam Switch on, the heating element heats until the 140 deg C
          steam thermostat cuts power to the element to stop heating. As well as a temperature increase in the boiler there is a corresponding pressure increase. The boiler is in effect a sealed pressure vessel until the Steam knob is opened and starts to release pressure. At higher pressure steam is produced at a higher water temperature. At lower pressure, steam is produced at a lower water temperature. When the Steam Valve is opened via the Steam knob, steam exits through the wand due to the pressure inside the boiler being higher than outside. This causes the boiler pressure to slowly drop releasing more steam from the water which also causes the water level to drop correspondingly. This balance of pressure/temp continues until all the water is exhausted. The thermostat kicks in when it senses the temperature has dropped too far and heats whatever water is left. The issue here is that the heating element is increasingly exposed to air as the water level drops and needs to get hotter to transfer heat to trip the steam thermostat on top of the boiler shell. If left in this state too long, element damage can occurr.

          In case anyone is interested Water Boiling Point Temp v Pressure - http://www.engineeringtoolbox.com/bo...ter-d_926.html

          As a matter of routine, when I first switch on the machine I have the Hot Water switch on, Steam Knob open and then hit the Power switch so water is pumping into the boiler right away. When there's a steady stream of water through the steam wand, the boiler is full. After that I also hit the brew switch just to flush a little water through. May be overkill but as part of the regular routine doesn't take very long.
          Last edited by CafeLotta; 8 February 2013, 03:42 PM.

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          • #65
            Originally posted by CafeLotta View Post
            The issue here is that the heating element is increasingly exposed to air as the water level drops and needs to get hotter to transfer heat to trip the steam thermostat on top of the boiler shell.
            I pondered a little more on my previous reply and it raised a question. When the Silvia boiler is nearing empty, is heat primarily transferred to the thermostats by radiant heat inside the boiler or through conductivity via the heating element at its point of contact at the top of the boiler?

            The brew and steam thermostats are mounted on top of the boiler and sense temperature through the brass surface on the top of the boiler. When the boiler is full I would assume the water conducts heat to the internal surfaces of the boiler through the water which heat the brass uniformly. When the boiler is nearing empty, does radiant heat from the element to the internal surfaces of the boiler or the element's contact at the point of penetration at the top of the boiler act as the main heat source that trip the thermostats?

            I have been wondering why Rancilio went to a welded-in element rather than holes in the top of the boiler and an element which is secured by washers and a nut. Not sure if I'm right but it struck me that a welded-in element would transfer heat quicker across the top of the boiler than the previous arrangement. This would mean that the thermostats mounted nearby receive a quicker indication of temperature than the earlier arrangement. What do you think?

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            • #66
              Originally posted by CafeLotta View Post
              What do you think?
              I think that you think way too much.

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              • #67
                Originally posted by Yelta View Post
                I think that you think way too much.
                Force of habit. Used to work in Engineering design offices. Buggers you for life!
                Last edited by CafeLotta; 8 February 2013, 10:00 PM.

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                • #68
                  Originally posted by CafeLotta View Post
                  Force of habit. Used to work in Engineering design offices. Buggers you for life!
                  Habits, work habits in particular, are hard to break.

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                  • #69
                    First two mods done to the silvia - jetbreaker countersunk and a countersunk screw inserted, and a temperature sensor screwed down next to the brew thermostat for gronking.

                    The temperature variation is massive - cycling the boiler with the hot water button, it goes from a peak of 112 (about 3-4 seconds after the light goes off) to a low of 77 (just after the light comes back on).

                    I think a PID is in order, but I might try logging puck temperatures first.

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                    • #70
                      Originally posted by Hildy View Post
                      First two mods done to the silvia - jetbreaker countersunk and a countersunk screw inserted, and a temperature sensor screwed down next to the brew thermostat for gronking.

                      The temperature variation is massive - cycling the boiler with the hot water button, it goes from a peak of 112 (about 3-4 seconds after the light goes off) to a low of 77 (just after the light comes back on).

                      I think a PID is in order, but I might try logging puck temperatures first.
                      Have you actually tried making a coffee yet?

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                      • #71
                        Originally posted by Hildy View Post
                        First two mods done to the silvia - jetbreaker countersunk and a countersunk screw inserted, and a temperature sensor screwed down next to the brew thermostat for gronking.

                        The temperature variation is massive - cycling the boiler with the hot water button, it goes from a peak of 112 (about 3-4 seconds after the light goes off) to a low of 77 (just after the light comes back on).

                        I think a PID is in order, but I might try logging puck temperatures first.
                        Why not learn to use the machine stock standard, you may well be surprised my Silvia made great coffee for many years without the need to gronk or PID, the only change I made was to get rid of the Rancilio baskets and replace them with an 18 gram LaMarzocco.

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                        • #72
                          Originally posted by CafeLotta View Post
                          Have you actually tried making a coffee yet?
                          It has been a month, you know...

                          and that was almost a god shot - I actually blame my newbie roasting skills for the coffee being a bit bright (I didn't bring this one all the way to second crack).

                          I just find gronking more convenient - instead of watching intently to start timing when the element goes off, I just wait for the thermometer to hit 100 and hit the button.
                          Last edited by Hildy; 6 March 2013, 02:24 PM.

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