This isn't a post about coffee brewing technique - there's lots of great sites and posts dedicated to this on the interweb. I love my Rancilio Siliva - I look at it as a simple, rugged, reliable machine for making coffee. It has it's limitations however, and one of them is the ability to manage brewing water temperature. There is no temperature indication on the stock Silvia, and the brew water thermostat on the boiler has just two setpoints - water heating lower limit, and upper limit.
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| Auber PID Temperature Controller - White LED version |
The installation of a PID (proportional–integral–derivative) temperature controller is designed to resolve these limitations by providing temperature display, and automated brewing and steaming functions with the ability to customize key settings - such as brew water temperature, brewing time, and so on.
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| Completed PID installation on the Rancilio Silvia - note the box to the right of the group head with the white LED temperature display. |
PID Installation
The Auber installation manual is clear and self explanatory. I don't intend to reproduce a manual here, just provide some photos and tips / observations from my installation experience.
Installation of the SSR (solid state relay) is fairly straightforward. It installs next to the pump on the main chassis of the machine. The Auber kit comes with one nut, bolt and washer for installation through the bottom vent holes. I drilled a second hole and added a second fastener to help hold the SSR a bit more securely, and ensure the bottom surface and heat transfer silicone is as tight as possible for best possible heat transfer and component reliability.
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| Hole drilled in chassis for second fasterner |
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| Note the heat transfer silicone - I cleaned this up for a neater final installation. |
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Top view. Note the scale on the black chassis to
the right of the SSR from a leaking high pressure hose fitting. |
One other tip - this installation places the SSR almost directly below the high pressure stainless braided hose.
I made sure to correct a leak in the 90 degree elbow fitting using some pipe dope. I also added a small plastic sheet to deflect any water from the SSR in the case of a future leak.
Wiring the controller was straighforward, again, the instructions were quite clear. Just one tip - I inverted the machine for performing the wiring and prep for adhesive tape installation. This made it very easy to access the connections, and apply pressure to the PID when applying the adhesive tape.
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| I temporarily taped the PID enclosure to the steam wand to keep it out of the way during wiring termination. |
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| PID Controller Wiring Complete |
Note - when I cleaned the surfaces for installation of the PID - most of the ink came off the UL certification label. I ended up removing the certification label to ensure a clean surface for intallation of the PID. I don't recommend removing the certification label. One other thing I did was to use a heat gun to heat the metal sheet where the PID was to be installed, and gently heating the adhesive also. This allows the adhesive tape to completely adapt to the surface inconsistencies for the best possible bond.
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| Cleaning the PID Controller installation surface |
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| Certification Label |
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| PID Controller installed. Working with the machine inverted makes it easy to apply pressure to improve adhesion. |
One other thing to consider when installing these kits - the Rancilio Silvia has PVC electrical wiring insulation - which becomes brittle with heat and time. My machine is 12 years old - and I was very careful to avoid cracking the wiring insulation and terminal insulators. Some of the terminal insulation broke anyway. When I
insulated the boiler using fibreglass insulation - I was careful to reorganize the wires, zip tie them together to avoid having any wires or connectors too close to the heating elements. See photo below. This should enhance reliability of the connections. I can see that if I expect to get 20 years out of the this machine - I may end up having to replace the wiring.
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| Wiring organization using zip ties |
Conclusion
How does the new PID temperature controller work? Simply fantastic - it's great to have fine control over brew water temperature, and a much better understanding of what's happening with the critical brew variables. Result - better tasting coffee (although I still have a long way to go). I wish I had got this upgrade done years ago.
Sources and Links
I hope you found this post useful. Feel free to ask questions in the comments section below. I answer all questions. If you're interested, you can help support this site by using the following links to Amazon.com in the United States. I purchased my PID kit directly from Auber Instruments:
https://www.auberins.com/ My go-to place for genuine Rancilio Silvia parts in Canada is Espressotec.com.
