Rancilio Silvia Hacking

I have been getting a little tired of temperature surfing on my Rancilio Silvia coffee machine, so I decided to purchase a PID controller for it. Auber instruments had a pretty good deal going, so I ordered it. What follows is a post showing the installation and results...

The kit itself is fairly small and unassuming, but the installation is quite involved, so don't get too cocky. It took me about two hours to complete the job, and I am pretty good with electronics ;)

Pictured roughly from left to right are:

• The wiring harness, and zipties
• The solid state relay for switching the heating element
• The PID and timer controller
• The resistive temperature sensor

I was a little surprised at the resistive (instead of thermocouple) temperature sensor, but I assume that it works well enough.


Of course, I immediately jumped ahead into the middle of the instructions. Auber had sent me a new kind of resistive temperature sensor, which I just HAD to install first. You can see the large beige boiler temperature sensor in the picture on the left. A similar sensor for steam temperature has already been removed in this picture.

The new temperature sensor screws into a mounting hole underneath this old sensor (which was mysteriously empty before). Take a look how clean and brassy the boiler is. Mass is your friend when making espresso, and brass is very heavy; much heavier than a cheaper aluminum broiler.


Next up, I had to rebuild the entire wiring harness. This picture shows the result right before tying up all of the wires.

In the right hand side of the picture, you can see the new controller wires as they thread through the hole behind the steam wand. Notice also that the original thermostat is completely disconnected.


Connecting up the PID requires pushing all of the wires through the back of the extruded aluminum carrier case, connecting to the PID and then replacing the endcaps. Finally, you attach the controller to the coffee machine via some 3M tape, which looks hokey, but is actually quite reliable.


And here is how it looks when it is done...