Tuesday, February 13, 2018

Rancilio Silvia heating element failure

Loose thoughts by Bjorn Landfeldt


The Rancilio Silvia is a single boiler espresso machine with a small (300 ml) boiler volume. Water from the tank is sucked by the high pressure pump and then injected in the boiler to drive hot water out to the group head or steam wand. 

I bought my Silvia (version 4) about three years ago and to be frank, didn't worry too much about the instruction manual. In retrospect perhaps I should have......


The Silvia has delivered good espresso since I bought it even though as of late I have noticed a deterioration due to lack of proper cleaning. About a month ago, there was a bang followed by a little smoke rising up from the left side. I turned her off and opened the top but couldn't see anything that looked burned so I plugged her back in and turned her on. She heated up alright and I continued using her for a few more weeks. One morning though, the heater only managed to get the water lukewarm and the overheating safety fuse was not the issue. 

I measured the resistance over the thermostats which was close to 0 Ohm, but the reading over the two heating element terminals was not the healthy 64 Omh, but rather 1 MOhm or so.

Verdict, the heating element had blown.


I have purchased a new element and gasket (on its way in the mail) and in the mean time I have pulled her apart and cleaned her properly. The figure below shows the top of the boiler so it is clear which version I have.

I have seen on some forums that people take the entire machine apart to remove the boiler but this is not necessary. This is what I did. 

  1. Mark all connectors and corresponding leads and take photos to make sure things get back where they belong in the end
  2. Remove all leads
  3. unscrew copper pipe to the steam wand and loosen it from the steam valve so it can be moved up and to the side
  4. loosen the nut holding the heating element just a little so there is no problem unscrewing it when the boiler is removed
  5. loosen the nut to the three way valve from the boiler. I could not unscrew the valve here but it was OK
  6. unscrew the  boiler screws at the bottom using an allen key 
  7. lift up the boiler head and tip it on the side so the three way valve can be unscrewed

The bottom of the boiler was covered in the debris from the ceramic insulation inside the heating element and the element itself was deformed and not centred in the boiler anymore.

 This is what it looked like when I pulled it out.

Lesson learned.

I have come downstairs every morning and turned on the Silvia until it heats up and then opened the steam valve until there is only steam coming out. Then I have foamed my milk before turning off the steam heating and started making the espresso. What I have not done is to make sure that the boiler is full of water before the element gets hot. After some research I now realise that water can run back into the tank and the boiler becomes less than full which will expose the heater element to air inside. This will sooner or later result in the composition of a blog post.......

So, important rule: Always run the pump when you turn on the Silvia to make sure the boiler is full. The best thing would be to run water through the steam wand as the outlet here is on the top the boiler so it is sure to be full.

Having put her back together and tested her, I am a happy man again. Need to go out and get some fresh beans just, the machine was out of commission for a month or so and the beans I had in the grinder were, well... Not that good anymore.