If the machine heats up to brew / steam temperature and water flows, it's hard to say no to Silvia at 235 USD. Silvia is a simple machine as you can see from this
parts diagram, so should something need fixing, you can probably handle it yourself. Below are the things I would look for, starting from the pump and moving towards the group:
- Make an espresso.
If you are feeling lucky and the owner doesn't mind, try making a few shots. Temperature management with Silvia is a pain, but you shouldn't have any trouble dialing in the grind given your regular gear at work (I offer some hints and links in my Rancilio Silvia Flash Review). Producing even a modestly decent shot would rule out any serious problems. If the owner isn't willing, then move to the things to check that follow.
- Check the pump with and without resistance.
The chart below shows the flow rate for a typical Ulka pump (e.g., EP5). Silvia has no gicleur, so the flow rate should be around 650mls with no resistance. To check under load, ideally use a portafilter pressure gauge (the La Marzocco's will fit, though it is tight), or insert a portafilter with blind basket and measure the outflow from the second (shorter) tube that drains into the tank. That's the overflow tube for the over-pressure valve (OPV) and it should open in the 8-11 bar range (the setting varies a lot from Silvia to Silvia). Anywhere in 100-300ml / minute range is technically "normal". If you see no flow, the expansion valve is stuck shut or the pump isn't reaching enough pressure. If you see a much greater flow, the spring in the OPV has gotten tired over the years.
- Check the brew and steam temperature.
Allow the machine to warm up preferably for a half-hour or more, then draw water from the boiler at the top of the heating element cycle (when the light has just turned off). Using a thermometer and Styrofoam cup as explained in My Espresso is Cold! you should be able to measure at least 190F from the group. Flick on the steam switch and wait a few minutes. If it produces steam, you're off to the next item.
- Check the group cleanliness.
Sorry, this should be the first thing. If you can't remove the dispersion screen screw, it's likely the owner hasn't maintained the machine well. If you're lucky, it will unscrew easily and you've gotten a very good deal. Assuming the pump and boiler check out, it's still a deal after a good cleaning.
- The great unknown - scale.
If your region has soft water, this may be unnecessary. Horror stories about scale buildup abound, but if the flow rates are good, chances are the buildup isn't too bad. I can't think of a non-intrusive way of checking Silvia for scale. It would be good news if the owner could explain their maintenance regime (e.g., "I use CleanCaf (or similar descaler / cleaner) once a month to remove scale from the boiler.").
Be aware that the heating element is welded to the boiler, which adds considerable cost to an otherwise inexpensive repair. Even so, at the price you quoted, you can afford to spend some repair money and still come out way ahead. Of course that begs the question... how are you going to get along with Silvia at home when you use a two-group Linea at work?
(image courtesy of Ulka S.p.A.)
