Rancilio Silvia - Temperature dropping rapidly while pulling shot

September 15th, 2015, 7:57 am

Hey all,

I've recently moved and ever since I unpacked my Rancilio Silvia, she has been behaving weirdly.
Before packing her, I emptied her tank. When I set my machine up in the new place, I wanted to pull a shot, so I filled a cup with water from the grouphead to get its temperature up. However, the temperature dropped rapidly from 95°C to ~60°C before the Cappuccino Cup was full.

Has anyone experienced this kind of behavior?
Do you have any idea why the machine is behaving this way, and how it can be fixed?

Thank you all in advance.

#2: Post by **LukeFlynn** » September 15th, 2015, 8:15 am

While you are pulling water through the group, you are replenishing the water with cold water from the tank, therefore the temperature reacts to the cold water. How is the taste?

#3: Post by HB » September 15th, 2015, 8:27 am

Midnight_Marauder wrote:I wanted to pull a shot, so I filled a cup with water from the grouphead to get its temperature up. However, the temperature dropped rapidly from 95°C to ~60°C before the Cappuccino Cup was full.

GIven its boiler volume is only ~10 ounces, what you describe sounds normal. If you're interested in cutting down warmup time by heating the group, I would not draw more than 2-3 ounces at a time. See Cheating Miss Silvia for more hints.

September 15th, 2015, 8:51 am

Thanks for the answers!

The thing is, I've had my Silvia for three years now, so I am pretty familiar with her usual behavior. I know that the water did not cool down that rapidly before I moved her.

#5: Post by HB » September 15th, 2015, 9:01 am

That's one of the problems with PIDs... they give you insight into the instability of the system, potentially leading to needless worry since in the majority of cases, that instability has no practical impact. If you're concerned about brew temperature consistency, ignore the PID readout and measure at the grouphead, which is what matters. If it's just a matter of an "espresso imponderable", I'll go with the jostle of a move affecting the quality of the PID sensor's contact, scale, or espresso gremlins.

LukeFlynn wrote:How is the taste?

Good point. Once it's all warmed up, does the espresso taste the same as always?

September 15th, 2015, 9:19 am

That doesn't sound right. That's way too much of a drop.

My guess is that there is air trapped in the top of the boiler. I don't know which PID you are using, but turn the machine on from cold and then immediately run the pump with the grouphead off (so the pump runs but water goes nowhere). Then open up the steam wand until there is a continuous stream of water.

Let us know how it goes, please.

September 15th, 2015, 9:30 am

baldheadracing wrote:That doesn't sound right. That's way too much of a drop.

My guess is that there is air trapped in the top of the boiler. I don't know which PID you are using, but turn the machine on from cold and then immediately run the pump with the grouphead off (so the pump runs but water goes nowhere). Then open up the steam wand until there is a continuous stream of water.

Thanks for the tip, I'll definitely try that as soon as I am home. I'll let you know how it played out.

LukeFlynn wrote:While you are pulling water through the group, you are replenishing the water with cold water from the tank, therefore the temperature reacts to the cold water. How is the taste?

I haven't actually pulled a shot yet, as I was in a hurry and got frustrated about the unexpected temperature drop

September 15th, 2015, 10:17 am

baldheadracing wrote:My guess is that there is air trapped in the top of the boiler.

There is always air at the top of a SBDU espresso machine boiler be it Silvia or other.

September 15th, 2015, 11:37 am

FYI, I pulled out my Silvia after my reply this morning.

PID temp from (v1) thermowell at top of boiler, no offset:
102 C - idle, 40 minute warm-up
77 C - after drawing 170ml of water (full cappuccino cup) through the grouphead
92 C - at end of making a 28g double

So I had a 25C drop and you had a 35C drop.
The steam wand outlet is the highest point of the Silvia boiler assembly. If the machine is on a level surface and air is purged from the wand, then it is impossible for air to be in the system. Keep in mind that there is no vacuum breaker in a Silvia so the (properly running) system is sealed.

#10: Post by **kmw** » September 15th, 2015, 11:49 am

If you emptied her while she was hot, maybe there was scale or build up generated?