My Silvia is about 2 years old, and has the newer, adjustable OPV. I have the gauge from 1st Line. I find that if I adjust the valve until the gauge reads around 10 bar, although brew performance seems fine, the machine cannot generate sufficient steam. Returning the setting to about 11 bar on the gauge corrects the problem. Maybe the gauge needs calibration? On the other hand, I have read that the Silvia ships with the OPV at 11 bar. Anyway, if you go too low, you kill the steam.


PS added by moderator: Split from Adjusting Rancilio Silvia brew pressure (OPV).

rickrobin wrote:I find that if I adjust the valve until the gauge reads around 10 bar, although brew performance seems fine, the machine cannot generate sufficient steam. Returning the setting to about 11 bar on the gauge corrects the problem.

I don't see how the OPV setting for brew pressure and steam performance could be related.

HB wrote:I don't see how the OPV setting for brew pressure and steam performance could be related.

I don't either, but there it is. I would guess that the OPV senses boiler pressure, and that setting it too low causes it to open before there is sufficient steaming pressure. Unless the valve, or a T'stat, got kacked in the process of my efforts.

Actually, I've had to dial it up to 11.5 to restore full steaming capability. Shots are very good. So it seems like there is a threshold beyond which the OPV is ineffective on brew pressure, but begins to strangle steaming performance. With my machine and gauge, anyway, that threshold is 11.5 bar.

Rick - here is a hydraulic diagram and some nominal flows for Silvia. This shows the old style OPV but the only change is that you can adjust the amount of spring compression internal to the OPV with the newer style.



The steam thermostat on Silvia shuts off the heating element at AROUND 300 F which would correspond to around 52-53 psi or ~ 3.60 bar.

As Dan said (and you agreed), there is no relationship between steaming performance and OPV setpoint. A nice STARTING point on Silvia would be 9.50 bar with the blind filter. I can't imagine what would cause the problem you are seeing but I'll give it a little thought.

Thanks for the help, guys - much appreciated. Yeah, apparently it was just coincidental that the steam was temporarily OK after I adjusted the valve up. I put it back to 9.5. Now the question is, what's happening with the steam? The stat isn't shorted. Maybe it went out of adjustment? although the machine gets way hot physically with the steam switch on; but there's only strong steam for a few seconds before it becomes anemic. I just descaled a few weeks ago. Guess I'll try doing it again. One thing I notice is that the plastic insulator on the wire clip that connects to the boiler is burnt to a crisp. Been that way forever though. ?

I think it's the steaming stat. The steam is only 150 degrees. After a few seconds I can hold my hand in it. S

I would proceed with a little bit of caution here. How old is Silvia? Have you removed the steam tip and checked for any obstructions?

Silvia responds very well to a PID installation - see here: http://www.home-barista.com/espre...out-pid-t4691.html

I agree that the plastic terminal covers get brittle over time and sometimes have a tint of "crema" on them BUT "burnt to a crisp" - ?? Some pics would help.

It's about 2 years old.

That is a WAAY OVERHEATED terminal. I suggest you disconnect, remove the plastic, and GENTLY tighten the fit of the female spade to the heating element terminal.

Although I think you said it has been that way for a while, the additional resistance due to a poor connection is equivalent to putting a resistor in series with the heating element and this would certainly be a contributor to less than adequate steaming power.