ila Senior Member Joined: 24 May 2012 Posts: 12 Location: Italy Expertise: I love coffee
Posted Sun Oct 28, 2012, 10:25am Subject: Opv on my Rancilio Silvia
Hello everyone, I have a Rancilio Silvia (year 2005) and bringing it to the service center for a check I was told that the expansion valve (OPV) is damaged. Honestly I have not repaired also because he asked me usd 150 for the repair. how do I know if it is broken? I checked with a manometer if the pressure is adjusted and seems to work for me.
Coffeenoobie Senior Member Joined: 11 Dec 2011 Posts: 2,320 Location: PNW Expertise: I like coffee
Espresso: N S Oscar Grinder: Vario W
Posted Sun Oct 28, 2012, 11:06am Subject: Re: Opv on my Rancilio Silvia
My understanding is if you have a 3 way valve I believe you can see water coming out of an OPV when you back flush because you are creating an over pressure situation.
Click Here (www.1st-line.com) NEWEST Feature: The overpressure valve (a.k.a. OPV) is now adjustable on our latest batch of new Silvias (started in February, 2007). The overpressure valve is normally set to 11 bar. However, if your grind is just right, the grind should only create 8-9 bar of resistance so the overpressure valve will never open.
Some customers want to change this to 8-9 bar. No coffee will come out of your grouphead if the coffee grind has a resiatance greater than the setting on the overpressure relief valve. You will need the V512 pressure gauge to asses the pressure. Please note this part is not returnable. In addition, if you break something while doing this, you will need to pay for the part and shipping. If you decide to return the machine with the broken part, we will deduct the charge for the part and labor from the credit.
You can increase the amount of excess water pressure (meaning make the valve open at less than 11 bar) by bringing out the OPV and tightening the nut against the valve (like show). Or, you can decrease the amount of excess water pressure (meaning make the valve open at more than 11 bar) by bringing the OPV into the valve after you loosen the nut next to the valve.
(note if yours is 2005 makes wonder if yours has the same OPV.)
Coffeenoobie
Buying advice: GRINDER GRINDER GRINDER. Don't cheap out on the grinder. My coffee treasure map... Click Here (maps.google.com)
ila Senior Member Joined: 24 May 2012 Posts: 12 Location: Italy Expertise: I love coffee
Posted Tue Oct 30, 2012, 7:05am Subject: Re: Opv on my Rancilio Silvia
I do not know how to explain the defect, but simply silvia does good coffee. I tried to regulate and lower blood pressure monitoring with a pressure gauge (8 bar), but the result does not change. The cause of the defect was told that depends on the valve (OPV) .
Posted Tue Oct 30, 2012, 9:24am Subject: Re: Opv on my Rancilio Silvia
The factory setting of the OPV is often higher than 8 bar on some machines - about 12 bar is normal is the machine is set up for coffee pods. It could be that the factory checked the pressure, found it was less than 12 bar and therefore told you the OPV was damaged.
Somewhere around 10 bar static pressure or 9 bar dynamic (i.e. with water flowing at about the right rate to brew espresso) is good, although you might prefer slightly lower. If you see water coming out when brewing and have a static pressure of around 8-10 bar, then the OPV is working! I guess you should also check it for leaks when running though.
Posted Tue Oct 30, 2012, 12:35pm Subject: Re: Opv on my Rancilio Silvia
Yeah, I know that - I said 9-10 bar in the rest of the post. But the factory setting on Gaggia Classics, and reportedly some Silvias, is about 12-13 bar so that they can use the pods properly. Adjusting it down to 9-10 bar would mean it differed from the factory settings, and might possibly get flagged up as out of spec, and reported as such.
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