I'm about to throw Silvia out the window! - Page 2

[tcampbells]

HB - Thanks for point that out. I stand corrected.
Though I still feel it shouldn't be necessary to remove it to find a fine enough grind to get a good shot on a Silvia.

[Brownie]

Measure the flow in the return line using a pyrex cup while pumping with a blind filter. With a stop watch, time how long it takes to go from the 2 oz mark to the 6 oz mark or 4 oz to 8 oz etc, etc. You'll come up with 4 ounces in "X" seconds. "X" should be between 27 and 28 seconds. Adjust the OPV as necessary to get this time.

Hi, Does the above go for all models? My Silvia is from 12 06. I just tried this, and unfortunately i reached exactly 40 seconds...what way should I adjust...and how many rounds should i adjust?

Thank you!

Update: Now i turned it counterclockwise (loosened?) - 1½ turn - and now i reach the 4oz in 29 sec!

[japa_fi]

I have the new silvia mode. I've tested measuring OPV by the volume of water coming from the overflow tube with a blind filter. Then later I got a hold of real portafilter pressure gauge. All I can say is: Don't trust the overflow water volume measure method. Also when measuring with PF pressure gauge one should take it to account that when there is actual liquid flow trough the puck, the pump can produce less pressure.

I did my experiment by opening the pressure PF valve just enough to have flow that was approx 2 oz in 25 secs. (Aimed to 30-40gr of liquid). Looking at the needle and it looked to average at about 9 bars. The pressure without any flow was aprox 10-10.5 bars. According to overflow volume measuring method my OPV would have been set at about 7.5 bars. I ended up not adjusting.

[erics]

The "overflow method" of determining Silvia's brew pressure is based on this pump capacity curve:

The solid "curve" represents a production average whereas the long dashes and short dashes represent highs and lows off the production line but still acceptable to be "sent out the door". Most of the pump manufacturers that have their products installed in machines discussed in this forum report performance in the same manner.

Adjusting an OPV such that you achieve 3.67 ounces in 25 seconds (4 ounces in 27-28 seconds) has its faults as the pressure at the pump can be anywhere from ~ 7.0 bar to ~10.5 bar. Measuring with a typical portafilter pressure gage also leaves room for improvement. Most portafilter pressure gages (the Scace II Thermofilter excepted) have NO PEDIGREE, i.e. the manufacturer of the gage didn't even want to put his name on it. The pressure pulsations are SOMEWHAT damped out by a small orifice screwed INTO the gage connection rather than supplying a reputable and traceable gage filled with glycerin for $ "X" additional.

I'd say that the best portafilter pressure gage is one you construct yourself (if possible) with an adjustable flow valve such that you can vary the flow to your liking and check/adjust the OPV similarly.

[Brownie]

Damn guys...do you want a laugh ...on my behalf!?

It turns out i read on my "pyrex"/Bodum cup wrong. I read "flour oz" and not "US flour oz" which are about 1½ wrong ...i will correct this....and my 40 seconds might just turn out ok after all...

Update: Now i ended up tightening 1/4 round. I now hit 29 sec...