Valentina brew pressure adjustment - Page 3

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AndyS

#21: Post by AndyS »

Bradley Allen wrote: First, I want to double confirm that the OPV valve is 'lefty loosey, righty tighty' (left lowers the pressure, right increases the pressure). I've cranked to the left and to the right, and either way this is what happens:

The needle on the manometer rises to 1.2, then it slowly falls to just under 1.0, then the green light switches on, then the needle rises to 1.2, and then it slowly falls again. Rinse, repeat.
The manometer readings that you're looking at are boiler pressure (AKA "service boiler pressure.") Service boiler pressure is controlled by the pressurestat.

The OPV valve is a different animal. It limits extraction pressure in the heat exchanger/brew head loop. You can't control the service boiler pressure with the OPV. So stop trying. :-)
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

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HB
Admin

#22: Post by HB »

Don't confuse brew pressure (adjust OPV / expansion valve) and boiler pressure (adjust pressurestat). Valentina / Levetta doesn't have a brew pressure gauge, you will need a gauge attached to the portafilter.

PS: Counter-clockwise (left) = looser = more water escapes = lower brew pressure.
Dan Kehn

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shadowfax

#23: Post by shadowfax »

that's the BREW pressure adjustment, not the BOILER pressure adjustment, Einstein!

:p

You need to be putting a cup to the pressure runoff (which is the OTHER tube feeding into the rear reservoir, putting a blind filter in, and running the pump for 30 seconds (remember, 30 seconds AFTER the preinfusion, you can tell when preinfusion ends, the pump will bog), and checking the volume that comes out. anything less than 2 oz, and you need to loosen (counter-clockwise). anything over 2.5, and you need to tighten (clockwise).

You will have to locate your Sirai Pressurestat if you want to adjust boiler pressure. Why would you? it's set just about right. anything less than .9, and you will get crap steam. anything more than 1.2 and you will have no time to pause after flushing. If you try to make the window smaller (say .9-1.0), your boiler cycles will be very short and the heating element will turn on and off, on and off, on and off, a WHOLE LOT. this will ultimately wear your pressurestat and heating element out much faster.

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cannonfodder
Team HB

#24: Post by cannonfodder »

Bradley Allen wrote:The needle on the manometer rises to 1.2, then it slowly falls to just under 1.0, then the green light switches on, then the needle rises to 1.2, and then it slowly falls again. Rinse, repeat.
Sounds like you are adjusting the P-Stat (boiler temperature adjustment). The OPV should have no interaction with your pressure stat which is what it sounds like you are describing. The OPV only comes into play when the pump is pressurizing to brew.
Dave Stephens

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cannonfodder
Team HB

#25: Post by cannonfodder »

I did not see the next page before I posted, sorry for the redundancy. :oops:
Dave Stephens

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shadowfax

#26: Post by shadowfax » replying to cannonfodder »

Haha, poor Bradley, we hit him 3 in a row across 5 minutes, and now you... That's pretty funny.

It's OK, Bradley, we've all gotten our variables mixed up before... gotta be able to laugh about it ;)

Bradley Allen

#27: Post by Bradley Allen » replying to shadowfax »

Oh, I'm laughing it up. And will be for years. Via the power of the Internet, future generations will be able to look back on this time as: "Oh, that's when that no-nuthin' Bradley Allen guy first looked under the hood of an espresso machine... and was frightened by his own distorted reflection in the boiler". :-)

Thanks for setting me straight, folks. Sometimes a dog pile is the best way to learn. Seriously. I appreciate it.

ECM Manufacture: @ecmespresso #weliveespresso
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shadowfax

#28: Post by shadowfax »

I wish I could see my reflection in my boiler...

Bradley Allen

#29: Post by Bradley Allen » replying to shadowfax »

It was a joke. I can't really see my reflection in it. In other words, "afraid of nothing".

Bradley Allen

#30: Post by Bradley Allen »

shadowfax wrote:You need to be putting a cup to the pressure runoff (which is the OTHER tube feeding into the rear reservoir, putting a blind filter in, and running the pump for 30 seconds (remember, 30 seconds AFTER the preinfusion, you can tell when preinfusion ends, the pump will bog), and checking the volume that comes out. anything less than 2 oz, and you need to loosen (counter-clockwise). anything over 2.5, and you need to tighten (clockwise).
Okay. I had to go out of town.. now I'm back. The machine is still apart and I have time to play.

Again. I'm confused. The pressure runoff is the rubber tube that's connected to the OPV, and normally goes into the rear reservoir, right? Okay. Fine. I pulled that out and put a cup underneath it. I opened the lever, let it run for 30 seconds after pre-infusion and no water came out of it. Weird.

So back to doing what I think I think I should be doing (PLEASE correct me in detail how I'm doing it wrong)...

I have a blank portafilter in the group. And a liquid measuring cup under where the waste water comes out (below the solenoid in the lower group).

I open the lever. I let it run for 30 secs. after pre-infusion. Then I close the lever and measure the water in the measuring cup.

It comes out to about 1.5 oz. of water. I turn the OPV counter-clockwise some more. Rinse. Repeat. It's still under 2 oz. of water.

I think I'm going insane.
shadowfax wrote:You will have to locate your Sirai Pressurestat if you want to adjust boiler pressure. Why would you? it's set just about right. anything less than .9, and you will get crap steam. anything more than 1.2 and you will have no time to pause after flushing. If you try to make the window smaller (say .9-1.0), your boiler cycles will be very short and the heating element will turn on and off, on and off, on and off, a WHOLE LOT. this will ultimately wear your pressurestat and heating element out much faster.
I didn't try adjusting the Sirai Pressurestat. All I did was loosen the hex screw that mounted it to the machine so I could get at the OPV behind it. It's cycling between .9 - 1.2 (which, as you say, should be normal). It just appears to be doing it a WHOLE LOT. I'm not sure what's up with that.