Oscar Boiler Pressure

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fastbikes16
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Joined: 15 years ago

#1: Post by fastbikes16 »

I have been a long time lurker here and am finally posting:) I have recently upgraded to a NS oscar from my previous machine, which I had never attempted to adjust the brew temp on. I am working on dialing in my Oscar, but since it has no gauge, I am measuring pressure. My problem is that it seems like the temp is WAY too low. The machine has the sirai pstat and I have turned it about 4 full turns and the temp is only up to about 180. I am measuring this using my steaming thermometer in a styrofoam cup. Is there someting wrong with what I am doing? I am just woried that I will turn the Pstat too far up.

Also, The machine is used, so I guess it is possible that the previous owner had turned the pressure way down, but I don't know for sure.

Any help is greatly appreciated!

Thanks,

Scott
LMWDP #306

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HB
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#2: Post by HB »

You'll need a pressure gauge to adjust the boiler pressure. Some people adapt a tire pressure gauge to the steam arm using brake hose and hose clamps. It's a bit MacGyverish, but works. Or you use bits of plumbing to adapt a proper pressure gauge to the boiler fitting of your choice. See Trouble adjusting pressurestat of Nuova Simonelli Oscar, Proper Adjustment for Oscar's Pressurestat, or Problems with Nuovo Simonelli Oscar for more details.
Dan Kehn

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fastbikes16 (original poster)
Posts: 11
Joined: 15 years ago

#3: Post by fastbikes16 (original poster) »

SO I finally got to the hardware store and set up a gauge on the steam valve. I measured the pressure there at just below 20psi, or around 1.3 bar. This seems high to me, yet the shots still taste sour, and the temp still measures around 180-190 at the group. I thought that maybe it could be a scale buildup in the hx, but I just recently descaled it. Is it possible that it could need a descale again, because I bought it used?

I also thought it worth mentioning that I am fully aware that my grinder is inadequate, but the wallet won't support the vario ... yet :lol: However, I don't think the grinder is causing the sourness, because I am getting shots within the 22-27 sec range.

Also, I am using Black Cat that is a week and a half old, with a 14-15g dose.

Thanks again,

Scott
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#4: Post by HB »

fastbikes16 wrote:This seems high to me, yet the shots still taste sour, and the temp still measures around 180-190 at the group.
If your measurements are accurate, you're either flushing too long or the HX is heavily scaled. As for the sourness, be aware that can be caused by channeling too, not just temperature.
fastbikes16 wrote:However, I don't think the grinder is causing the sourness, because I am getting shots within the 22-27 sec range.
You don't mention what grinder you're using, but a poor grinder will produce grounds that extract unevenly. Common signs of this unevenness are thin, blond, sour shots.
Dan Kehn

fastbikes16 (original poster)
Posts: 11
Joined: 15 years ago

#5: Post by fastbikes16 (original poster) »

yes, that makes sense now that I think about it. I am using a Capresso Infinity, as it is all i can convince my parents that I need, for the time being 8) I am hoping to upgrade to a vario in a while.

I guess my next plan of action will be to descale the HX again, and save up some money on a grinder.

Because my temp is so low, should I descale more than once?

Thanks again,

Scott
LMWDP #306