Nuova Simonelli Oscar steam and temperature problems - Page 2

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dlemon (original poster)
Posts: 26
Joined: 11 years ago

#11: Post by dlemon (original poster) »

UPDATE:
- Installed a new Sirai pstat. Deadband issues gone and able to get a shot pulled at about 204 f.
- I've got the boiler pressure at 1.1 bar, but I'm not satisfied yet with the temps of shots pulled after the first shot. Shot's pulled after the machine has been idle for 5-10 minutes are hitting between 200-205 f with a short cooling flush. If I proceed to make another shot immediately after grinding, dosing, tamping, and NO cooling flush temps are in the 190's f.
- Here's my hunch - the expansion valve is dumping a lot of water into the drip tray. I did try to adjust the valve, though I know it's not a true OPV just to experiment. I've tightened it back down, but didn't make a difference. I'm going to start a new thread with a video for this new problem.

FinnLight
Posts: 97
Joined: 11 years ago

#12: Post by FinnLight »

No, you need to raise pressure. The oscar hx has less thermal mass than many other prosumer hx's out there. To compensate this you need to run it at about 1.5bar (sealevel) and that is how they come shipped. This is why your recovery is not sufficient.

The newer models at least in Europe do not ship with Sirai but a Campini pressurestat. Sirai is much more robust but has about the same dead band. Also, you should not adjust the campini, but Sirai you can adjust.

-Mikko

dlemon (original poster)
Posts: 26
Joined: 11 years ago

#13: Post by dlemon (original poster) »

Thanks FinnLight, I was cautious raising the pressure - seeing that most HX users have their's set at 1.1 or 1.2 + where I live I'm at over 5000ft above sea level.

I'm still taking it up slowly, (adjust pstat, then use for a day) but seen some improvement in rebound time. Next time I check temps, I'll probably use it together with my brew pressure gauge that has a needle valve to control flow. I was using my thermocouple while actually brewing, placed inside the portafilter but was getting inconsistent results. It seemed like the brew pressure was forcing the thermocouple bead into the coffee puck.

- Daran

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