Nuova Simonelli Oscar II: water after pause in use for more than 8 hours

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#1: Post by partick »

Hi there, this is my first time posting here. I've recently upgraded from a Sunbeam EM6910 to a NS Oscar II, the machine so far has been an amazing improvement and I want to know more about it to take the best care of it I can.

I've read through the manual, and in one part it mentions;
NOTE: At the start of the day's activities and in any case, if there are any pauses of more than 8 hours, then it is necessary to change 100% of the water in the circuits, using the relevant dispensers
What exactly does this mean, and why would this be of concern exactly? Do they mean to flush out the water from the boiler by running the steam wand, or flushing the wand and brew head slightly before use if it's been a while? Seems that there would be breaks of 8 hours or more through daily use, so I'm wondering what exactly this means.


#2: Post by checkwhatsleft »

I think what it says was reload with fresh water if it's turn on for longer than 8 hours, and I assume that no one would like to drink hot water that's been heated for that many hours, that's interpretation of this.

partick (original poster)

#3: Post by partick (original poster) »

I see, but how would I dispense hot water? I guess that would mean running the brew heat and steam wand a bit to remove any heat exhanger water and some boiler water?


#4: Post by checkwhatsleft »

There are two ways to empty the boiler of Oscar II, one was at the left side of the boiler that has a nut with screw glue sealed, it is quite difficulty to remove it, another one is easier, heat up boiler until its heating elements stop to heat, turn off the machine, unplug the power cord, turn the machine left side down, that makes boiler vertically up, and with the pressure from steam and gravity, remove the steam tip and it pours like flood, really quick way to empty boiler.

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#5: Post by Jeff »

While it is valuable to periodically draw water from the steam boiler to prevent the mineral concentration from rising and causing scale, draining the boiler daily seems excessive for a home user. Draining the boiler "dry" sounds very strange to me. A cup (250 mL) every day or even once a week is probably fine, assuming you're starting with "non-scaling" water. This would be through the hot-water tap. There's a couple threads on managing steam-boiler concentration in the Water sub-forum (which I can't immediately find). Boiler water in an HX does not end up in your coffee, just out the hot-water tap (often not tasty, as concentrated) and steam ("distilled")

Here it is: Using hot water tap to manage steam boiler water concentration

The HX probably has a couple hundred mL, gets fresh water with every shot, circulates, and probably needs no special draining. Your "flush" to manage temperature is probably enough.


#6: Post by caeffe replying to Jeff »

Jeff - unfortunately, in the case of the NS Oscar (I or II) there is no hot water tap. Because of this, it is difficult to manage the boiler water concentration via a hot water tap. Probably one way is to use good non-scaling, non-corrosive water - something like RPavlis water.
LMWDP #162

partick (original poster)

#7: Post by partick (original poster) »

Hmm turning the machine doesn't sound as bad as taking the side off, maybe i'll try both to see what I can do semi-regularly... At least if the stale water is only powering the ste wand this isn't a huge issue to worry about fairly regularly right? Other than mineral build up?

I've heard of rpavlis's recipe and I think I'll stick to that to avoid descaling


#8: Post by checkwhatsleft »

Turn the machine left side down is the way for Oscar II to descale the boiler, however, as long as you don't forget to turn it off within reasonable hours, I don't think that empty it is necessary, but you learned how to descale the Oscar II, that method works on Oscar I and Musica as well.

partick (original poster)

#9: Post by partick (original poster) »

Ah I see, thats great to hear. So just if I happen to leave it on for a very long time I should probably empty the boiler, or empty out a lot of water just to freshen the water inside?

Do you know if using a wifi plug is a good idea with a machine like this? I've heard something about needing a vacuum breaker, but i'm not really sure.


#10: Post by checkwhatsleft »

Oscar II is 10A amp draw machine, there is no need for fancy breaker anyway, pull cup of blank shots if you accidentally forgot to turn it off for hours let, let the fresh water goes through the exchanger chamber and empty the steam pressure once the heating elements indicate is no longer on and off, as long as you don't that often, no worries.