I am planning to buy a new european nuova simonelli oscar . The dealer from ebay told me that the new models dont have sirai pressurestat and solenoid and they can plugged in a timer . He also told me that the machine has prefixed pressure and if i had a chance to change pressure(he told me that i cant adjust the pressure ) it will surely be worst result.Can you tell me ,looking the image , what is the difference from the oscars you had seen ? I need expert advise. Does it worth without the professional sirai pressurestat and anything else that is missing? Does anybody had tested oscar and brewtus 3 and how much difference they have in espresso quality only?

It looks like a cost-cutting measure that they have gone away from the Sirai P-Stat...I owned an Oscar before my current machine (the Brewtus 3R), it had the Sirai, one thing about them is they were noisier
in operation (loud click when cycling the P-Stat). That may be another reason they changed from it. It looks like they may have added a Vacuum Breaker below the P-Stat on the model in your picture as that is not familiar looking to me.

Oscar is a more capable steaming machine than the Brewtus, so if you do allot of steaming that would be a plus. Of course being an HX you will have to understand the need for temp surfing to get the type of brew temp you desire out of the machine.

In the models they were selling here (I bought mine new) the boiler pressure was set Low and the brew pressure is Too High! It takes quite a bit of plumbing/modification to overcome this...here is a thread that will give you the kind of information you need: Nuova Simonelli "newer" Oscar - how to lower the brew pressure?

The top photo shows the "over pressure relief valve" and although it does not have a hex, I decreased the tension to lower the opening of the valve, not a proper way to control brew pressure by any means...the rest of the posts describe the proper modification to do so.

I own an Oscar that has the Sirai but no breaker. I have the machine on a timer so I just have to crack the steam valve when I wake up in the morning and then wait a few minutes, no big deal. Yes it's a loud pstat but you get used to it and in fact I don't even notice it anymore. I installed a proper OPV that routes excess cold water back to the tank. You can always just loosen the pressure relieve nut as a quick fix but that's on the hot side and losing the extra hot water may affect your brew temperature profile. Adjusting the boiler pressure is easy

Ok because i am seeing here a learning curve for all of these stuff . I have a silvia for a year now and i thought that i know the basics . I am sure in the hunting of the god espresso . For now is it needed to buy ''proper opv'' or to think that my pressurestat is not commercial and i have to change it because i dont know how exactly all these work? Whats the difference between the pressurestat and the opv ? Why i need to change them ? I am confused now ,if i buy a brewtus i will avoid all these upgrades?

I would say you won't need to change out the pressurestat, you just may need to adjust it from the factory setting.

The OPV would need to be addressed if these machines are still well above 9.0 bar pressure at the portafilter, as I imagine they still are. This would require the type of modifications shown in the Topic I highlighted for you.

The two machines are worlds apart...the Brewtus being an E-61 design, with PID and dual boilers. The Oscar is certainly capable of pulling nice shots once the HX flush is understood and the brew pressure is addressed. The Brewtus is a substantial upgrade (and the OPV is indeed set correctly & adjustable with a gauge right on the front of the machine)...and depending on the price difference there in Greece, you may want to consider it or another variety of espresso machine. If your only needs are for a straight espresso (no milk drinks) you really have no need for a dual boiler machine, and there are less expensive, temp stable, single boiler espresso machines to consider.

CUBANERO wrote:I am planning to buy a new european nuova simonelli oscar . The dealer from ebay told me that the new models dont have sirai pressurestat and solenoid and they can plugged in a timer . He also told me that the machine has prefixed pressure and if i had a chance to change pressure(he told me that i cant adjust the pressure ) it will surely be worst result.Can you tell me ,looking the image , what is the difference from the oscars you had seen ? I need expert advise. Does it worth without the professional sirai pressurestat

I don't own a Oscar but I have researched it a bit, can or can't be plugged into a timer, to plug into a timer would require a vacuum breaker I can't see one on the image. Sirai pressurestat I am not sure if the Sirai is fitted for all markets I think it was originally fitted to cope with 110V current draw, it is fitted to Australian machines(240v) but I am not sure all markets get it, but I could be wrong. Non adjustable brew pressure is standard Oscar.
This does not look like a new model Oscar to me, but I'm no Oscar expert.

CUBANERO wrote:Whats the difference between the pressurestat and the opv ? Why i need to change them ?

Pressurestat = steam boiler pressure regulation. Over-pressure valve (OPV) = regulation of maximum brew pressure (see I still don't get it: Why adjust the OPV? for much longer explanation).

For the sake of completeness, there are other espresso machines with vibratory pumps that don't have OPVs. Although many home baristas prefer espresso machines with adjustable brew pressure because it allows for lower-pressure ristrettos, the Elektra Semiautomatica, Salvatore One Black, and Olympic Maximatic are three other well-known models that do not include an OPV. You can retrofit one; Chris' Coffee sells a high-quality expansion valve for this purpose.

This opv isnt adjustable for sure? What is the difference with the pid oscar here?

Project: PID NS Oscar: Result: Modded now Graphing/Learning

He changed the opv or he adjusted it? This opv looks the same with mine . Mine also has a vacuum breaker or not? The dealer told that i have no problem to put it on a timer .

Yes, put it on a timer. But, once everything is warmed up you need to open the steam valve for a quick second to release false pressure in the system. You'll notice the boiler light will turn on. Wait a few minutes before pulling your first shot. You only have "bleed" the steam pressure once each time you turn on the machine, not each time you pull a shot. The vacuum breaker we speak of would fix this. I don't have a vacuum breaker as I don't mind performing this small, easy step.