The safety pressure valve on my Oscar sprung a leak so I ordered a new one. After installing it, I tried to pull a shot an pressure began to release from the new valve in spurts. I was puzzled, how could pressure from the group head affect pressure in the boiler. I took apart the three way valve and gave it a thorough cleaning, this did not help. The only conclusion I can come to is that there is a crack in the HX tubing inside the boiler that is causing a pressure leak into the boiler.

Does anyone have any other items I could check?
Where can I get a new boiler? I have searched and called several places and so far no luck. I found one place online with one for $427 which included a bunch of fittings I don't need. At that price I would rather salvage from a used/broken one. I only need the boiler.

Thanks for your help.

I realized the fitting on the boiler were standard 1/4 inch just like my air compressor. I hooked up the compressor to the hx tube and plugged the other end. I went up to 125 PSI, no leaks. The boiler appears to be fine. I am ordering 07300370 retaining valve body and 01000090 retaining valve. This is the valve between fresh water entering the HX/group and water recirculated through the HX from the group. If this valve fails, group head pressure can leak into the fresh water supply to the boiler. The parts are only $9.40. Wish me luck.

How about the 2-way solenoid valve?

Marcio is certainly correct - how about checking/disassembling your boiler fill solenoid valve - p/n 04100006.

A boiler fill solenoid valve that has NOT returned to the closed state (or has a leak) is your likely culprit. You will also need to syphon out some water from the boiler such that the fill level is ABOUT 2/3 after repairs are made.

I pulled the switch off the 2-way solenoid and could not figure out how to get inside the valve to check it, are they serviceable? Maybe I should just order one and be done with it.

What do you mean about emptying it to 2/3. It is completely empty now. Wont the boiler just automatically fill up to the proper level once I fire it up?

Thank you very much for you help Carneiro and erics. I had thought about the 2 way but just assumed it was ok because solenoid valves are supposed to be reliable. Thanks for putting me on the right track.

erics wrote:Marcio is certainly correct - how about checking/disassembling your boiler fill solenoid valve - p/n 04100006.

A boiler fill solenoid valve that has NOT returned to the closed state (or has a leak) is your likely culprit. You will also need to syphon out some water from the boiler such that the fill level is ABOUT 2/3 after repairs are made.

So the default state of the solenoid valve is shut? I aired it up to 60 psi from the fill side and air went flying through. Looks like I have the culprit.

The default is closed. Remove the solenoid coil and you will see the disassembly procedure. Takes pics for those who follow in your footsteps.

If the boiler is empty, disconnect the heating element before you start to fill.

Wont the boiler just automatically fill up to the proper level once I fire it up?

Energizing a heating element with an empty boiler is simply asking for trouble especially if the vibration pump fails to take suction immediately and there is a delay in filling the boiler for whatever reason(s).

I was not sure how to take the 2 way valve apart. I just cranked on the top silver part using channel locks and and a rag around the cylinder so I wouldn't mark it up too bad.

Here is the whole unit together:


Here is the unit apart:

Notice the compressor fitting on the valve.

The valve looked to be in pretty good condition. The spring is surprisingly weak, it is similar to one found in a small clickable ball point pen.

I finally figure it out! It was the retention valve. Here is a picture of the new part:


Looks like this may be a somewhat common problem with the Oscar:
Nuova Simonelli Oscar with brewing trouble

If anyone needs a 2 way valve, let me know, I have a spare.

Now I have a problem with wet steam. Water level sensor seems fine so not sure what to do next. Maybe turn up the pressurestat a little?

I found the answer to my steam problem in broken English here:
http://www.elektros.it/en/tips_and_tricks.html

It appears filling the boiler before turning on the Oscar is not the way to go. The Oscar's heating element will not turn on until the boiler is filled so you can't burn out the heating element. Filling the boiler manually appears to throw off the water level sensor.

Excited to have my Oscar back, the steam that comes out of the wand now is ridiculous. This thing has never worked this well. I also replaced the crumbling foam insulation with fiberglass. Here is a picture:

On a side note I will miss the La Pavoni Europiccola Millenium I have been borrowing. I broke the plastic piston on that one and replaced it with a brass one, my friend got an upgrade. That machine is a lot easier to fix than the Oscar. Some of the shots I pulled on that thing were the best I have ever had.