Nuova Simonelli Oscar problem around the boiler

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ricky analog
Posts: 31
Joined: 9 years ago

#1: Post by ricky analog »

I was pulling a shot today and towards the end of the shot I could tell something was wrong. The pressure started to die and I heard noise from the machine over the sound of the shot pulling. It sounded like when the water in the boiler is low and it pulls water in from the reservoir. The sound wouldn't stop even after the shot was finished pulling. The only way to get the noise to stop was to turn the power off. I took the screws off and removed the lid to get a better look at what was going on. I filmed the 3 clips by having my girlfriend turn the power on and then turn it off while I filmed. Keep in mind that the noise is NOT from the machine pulling water through the group head. I can clearly see water and air shooting out from the boiler where the boilersteam tap tube (i think that is the part from looking at the exploded parts diagram on nuova's website) goes into the boiler. I see water dripping down from the underside of the p-stat but I think that is from the water shooting up from the boiler and hitting it. I don't necessarily think anything is leaking from the p-stat, nor do i even know if that is a possibility. you can probably tell i don't know much about the inner workings of my machine. haha. Does anyone know what has gone wrong here? If so, do you think it is something i can fix on my own or should I be contacting an appliance repair person for doing the job? I do like to take things apart and mess with them, but we just moved and are living in a hotel and i don't even have my tool set with me. FML. anyways, thanks for any advice or help guys and girls.

regards,
Scott

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drgary
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Joined: 14 years ago

#2: Post by drgary »

If it only happens when you turn on the pump, something is happening in the pump, the connections that feed it or the pressurized brew path it drives. Is the leak hidden by the boiler insulation? You may need to sacrifice the insulation to see the source.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

ricky analog (original poster)
Posts: 31
Joined: 9 years ago

#3: Post by ricky analog (original poster) »

This is not something that happens when I run water like I am pulling a shot, if that is what you mean by "If it only happens when you turn on the pump." This is happening as soon as the power is turned on and doesn't stop until I turn the power off. My guess is that it is caused by the system not being airtight and having pressure escape through the problem area.

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drgary
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#4: Post by drgary »

I peeled the insulation off an old Oscar and found a number of leaks, evidenced by oxidizing copper, scale and pinholes that looked like they could break through. You might check your boiler for similar holes. I didn't try to run it before starting the teardown, but at this point I'm pricing the cost of a replacement boiler instead of risking something that may be degrading from the inside.

Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

estib
Posts: 34
Joined: 10 years ago

#5: Post by estib »

Looks like there's something wrong with the water level probe. If you notice as soon as you turn on the machine the heater indicator/lamp turns off, it does this when it detects low water level inside the boiler. So it starts pumping water into the boiler and since there's a problem with the water level probe, it doesn't stop filling and water comes out of the safety valve.