My Nuova Simonelli Oscar Has recently begun venting steam when it is on. It seams to build up pressure and then suddenly vent it. It will do this about every 2-3 minutes once it has warmed up. It never did this before.

Does anyone have any insights?

Thanks,
Alfred

Where is the steam coming from? If its coming from the pressure relief valve then it's faulty and needs to be replaced.

If I remember right, the Oscar does not have a boiler pressure gauge. It sounds like the pressurestat is sticking closed which will then cause the heating element to keep running until the pressure builds up high enough to vent through the safety valve. If that's the case, a pressurestat replacement is probably needed.

Here is a video of what it is doing:

https://www.youtube.com/watch?v=C7lGOIu ... e=youtu.be

alfredw wrote:Here is a video of what it is doing:

https://www.youtube.com/watch?v=C7lGOIu ... e=youtu.be

It is a simple case of the pressure stat not doing its intended job (stopping the heating element from building pressure past a certain point) consequently forcing the safety valve to release the excessive pressure that's where you hear this hissing sound . The P-Stat usually fails on used machine so it is not such a big deal and is rather inexpensive to buy and replace. You can certainly try to adjust the current P-Stat by either turning the main knob anti-clockwise (risky) or trying to clean the connecting wires in the hope it will solve the issue (unlikely).

So go ahead and buy a new P-Stat, I believe you have two types available to you, CEME OR MATER. I think CEME is installed on the Oscar but you can still fit a MATER in by twisting its wires a bit more.

Good luck.