Nuova simonelli appia compact leaky steam wand

SOURCE: nuova simonelli appia 1 ....pump will not stop pumping so tank fu

Your level probe is on the right hand side plate of the boiler, normally with a red wire leading to it.
I would take the probe out (spanner reqd, obv. with no pressure in the boiler) and clean it with wire wool.Scale often causes the probes to malfunction.
Then make sure when you refit the probe, the part of the probe in the boiler faces down.

SOURCE: Empty light on espresso machine won't turn off and tank is full

I have the same machine. I just went on the coffee geeks website and it is easily solved. Just add a few grains of salt to the reservoir - the sensor cant detect water that is purified - strange but true as four grains and it fired up just like that.

SOURCE: My Nuova Simonelli Oscar won't get hot enough to

check element,maybe heated throught ground

SOURCE: We own a nuova simonelli oscar espresso machine

Do not remove the water reservoir from the machine...the sensor is very sensitive. Leave it in and just fill it with tap water.