Hi Folks! I'm rebuilding a used Nuova Simonelli Premiere Maxi and I've run into a few snags. I'll start from the beginning.

In October I acquired the machine. It had been unplugged, disconnected and stored a while, with a little water in the tank and had some pretty severe scale build up, along with one of the group heads being neglected and pretty unusable.

I did almost a complete tear-down, acid bath descaling and rebuild (I didn't really mess with the pumps and the electronics, mostly just the copper and brass), replacing some parts with an order from espressoparts.com. As far as I could see, it all looked pretty good and I was proud of myself.

At this this point the assembled machine sat on the shop counter, awaiting new electrical and plumbing to be completed in our new coffeeshop.

Last weekend, we finally got machine plugged in and the water hooked up, running through a single canister GE SmartWater filtration system.
We flipped the switch on and within a few minutes the tank filled up and squirted water out if the steam wands. We shut it off and shut the water off and left it to drain, which took a day or so. I'm thinking that maybe the water level sensor in the tank is not working for some reason. It seemed fin on the rebuild but I've read a few things here that suggest that water can be too soft to trigger the sensor? It all still has a slight acid smell still too. Is the machine designed to self-flush?

Another problem is the electronics on one of the group heads. When the pour button is pressed, there's a loud rattling buzz that quickly makes us turn the switch back off. I'm guessing this might be a bad electrovalve cube, since the buzz sounds more like too much power, rather than a jammed pump or something mechanical.

Sorry if everything's a little vague. Any thoughts on where to start from here would be much appreciated.

Thanks for reading. - Carl

I would start here: http://www.nuovadistribution.com/premiermaxi.html

Troubleshooting the water level probe is simple. Remove the spade connector from the probe and turn on the machine. Pump should run to fill the boiler. Touch the connector to the boiler metal .. pump should stop. If it doesn't stop, your problem is either in the wiring to control unit, or the control unit itself. If it does stop, your problem is the probe or the conductivity of the water (and a single salt crystal will fix that).

The rattle in the solenoid valve can be caused by either a faulty coil or crap inside the valve itself. Swap the coil with the good one from the other group, if the problem persists then you need to clean out the valve. Replacement coils are cheap.

Alan