Question:
The espresso techie types might be interested in this. I bought a new pump for my Isomac Millenium. It isn't a pump normally used on espresso machines, but for industrial/commercial applications such as floor care machines and drinking water delivery systems. It will allow me to plumb-in the machine. And, it will fit inside the IM where the smallest Procon doesn't. I'll report back after it is installed, perhaps over the holiday.Sounds interesting.

How many $?

Answer: Dunno. The prevaling authority would probably be NSF, not FDA since not many of us can swallow a pump wholeOther pumps in the line are used for potable water supplies, so I'm comfortable with this one

That's the kind of pump used in espresso carts (or my kitchen), to pump out of a tank, and feed to the rotary pump. In the cart setup however, there's an accumulator attached to the pump that maintains output pressure constant until empty, then the pump activates to fill the accumulator again. The reason is so that the pump doesn't come on/off as often as you'll need water, but only as often as the accumulator needs to be refilled. So, longevity of the pump *might* be an issue, not sure if it's meant to be used without an accumulator when used for an espresso machine. Then again, you won't be pulling shots continuously, so it's probably fine ... About the check valve, it's built in, no need to worry about that.