Is it a hydraulic pump with the tank as the reservoir?

Yep, specifically a "shallow well" (If you want more info, email me and I'll take you through suction line size, foot valves, strainers, priming, etc.

Have fun,

Ev

Thanks exmar! A reply on the other board (below) and yours should help O/P.

" It almost looks like a shallow well pump more than it looks like an air compressor.

On edit it is a well pump I had to think about it for a few minutes but its a shallow well pump sitting on a pressure tank. Judging by the plumbing on it someone may have set it up to run an irrigation system off of their well. The beeping that the op heard I'm guessing is the sound of the pump attempting to prime itself.
Had I not just installed a new well pump for my aunt I wouldn't have recognized what it was "