Hydraulic power units (HPUs) are everywhere — many jackhammers, most auto lifts that mechanics walk under, many fishing boats’ net-haulers, almost every big yellow machine you see at a construction site all use hydraulic power units. Obviously they come in quite a variety — how do you know you’re getting the right one for your needs?

At it’s simplest, when you need a single HPU to power a single tool, the answer is usually written right on (or in the instruction booklet of) the tool in question. You need an HPU that provides at least enough actual hydraulic fluid to power the tool (for handheld tools, a half-gallon is usually all you need, but for industrial applications, a 250 gallon tank isn’t unheard of.) It also needs to supply adequate pressure to get the job done — your typical hydraulic jackhammer, for example, won’t function at less than 1300 psi.

But the simplest is hardly adequate to most industrial applications. If you’re, say, a machine shop, and you need a single hydraulic power unit that can provide hydraulic power to a dozen different metal grinders, pipe benders, sheet stampers, and so forth, you’ve got a lot more to worry about than just matching one machine’s numbers to another’s.

Fortunately, it’s still not all that difficult — many providers have or can custom-build a hydraulic manifold that can ensure that, as long as your HPU is capable of producing adequate flow and pressure to handle all of the jobs you want to simultaneously accomplish, each tool gets the right amount of fluid at the right pressure. Such a manifold will have pressure-reducing valves and both automatic and controllable switches that will ensure no machine gets too much pressure or fluid for it’s own operation, but all machines get enough of each.

Those aren’t the only details — there are other considerations that range from the possible need to move your HPU to different areas at different times, or matching the power consumption of your HPU to the type of power provided by your shop’s outlets — but those should mostly be intuitive for your typical shop manager.