Episode 71: Stop Blaming the Compressor: Fix the Whole Air System

Jason Reed

Welcome to the show! Lisa, I wanna start with the most common phone call in this business: “We’ve got water in the line, pressure’s dropping, power bill’s up -- the compressor’s bad.” And sometimes, sure, the compressor IS the problem. But only about 40% of compressed air problems start there. Which means roughly 60% start somewhere else in the system, and that’s the part people skip right over.

Lisa Saunders

That 60% is the part that sticks with me. Because if more than half the trouble is NOT the compressor, then a lot of plants are chasing the loudest, most expensive box in the room just because it’s obvious. It’s like blaming the engine when the real problem is a flat tire, a clogged fuel filter, or, I don’t know, somebody pinched the line shut downstream.

Jason Reed

Exactly. The compressor gets blamed first because it’s big, it’s noisy, and everybody sees it. But compressed air is a system. Compressor, dryer, storage tank, filters, drains, controls, piping, end use -- all of it. If you’ve got low pressure at the far end of the plant, that could be an undersized machine... or it could be leaks. And leaks are a monster. The average leak rate people cite in the U.S. is around 30% of system capacity. Thirty. Percent. That means you may not have a compressor problem at all -- you may have a “we’re paying to make air we never use” problem.

Lisa Saunders

Wait -- 30%? So if a plant thinks it’s short on air, there’s a decent chance they’re not short on production capacity, they’re short on discipline. They’re just bleeding it off through couplings, hoses, fittings, open blow-offs... all the usual suspects.

Jason Reed

That’s a blunt way to put it, but yeah. And then they crank pressure up to compensate, which drives energy costs even higher. Same with dirty filters. A plugged filter adds restriction. Restriction adds pressure drop. Then somebody says, “This compressor won’t build pressure.” Well... maybe it can. Maybe the air just can’t get through the mess you haven’t changed.

Lisa Saunders

And moisture’s a good example too, right? Because people see water carryover -- maybe they’re getting blisters or fisheyes in paint, maybe valves are getting wet, maybe tools are spitting water -- and they go straight to “bad compressor.” But the compressor is just compressing the moisture that was already in the ambient air. The real question is: where’s the dryer, what condition is it in, and are the drains actually draining?

Jason Reed

Bingo. If drains are clogged, if separators aren’t working, if the dryer’s undersized or not doing its job, that water’s going downstream. And here’s another one people miss: piping. You can’t run most of the plant on a decent main and then neck it down from a two-inch line to a half-inch bottleneck and act surprised when pressure falls off. That pressure drop isn’t magic. It’s designed in -- usually by accident.

Lisa Saunders

“Designed in by accident” is painfully accurate. And poor storage belongs in this conversation too. Because short cycling gets blamed on the compressor a lot -- “this thing keeps starting and stopping, it must be faulty” -- when the issue can be that the system doesn’t have enough receiver capacity to buffer demand swings.

Jason Reed

Right. The machine may be responding to a bad setup. If demand jumps fast and you don’t have enough storage, the compressor’s forced to chase every little blip. That’s hard on equipment, inefficient, and it leads people to replace stuff that wasn’t the root cause in the first place. So the simple version is: symptoms show up at the compressor, but the cause may be leaks, filters, drains, piping, storage -- somewhere else entirely.

Lisa Saunders

So if blaming the compressor is the trap, system thinking is the fix. But let’s make that concrete. When people say “take a systems approach,” what actually changes on the plant floor? Because that phrase can sound a little... abstract.

Jason Reed

Fair. Here’s the non-fancy version: you stop looking at parts one by one and start asking whether they work together. The dryer has to match the air quality you need. The filters have to be sized for flow and pressure. The receiver has to be large enough to stabilize pressure and flow. The piping has to move air without building in a bunch of pressure drop. And the controls have to coordinate the compressors so they’re not fighting each other.

Lisa Saunders

The receiver number is one I think people remember because it’s concrete. CAGI guidance says you may need up to 10 gallons of storage per CFM of flow from the largest compressor. Up to 10 gallons per CFM. That’s not “throw a tank in there and call it good.” That’s actual sizing.

Jason Reed

Yeah, and storage matters even more when people start talking about VSDs -- variable-speed drives -- like they’re a magic fix. VSDs can absolutely save energy when demand swings around. At 50% load, a VSD unit can use roughly 50% of the energy of a fixed-speed machine. That sounds great. But if you drop a VSD into a system with lousy storage, bad controls, and erratic demand, it may hunt, cycle excessively, and spend its life reacting instead of running smoothly.

Lisa Saunders

So the sales pitch is “buy the smart compressor,” but the smarter question is, “Is the system around it ready for one?” Because if storage is weak and sequencing is sloppy, the VSD doesn’t look smart -- it looks irritated.

Jason Reed

That’s exactly it. A VSD should be applied to actual demand variability, not wishful thinking. Same story with multi-compressor systems. If you’ve got base-load, trim, and backup units, they need sequencing. One lead machine, the others following instructions, and ideally the whole setup operating inside a pretty tight pressure band. Properly configured master controls can keep that band around plus or minus 2 PSIG. And that matters because every extra pound of pressure you run “just to be safe” usually costs you money.

Lisa Saunders

That plus-or-minus 2 PSIG number is the thing I’d circle. Because that’s the difference between a stable system and one that feels jumpy all day. And with controls now, you can network multiple compressors -- even from different manufacturers -- which is a big deal in real plants where nobody has a perfectly matched fleet.

Jason Reed

Yep. And once you think that way, maintenance changes too. You stop treating symptoms. Instead of saying, “Drain failed again, replace it again,” you ask why moisture loading is high. Instead of “pressure’s low, turn it up,” you ask where the drop is happening. Instead of “compressor short cycles, must be bad,” you check storage and controls. That root-cause mindset cuts repeat failures, emergency calls, downtime -- all the expensive stuff that comes from being reactive.

Lisa Saunders

And it changes the culture a little, too. Preventive maintenance is one thing -- change filters on schedule, inspect what needs inspecting. Useful, necessary. But when you start paying attention to pressure trends, temperature, energy use, cycling patterns, you move closer to predictive thinking. You’re not just servicing equipment because the calendar says so. You’re reading the behavior of the system.

Jason Reed

Which is really the whole point. Compressed air gets expensive when you treat it like a collection of unrelated parts. It gets a lot more manageable when you treat it like one machine made out of many pieces. And honestly... once you see the system that way, it’s hard to unsee how many “compressor problems” were never compressor problems at all.

Lisa Saunders

Yeah. And that’s the uncomfortable question to leave hanging: if your first instinct is always to blame the compressor, what else in the plant are you probably misdiagnosing the exact same way?