Epiosde 27: Full Load and Duty Cycle

Jason Reed

Welcome back to The Big Dog Podcast, everyone! I’m Jason Reed, and as always, I’m here with Lisa Saunders. Today, we’re getting into something that, honestly, I think gets overlooked way too often—full load, duty cycle, and demand profile. These are the things that actually run your shop, whether you realize it or not.

Lisa Saunders

Yeah, and I’ll admit, when I first started learning about compressed air, I thought, “Okay, a compressor’s a compressor, right?” But there’s a lot more to it. So, Jason, let’s break down these terms for folks who might be new to this. What’s full load, in plain English?

Jason Reed

Sure. Full load is basically the max output your compressor can give. When you’re running at full load, you’re getting all the compressed air that machine was designed to produce. But—and this is where people get tripped up—if you crank up the pressure, you actually lose some flow. So, more pressure doesn’t always mean more air. It’s kind of a balancing act.

Lisa Saunders

Right, and then there’s duty cycle. That’s the percentage of time your compressor can safely run without, you know, cooking itself. Some compressors are built for 100% duty cycle, so they can run all day. Others, like reciprocating compressors, really shouldn’t be running more than half the time or so, or you’re asking for trouble.

Jason Reed

Exactly. I mean, I’ve seen shops run a little piston compressor flat out, thinking it’s saving them money, but all they’re doing is wearing it out. Recips are great for intermittent use, but if you need air all day, you want a rotary screw or centrifugal. Those are built for 100% duty cycle—run ‘em hard, they’re happy.

Lisa Saunders

And then there’s demand profile, which is honestly where a lot of people mess up. It’s not just about adding up the CFM of every tool you own. You have to look at what’s running at the same time, and whether it’s continuous or just in short bursts. Like, nail guns versus pneumatic controls—totally different story.

Jason Reed

Yeah, and I gotta share this—so, I was at a plant a while back, and they’d sized their system thinking every single tool would be running at once, all day. They ended up with this monster compressor that barely ever hit full load. It was cycling on and off, burning through energy, and just racking up maintenance headaches. If they’d actually looked at their demand profile, they could’ve saved a ton of money and hassle.

Lisa Saunders

That’s exactly what happened at Unverferth Manufacturing in Iowa, right? They brought in an audit, looked at their base load, duty cycle, and demand profile, and realized they could downsize and still get better reliability. It’s not just about buying the biggest machine you can afford.

Jason Reed

Nope, it’s about matching the system to what you actually need. Otherwise, you’re just paying for problems you don’t want.

Lisa Saunders

So, let’s talk compressor types for a second. You’ve got reciprocating, rotary screw, and centrifugal. And the big difference, at least for me, is how they handle duty cycle and what they’re actually good for.

Jason Reed

Yeah, recips are your classic piston compressors. They’re great for stuff that’s on and off—like, say, a tire shop or a place with a bunch of nail guns. But if you try to run them all day, you’re gonna overheat them. They just aren’t built for that.

Lisa Saunders

And then rotary screw and centrifugal—those are the workhorses. They’ve got internal cooling, so they can run 100% duty cycle. If you’ve got sanding equipment or spray painting that’s running all shift, that’s what you want. But, you know, I’ve seen people put a giant rotary screw in a shop that only uses air in short bursts. It just sits there, cycling on and off, and it’s not happy.

Jason Reed

That’s the thing. You gotta match the compressor to the job. I mean, I’ve seen maintenance teams get stuck with rapid cycling because someone oversized the compressor. The machine’s constantly starting and stopping, and that’s just brutal on the equipment. It’s like, you wouldn’t buy a semi truck to drive your kid to school, right?

Lisa Saunders

Yeah, and I remember this one case—maintenance team was pulling their hair out because their compressor was cycling so fast. Turns out, it was way too big for what they actually needed. They could’ve gone with a smaller unit or even a couple of smaller ones, and it would’ve been way more reliable.

Jason Reed

Exactly. And sometimes, it’s not just about the compressor itself, but how you set up the whole system. Like, do you need storage tanks? Are you running everything off one unit, or do you have a backup? All that stuff matters.

Lisa Saunders

And don’t forget, intermittent tools and continuous-use systems need totally different approaches. If you’re running a bunch of impact wrenches for a few seconds at a time, that’s not the same as running pneumatic controls 24/7. You gotta look at the real-world usage, not just the spec sheet.

Jason Reed

Alright, so let’s get into sizing and system design, because this is where people really get burned. Oversizing is just as bad as undersizing, maybe worse. I mean, with rotary screw compressors, if you oversize, you’re wasting electricity and you’re gonna get rapid cycling. That’s a maintenance nightmare.

Lisa Saunders

Yeah, and undersizing is no picnic either. You end up with pressure drops, tools that don’t work right, and everyone’s mad at maintenance. But oversizing is sneaky, because it feels like you’re playing it safe, but you’re actually just setting yourself up for higher costs and more breakdowns.

Jason Reed

That’s why multiple-compressor systems are so smart. You’ve got your base load compressor that handles the minimum demand, a trim compressor for the peaks, and a backup in case something goes down. That way, you’re not running a huge machine at 20% all day, and you’ve always got coverage if something fails.

Lisa Saunders

And it’s not just theory—Unverferth Manufacturing did this. They brought in a professional air audit, looked at their actual demand profile, and reconfigured their system. They ended up saving money and getting way more reliability. Sometimes, just having someone come in and look at your setup with fresh eyes makes all the difference.

Jason Reed

Yeah, and honestly, almost any company can benefit from an air audit. It’s not just for the big guys. Even a small shop can find savings or avoid a big mistake. The key is, don’t guess—get the data, look at how you’re actually using air, and size your system to fit. That’s how you avoid downtime and keep things running smooth.

Lisa Saunders

Totally. And if you’re not sure where to start, there are experts out there—like the folks at Kaishan’s distributor network—who can help you figure it out. It’s not about selling you the biggest machine, it’s about getting you the right system for your needs.

Jason Reed

Alright, I think that’s a good place to wrap it up for today. If you take anything away from this episode, it’s that understanding your load, duty cycle, and demand profile isn’t just technical jargon—it’s the difference between a reliable, efficient shop and a whole lot of headaches.

Lisa Saunders

Couldn’t have said it better. Thanks for hanging out with us on The Big Dog Podcast. We’ll be back next time with more real talk and practical tips. Jason, always a pleasure.

Jason Reed

You too, Lisa. See you next time, folks. Take care.