Episode 33: Stop Compressor Cycling

Jason Reed

Alright, welcome back to The Big Dog Podcast. I’m Jason Reed, and as always, I’ve got Lisa Saunders with me. Today, we’re talking about something that’s, honestly, killing more rotary screw compressors than most folks realize—short cycling. Lisa, you ever walk into a compressor room and just hear that constant gear-shifting sound? It’s like the machine’s stuck in traffic, right?

Lisa Saunders

Oh, absolutely. It’s that “vroom, pause, vroom, pause” rhythm—like a car that can’t decide if it wants to go or stop. And you know, it’s funny, because a lot of people just tune it out. They think, “Well, that’s just how it runs.” But it’s not supposed to sound like a drag race in there.

Jason Reed

Exactly. And for anyone new to this, let’s break it down real quick. Rotary screw compressors cycle between loaded and unloaded states. When it’s loaded, the inlet valve opens, air comes in, gets compressed. Unloaded, that valve shuts, and the machine’s basically idling. Every time it switches, that’s a cycle. You can hear it, and you can see it on the controller if you’re paying attention.

Lisa Saunders

But here’s the thing—most users don’t really think about how often that’s happening. I mean, why do you think that is, Jason? Is it just “business as usual” syndrome?

Jason Reed

Yeah, I think so. People get used to the noise, or they assume it’s normal. But what they don’t see is the violence going on inside that machine every time it loads and unloads. It’s like slamming on the brakes and then flooring it, over and over. And, honestly, the danger is that you’re just burning through the lifespan of your compressor without even realizing it.

Lisa Saunders

Right, and it’s not just about the noise or the annoyance. It’s about what’s happening to your equipment. If you’re ignoring cycling frequency, you’re basically setting yourself up for more maintenance, more downtime, and a much shorter compressor life. And, as we’ve talked about in past episodes, that’s the kind of “business as usual” that gets expensive fast.

Jason Reed

Yeah, and if you’re hearing that gear-shifting sound every minute or so, that’s a red flag. We’ll get into what that actually costs you in a second, but first, just know—if you’re not paying attention to cycling, you’re missing one of the biggest silent killers in your system.

Lisa Saunders

So let’s talk about what’s really happening inside your compressor when it’s short cycling. Every time it loads and unloads rapidly, you’re putting extra wear on the motor, the valves, the bearings—basically all the moving parts. And it’s not just wear and tear. You get overheating, wasted energy, and even carry-over of moisture and oil. It’s a mess.

Jason Reed

Yeah, and I’ve seen compressors burn out in six months because of this. Six months! That’s wild. It’s basic physics—if you’re constantly starting and stopping, you’re just asking for trouble. And the main culprits? Not enough storage, pressure bands set too tight, or the compressor’s just oversized for the job. Sometimes it’s all three.

Lisa Saunders

I had a client once—big facility, lots of demand swings. They put in this massive compressor, thinking bigger was better. But what happened? The thing was cycling on and off non-stop. Maintenance was out there every week, swapping out parts, dealing with overheating alarms. Their budget for repairs just kept climbing, and the downtime was killing their production schedule.

Jason Reed

That’s the thing—how often is too often? If your compressor’s cycling every 40 or 60 seconds, that’s way too much. I mean, we’ve walked into rooms where it’s cycling 60 times an hour. That’s like driving with your foot on the gas and then slamming the brakes, over and over. It’s not sustainable.

Lisa Saunders

And the real-world impact? It’s not just the cost of parts. It’s the lost production, the emergency service calls, the energy bills. If you’re running 20 cycles an hour, you should be trying to get it down to 15, or even lower. Honestly, the goal is as close to zero as you can get. Every cycle you cut out is money saved and life added to your compressor.

Jason Reed

Yeah, and as we said in our episode on maintenance and cost-cutting, these little things add up. If you’re not tracking cycling, you’re probably spending more than you need to—on both repairs and energy. So, if you’re seeing 20 or more cycles per hour, it’s time to take a hard look at your setup.

Jason Reed

Alright, so what do you actually do about it? There are a few solid fixes. First, adding more storage—bigger air receivers—can help balance out those demand spikes. That way, your compressor isn’t reacting to every little blip in usage. Then you’ve got variable-speed drives, or VSDs. They let the motor ramp up and down smoothly, instead of just on-off, on-off. That alone can cut cycling way down.

Lisa Saunders

And don’t forget modulation. It’s a little different from VSDs—it adjusts the inlet valve to control how much air is coming in, so you don’t get that violent stop-start action. It’s a lot gentler on the machine, and it’s actually standard on some of the Kaishan models, like the KRSD and KRSP lines. I know some folks worry about efficiency with modulation, but the data just doesn’t back that up. In most cases, it’s a huge win for reliability.

Jason Reed

Yeah, I saw this firsthand at a local manufacturer. They were dealing with constant cycling—like, every minute. We swapped in a VSD, and it cut their cycling in half, almost overnight. Maintenance calls dropped, energy use went down, and the machine just ran smoother. Sometimes it really is that simple.

Lisa Saunders

But here’s the thing—if you’re not sure what’s causing your cycling, or you’re seeing 20-plus cycles an hour, that’s when you call in the pros. A good compressed air consultant can look at your storage, your pressure settings, your compressor size, and help you figure out what’s really going on. And, honestly, that first conversation can save you a ton of headaches down the road.

Jason Reed

Yeah, don’t wait until you’re burning through motors or dealing with constant downtime. If you’re hearing that gear-shifting sound more than a handful of times an hour, it’s time to act. Start with storage, look at VSDs or modulation, and don’t be afraid to get expert help. That’s what keeps your system running—and your budget in check.

Lisa Saunders

Alright, that’s gonna do it for this episode of The Big Dog Podcast. If you’re dealing with cycling headaches, or just want to make sure your system’s set up right, reach out to your local expert or check out the resources on the Kaishan website. Jason, always a pleasure.

Jason Reed

Same here, Lisa. Thanks for tuning in, everybody. We’ll be back soon with more ways to keep your compressed air system running strong. Take care!

Lisa Saunders

See you next time on The Big Dog Podcast!