Drift in an Atlas Copco ZR160 is a slow, silent gap between what the compressor should deliver and what it actually delivers. If you don't measure it, you won't see it until the production line loses pressure or your electricity bill jumps. I manage purchasing for a mid-sized manufacturing plant, and after five years of dealing with compressors, I've learned this: check drift monthly, not when a service alarm tells you to. The machine can look perfectly fine on the outside and be slowly turning into an expensive problem inside.
What Is Drift, Exactly?
Drift is the difference between the compressor's rated output and its current performance. In a ZR160, that usually shows up in one of three ways: lower free air delivery, higher specific energy consumption, or oil-free air quality that quietly starts to loosen. None of these are instant failures. They are slow shifts that, left alone, become 'sudden' failures.
It's tempting to think a modern controller will tell you everything. The ZR160 has a screen, remote monitoring options, and a lot of data. But the controller measures what the machine reports, not necessarily what the system is doing. When we compared the ZR160's reported pressure with a calibrated meter on the same line, the gap was about 0.6 bar under sustained load. That's not a reason to distrust Atlas Copco. It's a reason to verify.
How I Learned This the Hard Way
At the first congress I attended on compressed air systems, a service engineer said something that didn't fully land until later:
Most machines don't fail. They drift.
I remember rolling my eyes a little. It sounded like a motivational poster for maintenance. Then our plant's energy bill arrived.
Our ZR160 had been running for about 14 months. The air system seemed fine. No alarms, no complaints from production, no oil in the condensate. But energy per unit of output was up 17% compared with the previous year. I called the service team, and the diagnosis was exactly what that engineer meant: intake filter loading, a slowly leaking condensate valve, and pressure settings that had been changed during a hot summer and never reset. None of these were dramatic. Together, they made the compressor work harder for the same result.
The most frustrating part: if I had checked the drift points earlier, the whole problem would have been a three-hour service visit. Instead, we spent two weeks chasing intermittent line pressure issues, lost production time, and paid for a follow-up energy audit. You'd think a screen full of green numbers would be enough, but it isn't.
Where the ZR160 Fits
I'm an administrator, not an engineer, so I'll stick to what I saw in the purchase and operation of our ZR160. It's an oil-free rotary screw compressor, and the reason we chose it was simple: our packaging line needed clean, consistent air, and the oil-free design removed a whole category of contamination risk. The Atlas Copco data sheet lists Class 0 oil-free air per ISO 8573-1, which mattered more to our quality manager than to me. After seeing what oil carryover does to production, I now understand why he pushed for it.
The ZR160 is also part of a bigger decision. We run pneumatic assembly tools off the same system, including Atlas Copco screwdrivers—avvitatori Atlas Copco in the Italian product literature—and the maintenance team appreciated having one service partner for both the air room and the tooling. For me, that simplified the vendor list and made the annual service contract easier to justify.
But here's the anti-intuitive part: buying a better compressor doesn't reduce the need to check it. It raises the stakes. You spend more on the machine, the air quality certification, and the installation. If you let drift go unnoticed, the return on that investment starts leaking out in ways that don't show up on the compressor's own display.
What I Check Now
I didn't create this checklist from a textbook. I built it after the expensive lesson above, with input from our service technician. It takes about 20 minutes a month, and the first time we ran it, we found a pressure switch set 0.3 bar below specification—enough to change the way the ZR160 loaded and unloaded during the day.
- Actual delivery pressure vs. controller reading. Put a calibrated gauge on the receiver tank and compare it with the machine's display.
- Specific power trend. Track kWh per cubic meter of air produced. That's the number that caught our 17% issue.
- Intake filter differential. The filter can look fine from the outside and still be restricting airflow.
- Condensate drains. Timers fail open. Listen for one that cycles too often or stays silent.
- Air quality records. Oil-free machines are not maintenance-free. Class 0 depends on seals, filters, and a correctly functioning control system.
This is not a replacement for the manufacturer's preventive maintenance schedule. It's an extra layer that works for a plant like ours, where the maintenance department is small and the compressor isn't the only thing they look after.
When I'm Wrong
I'm not saying every ZR160 owner needs this exact list. If your compressor runs in a controlled environment, gets serviced by the same engineer every time, and already has remote performance logging with alerts, you may catch drift earlier. The boundary condition matters: the more stable your load profile, the less often you need to look. But even in the best case, I'd still recommend a 20-minute monthly check. It's the cheapest insurance I've found in industrial purchasing.
One more thing. This isn't like ordering Halloween costumes for the office. With costumes, the mistake is visible and easy to fix. A compressor can drift for months before anyone realizes there's a problem, and by then the fix isn't a return—it's a correction that costs more than the check would have. Take it from someone who found out the expensive way.