Why Your Air Compressor Runs Constantly (And What It’s Trying to Tell You)

If your air compressor seems like it never shuts off, that’s not just annoying background noise — it’s your system trying to tell you something is wrong.

In many manufacturing plants, automotive shops, fabrication facilities, and production floors around Nashville, LaVergne, Murfreesboro, Smyrna, and across Rutherford, Davidson, and Hamilton Counties, we see compressors running nonstop day after day. Operators often assume that’s just how the system works. In reality, a compressor that runs constantly is usually a sign of inefficiency, hidden damage, or an air system that’s being pushed beyond what it was designed to handle.

Let’s break down what’s really happening — and why ignoring it can quietly cost you thousands.

A Healthy Compressor Should Cycle

Most industrial air compressors are designed to cycle. Even rotary screw compressors that run longer duty cycles should still unload, modulate, or stage down based on demand.

When a compressor never gets a break, it usually means one of two things:

The system is losing air faster than it can produce it, or

The system can’t keep up with actual demand

Either way, constant run time is not normal — and it almost always leads to higher energy bills, premature wear, and unexpected breakdowns.

Air Leaks: The Most Common Culprit

The number one reason a compressor runs continuously is air leaks.

Leaks don’t have to be dramatic to cause major problems. A few small leaks scattered throughout a facility can add up fast. In older buildings around downtown Nashville, Antioch, Madison, or legacy manufacturing plants in Chattanooga, leaks often hide in plain sight.

Common leak locations include:

Quick-connect fittings

Hose reels

Threaded joints

FRLs (filters, regulators, lubricators)

Drop legs and low points

Aging black iron piping

What makes leaks so dangerous is that they get worse over time. Temperature swings, vibration, and moisture slowly open up gaps that weren’t there before. As leaks increase, the compressor works harder to maintain pressure — until it’s running nonstop just to keep up.

Pressure Drop Forces the Compressor to Overwork

Another major reason compressors run constantly is pressure drop.

Pressure drop happens when air can’t move efficiently through the system. The compressor may be producing enough air, but restrictions prevent that air from reaching the point of use at the pressure you need.

Common causes include:

Undersized or outdated piping

Long pipe runs with too many elbows

Clogged filters

Moisture buildup

Poorly designed system layouts

When pressure drops at the end of the line, operators often compensate by turning the compressor pressure up. That might solve the immediate problem, but it forces the compressor to run longer, hotter, and less efficiently — often without ever reaching a true unload condition.

Undersized Compressors and Growing Demand

Facilities change over time, but air systems are often left behind.

A compressor that was perfectly sized five or ten years ago may now be undersized due to:

Added equipment

More shifts per day

Increased automation

Higher air demand tools

Expanded production areas

In fast-growing areas like Murfreesboro, Spring Hill, and Mt. Juliet, we regularly see plants outgrow their original air systems. The compressor runs constantly not because it’s failing — but because it’s doing everything it can.

Running an undersized compressor nonstop dramatically shortens its lifespan and increases the risk of sudden failure.

Insufficient Air Storage Makes Things Worse

Air receiver tanks don’t get much attention, but they play a critical role in compressor cycling.

Without enough storage:

The compressor short-cycles or never unloads

Pressure fluctuates constantly

The dryer gets overloaded

Energy use spikes

Poorly placed tanks can be just as bad as undersized ones. A system without proper wet and dry storage forces the compressor to chase every small demand spike — keeping it running far longer than necessary.

In many cases, adding or relocating storage is one of the fastest and most affordable ways to reduce constant run time.

Control Settings and Sensors Matter More Than You Think

Sometimes the issue isn’t mechanical at all — it’s how the compressor is being controlled.

Problems we often find include:

Faulty pressure switches

Poorly calibrated transducers

Incorrect load/unload setpoints

Controllers fighting each other in multi-compressor systems

When controls aren’t communicating properly, compressors can stay loaded even when demand drops. This is especially common in older systems that have been modified or expanded over time without updating controls.

Moisture Problems Increase Run Time

Moisture doesn’t just damage tools and piping — it also increases compressor workload.

Water in the system causes:

Clogged filters

Restricted airflow

Corrosion inside piping

Increased pressure drop

In humid Middle Tennessee summers, moisture issues can escalate quickly. A compressor that ran fine in winter may struggle in July and August, running continuously just to maintain pressure.

Dryer performance, drain operation, and proper moisture management all play a role in keeping run time under control.

Why Constant Run Time Gets Expensive Fast

A compressor that never shuts off costs more than just electricity.

Long-term consequences include:

Higher energy bills every month

Increased wear on bearings, motors, and air ends

Overheated oil and reduced lubrication

Shortened service intervals

Greater risk of emergency shutdowns

Many emergency service calls we respond to in Nashville, Knoxville, and Chattanooga start with the same sentence:
“It’s been running nonstop for a while, but we didn’t think much of it.”

By the time a compressor fails, the warning signs have usually been there for months.

When Constant Run Time Is a Warning — Not a Feature

Some operators assume nonstop operation is normal for rotary screw compressors. While it’s true they’re designed for longer duty cycles, they still need periods of unloading or modulation to stay healthy.

If your compressor:

Rarely unloads

Runs hot

Sounds different than it used to

Trips alarms more often

Consumes more power than before

…it’s time to investigate.

The Smart Move: Diagnose the Cause, Not the Symptom

Turning the pressure up, adding another hose, or “living with it” doesn’t fix the problem — it hides it.

The right approach is to:

Identify leaks

Measure pressure drop

Evaluate storage and piping

Review control settings

Compare demand to compressor capacity

Once you know why the compressor is running constantly, the fix is usually straightforward — and far less expensive than a major breakdown.

Local Help Makes a Difference

At Industrial Air Services, we help facilities across Nashville, LaVergne, Murfreesboro, Smyrna, Knoxville, and Chattanooga track down the real reasons their compressors never shut off. From leak detection and storage upgrades to system evaluations and preventive maintenance, we focus on practical fixes that reduce energy use and extend equipment life.

If your compressor seems like it never gets a break, it’s worth taking a closer look.

📞 (615) 641-3100
📍 138 Bain Drive • LaVergne, TN 37086