Air Compressor Troubleshooting Guide

In a compressed air system, as in any plant system, problems occur during routine operation. Most of these problems are minor and can be corrected by simple adjustments, cleaning or replacing a part, or eliminating an adverse condition. Any major problem that may develop is generally related to improper cooling or lubrication, poor maintenance and operating practices, or misapplication of the system. When a problem is beyond a simple fix, our factory-trained and authorized service technicians are ready to provide expert, reliable assistance.

The air compressor troubleshooting guide below is not comprehensive, but it indicates some common problems that can develop in a compressed air system using positive displacement compressors.

Low pressure at the point of use and low pressure at the compressor discharge are two different problems that require different approaches. When pressure is adequate at the compressor but drops off at the tool or process, the issue almost always lies in the distribution system, such as undersized piping, clogged filters, or air leaks. Industry benchmarks call for the pressure drop across a well-designed distribution system to remain at or below 3% of operating pressure; anything above that signals a system design or maintenance issue. 

When pressure is low at compressor discharge, the focus shifts to the compressor's mechanical condition and control settings. Addressing the right layer of the system first saves time and avoids unnecessary repairs. 

Air leaks are among the most common and costly problems in any compressed air system, and the most frequently overlooked. A single undetected leak can cost hundreds to thousands of dollars per year in wasted energy. Our professional leak detection service uses ultrasonic technology to find and quantify leaks across your entire system, giving you a dollar figure on exactly how much air (and money) is escaping.

Moisture in compressed air lines is not simply a nuisance. It accelerates corrosion in piping, contaminates products, damages pneumatic tools and valves, and can create quality failures in sensitive manufacturing processes. The root cause is often an undersized dryer for the operating conditions, a failed condensate drain, or both. 

Many facilities originally size dryers for rated compressor flow but later increase air demand without upgrading treatment equipment; if your system has grown, it may be time to revisit your compressed air treatment sizing. 

Oil carryover is a separate but equally serious issue, particularly in food, beverage, pharmaceutical, and electronics applications where air purity standards are strict.

Heat is the leading cause of premature compressor failure, and most overheating events trace back to one of three conditions: restricted airflow, inadequate lubrication, or a compressor room environment that was never properly designed for heat rejection. Kaeser rotary screw compressors equipped with Sigma Control monitor airend discharge temperature continuously and will shut the unit down automatically before damage occurs, but that protection only works if you address the root cause rather than simply restarting the machine. 

If your Sigma Control is displaying temperature warnings or fault messages, those messages are stored in the controller's alarm history and can help our technicians diagnose the problem faster. 

Unusual noises, like knocking, rattling, or a sudden increase in vibration, are early warnings that you should never ignore. Many mechanical failures that result in costly airend replacement start as minor issues that a routine inspection could have caught. Our service technicians are specifically trained on Kaeser equipment and possess the diagnostic expertise to distinguish a loose guard from a bearing in distress.

A troubleshooting table gives you a starting point. It does not replace a thorough diagnosis. In practice, many compressed air problems share symptoms across multiple root causes, and addressing the symptoms without addressing the underlying causes leads to recurring failures. A few principles that guide effective air compressor troubleshooting in industrial settings: 

• Check the whole system, not just the compressor. Pressure problems, moisture issues, and contamination often originate downstream of the compressor in the distribution system. Before changing components, trace the problem to its source. 
• Use your controller data. Kaeser compressors running Sigma Control or Sigma Control log alarm histories, operating hours, load ratios, and service interval countdowns. That data is one of the fastest diagnostic tools available. If a fault message has appeared, document it before resetting. If needed, our service team can use that information directly. 
• Maintenance history is diagnostic information. A compressor that has exceeded its oil separator replacement interval or hasn't had a fluid change on schedule will behave differently than one that's current on planned maintenance. When troubleshooting, knowing what has and hasn't been serviced narrows the field significantly. 
• Know when to stop and call. Some faults, such as bearing failures, drive coupling issues, or refrigerant circuit problems in integrated dryers, require factory-trained expertise and specific tools. Attempting internal repairs without proper training risks further damage and creates safety hazards. Our customer service team and 24-hour emergency parts guarantee mean you won't wait days to get back online.

Some problems are a simple fix. Others need a trained eye, the right tools, and direct knowledge of your specific equipment. When the table above points you toward a repair that goes beyond basic adjustment or filter replacement, we're here to help. 

Our factory-trained and authorized service technicians work on Kaeser equipment every day. They know your compressor, its controller, and the failure modes specific to your configuration. With service centers nationwide, downtime doesn't have to result in days of lost production. 

• Request service or parts support, or find your local Kaeser representative. 
• Proactive maintenance prevents downtime. Download Our Comprehensive Compressed Air System Guide.