5 Signs An Industrial Air Compressor Needs Maintenance or Service

Man repairing

It is important for compressed air users to be familiar with their industrial air compressor maintenance needs.  Knowledge of machine performance, operating characteristics and service requirements enables the user to recognize when a specific machine requires attention. An air compressor that is operating below its design capabilities can be inefficient, costly and even dangerous.  Fortunately, most potential or impending issues show early warning signs that are easy to spot by a knowledgeable compressed air user. Air compressor operators should be on the lookout for any of the following potential warning signs, and be ready to take immediate action to limit potential failures, downtime and repair costs:

  1. High Operating Temperature

All air compressors fight a constant battle against heat.  The physical act of compressing air molecules produces huge amounts of it (known as the “heat of compression”), and effective dissipation of this heat is critical for safe and reliable compressor operation.  A sudden or unexplained rise in compressor operating temperature is a strong indicator that a problem is imminent.  Regular cleaning of a compressor’s coolers should be incorporated into any maintenance program.  Additionally, the condition of a compressor’s lubricant can greatly affect the machine’s ability to operate at a safe temperature.  Closely monitoring lubricant condition through a formal oil sampling program is a good strategy for preventing compressor failure and downtime.

  1. Increased Noise

Many industrial air compressors – especially older models – emit high operating noise.  While improving technology has enabled many compressor OEMs to reduce the overall operating noise of newer models, end users of compressed air should be familiar with the typical operating noise of their compressors during normal conditions.  Any change in operating noise should be investigated immediately.  Bearing noise should always be addressed right away, and any unexplained clicks, rattles or rumbles can forewarn a larger problem on the horizon.  If a specific noise cannot be identified or corrected, call a professional service company for troubleshooting and repair.

A vibration analysis program is highly recommended from the start on all equipment as this sets the base line vibration, then you can trend from there. This service improves the early detection of irregular vibration due to misalignment, or failing bearings etc. Also, you can check vibration on the motor same as the air end, detects early vibration issues, misalignments, soft foot, etc. worth the investment. ~ George Saez, Service Manager Sullair of Houston

  1. Motor overload or tripped breakers

Most industrial air compressors are equipped with a safety shutdown that will stop the unit automatically in the event motor amperage exceeds the acceptable range.  If a compressor shuts down due to this fault, the root cause should be investigated immediately.  Sometimes the issue can be resolved quickly with a minor adjustment by an authorized professional.  However, a motor overload or tripped breaker can often be indicative of more serious problems – such as deficiencies in a facilities’ electrical system or increased mechanical friction in the air compressor.  Regardless of the potential cause, an electrical overload should always be taken seriously and addressed immediately for the sake of safety.

  1. Low Flow or Pressure

A properly designed compressed air system should supply sufficient air flow and pressure to support the needs of the application.  If a compressed air system suddenly or inexplicably is unable to maintain adequate pressure, the results can be catastrophic to a company’s bottom line.  Poor product quality, facility downtime, and reduced safety can all eat into a company’s profits.  For these reasons, users of compressed air should be constantly aware of system performance to minimize the impact of insufficient compressed air supply.

The potential causes of reduced pressure or flow are varied – and can manifest in both the compressor room or in a facility’s air piping.  Leaking pipes, open valves and stuck drains can all cause pressure to fall.  However, sometimes the control system of the air compressor can be the culprit.  If the cause of sudden pressure loss cannot be identified immediately, call a trusted compressed air technician for assistance.

You are always going to look at your gauges or your indicators and ask ‘Are your temperatures within range? Is amperage correct? What kind of differential pressure over the separator do I have?’ Then you are going to know something is wrong and you troubleshoot it from there. ~Brad Bonnecaze, VP/COO, Sullair of Houston

  1. Increased or Excess Moisture

All compressed air systems produce liquid condensation.  This natural byproduct of the compression process is simply a fact of life for users of compressed air.  However, the presence of liquid water in a facility’s compressed air supply can be detrimental to quality, productivity and reliability.  For this reason, most end users utilize air treatment equipment such as dryers, filters and mist eliminators to remove condensation from their air systems.  If the amount of condensation in a compressed air system suddenly increases, an air treatment issue is often to blame.

“When troubleshooting this problem, start at the source and move forward.  Is the compressor’s aftercooler clean and functioning properly?  Is the compressor’s moisture separator draining?  These components are often overlooked as potential root causes, while dryers and filters get most of the attention.  However, if a dryer is being fed hot air and liquid water at its inlet, it doesn’t stand a chance.”  – Steve Mahaffey, Sullair of Houston   

Bottom Line

Over the course of time, you can expect your air compressor to experience the normal wear and tear of an industrial setting. In order to keep your system functioning effectively, having the knowledge to identify issues and perform routine maintenance can go a long way in prolonging the life of your compressor. If you notice any of these warning signs or a combination of these symptoms, have a technician evaluate your compressor as soon as possible. Prompt inspection and repair can save you money in the long run, since it prevents more costly problems and ensures that a faulty air compressor won’t slow your business down.

An Industrial Air Compressor Maintenance Checklist: 5 Areas Your Technician Should Check

Industrial Air Compressor

In most industrial facilities, an industrial air compressor is an important utility.  It is used for power, process and control throughout all aspects of operation, and is essential for keeping production up and running.  However, unlike other utilities, compressed air is usually generated onsite with user-owned equipment.

While most companies do not produce their own electricity, heat or water, they often own and operate an on-site compressed air system.  Because this utility is vital to a facility’s operation, a thorough preventative maintenance program should be implemented to minimize unexpected downtime resulting from compressor failure.

Every industrial air compressor is configured with a few common components that must be checked and serviced regularly.  A working knowledge of the following five items will enable industrial compressed air users to better understand and maintain their equipment.


Filters are necessary components in all the mechanical systems of an industrial air compressor.  They are installed in the air circuit, lubricant circuit and control circuit to protect against contamination.   Each filter serves a unique and important purpose, and must be cleaned or replaced based on the manufacturer’s recommended intervals and environmental conditions.

Additionally, there are several filters that require regular attention when it comes to lubricated rotary screw compressors.

Air Inlet Filter:

Removes contaminants from inlet air before it enters the compressor.

Lubricant Filter:

Cleans the industrial air compressor’s lubricant – protecting precision metal parts from damage caused by solid contaminants in the oil circuit.

Air/Oil Separator:

Because lubricated rotary screw compressors operate with a flooded compression chamber, an air/oil mixture is discharged from the compressor airend.  Before usable compressed air can be discharged from the compressor package, the air and lubricant must be separated.  The air/oil separator serves this purpose, and is equipped with a replaceable coalescing filter element that should be changed regularly.

Control Line Filters: 

Many industrial air compressors are equipped with pneumatic lines for controlling and sensing various functions during unit operation.  Proper maintenance of control line filters helps to ensure the air compressor is responding appropriately to changes in system demand.


Effective removal and dissipation of heat is an ongoing battle in every industrial air compressor.  The heat of compression must continually be expelled to prevent unsafe operating conditions and machine failure.  In light of this fact, compressor coolers must be regularly inspected and cleaned during routine maintenance.

Air-cooled rotary screw compressors are often equipped with a heat exchanger for the lubricant, and a separate exchanger (aftercooler) for the discharge air stream.  Over time, these coolers will become clogged with dust and other contaminants from the ambient environment.

Water-cooled compressors are usually configured similarly.  However, they use water as a cooling media instead of air.  Cleaning and maintaining water-cooled heat exchangers can be trickier than their air-cooled counterparts, as these units are more subject to corrosion, clogging and leaks.

Additionally, many centrifugal and multi-stage industrial air compressors include inter-stage coolers to reduce temperature between stages of compression.  These coolers must also be checked regularly to identify potential problem areas.


Air compressor lubricants serve a multitude of functions.  In oil-flooded compressors, lubricants are used to remove the heat of compression, seal clearances in the compression chamber, and lubricate bearings.  In compressor motors and gearboxes, separate lubricants are used to reduce friction between components for increased equipment longevity.

Regardless of their purpose, all industrial air compressor lubricants must be selected and maintained properly.  This is one of the most critical maintenance areas for operators of industrial compressed air systems.  Users that neglect to monitor and maintain the condition of their compressor lubricant can cause irreparable damage to their compressed air systems.

Regular oil sampling and analysis can turn a good compressor PM program into a great one.  By analyzing the chemical properties of a compressor’s lubricant, we can spot potential problems before they occur.  At Sullair of Houston, our standard oil sample report highlights many aspects of lubricant condition – like particle count, water content and total acid number.  This allows us to make informed and insightful recommendations to our customers about how to better maintain their equipment.  ~ George Saez, Service Manager Sullair of Houston


Controls are an often misunderstood and overlooked system in industrial air compressors.  However, their impact on the reliability, longevity and efficiency of industrial air systems cannot be understated.

In general, the controls of an industrial air compressor enable it to respond appropriately to changes in system demand.  For example, when system pressure drops, an air compressor should respond by increasing output to offset demand.  When pressure rises, an air compressor should respond by decreasing output to prevent over-pressuring the system.

There are many compressor control types available today – each with a unique set of characteristics and benefits.  However, regardless of type, all compressor control systems consist of several mechanical and electrical components that must be incorporated into the unit PM program.  Potential maintenance items include valves, solenoids, regulators, switches, transmitters, tubing, etc.   If one of these items requires service, the air compressor can operate unpredictably.

Call a trusted compressor service provider for help troubleshooting and repairing control problems.


Most industrial air compressor systems are equipped with several condensate drains.  Often, there are drains installed on compressors, filters, dryers and receiver tanks.  When functioning properly, these drain valves expel liquid water to protect downstream equipment from potential corrosion or damage.  However, if not regularly checked and maintained, a compressed air condensate drain can fail – having a detrimental impact on system performance and reliability.

A drain valve that is stuck in the open position can be a nuisance.  It creates an air leak that reduces system efficiency, or even causes overall pressure to sag.

A drain valve that is stuck in the closed position can often be more problematic – sending liquid slugs of water downstream to overwhelm dryers, filters and pneumatic equipment in the plant.

Many pneumatic control valves used in chemical process and refining applications cost thousands of dollars.  Even a small slug of water can ruin them, and replacement costs are very high.  Protecting these components from liquid water is critical – and a simple, inexpensive maintenance program for compressor condensate drains can help to prevent major failures down the road.  ~ Steve Mahaffey, Sullair of Houston