How to Fix Low Exhaust Pressure in Oil-Free Air Compressors

An oil-free air compressor is designed to provide clean, compressed air for various industrial and commercial applications. However, users may sometimes face the issue of insufficient exhaust pressure. When this happens, the compressor cannot discharge enough air to meet the required flow rate, leading to operational inefficiencies. In this article, we’ll explore common causes of insufficient exhaust pressure in oil-free air compressors and provide troubleshooting tips to help you resolve the issue.

Causes of Insufficient Exhaust Pressure in an Oil-Free Air Compressor

Several factors can cause the exhaust pressure of an oil-free air compressor to drop below the required levels. Below are the most common causes:

1. Faulty Barometer

The first step in diagnosing pressure issues is to check the barometer. If the barometer is faulty, it may show incorrect pressure readings, making it seem like the air pressure is insufficient when it is not.

2. Loose Transmission Belt

The transmission belt between the air compressor and the engine plays a critical role in maintaining adequate pressure. If the belt is too loose or slippery, it may fail to transmit the required power, resulting in low air pressure. Additionally, if the pipeline between the air compressor and the air tank is broken or the gasket is leaking, pressure may drop.

3. Blocked Air Filter or Oil-Water Separator

A clogged oil-water separator, pipeline, or air filter can severely restrict airflow, leading to insufficient exhaust pressure. Excessive sediment build-up is often the root cause of these blockages.

4. Exhaust Valve Issues

If the air compressor’s exhaust valve blade is not sealing correctly, or if the valve spring is too soft or broken, the compressor will struggle to maintain sufficient pressure. Loose cylinder head bolts or damaged cylinder head gaskets may also contribute to pressure leakage.

5. Worn Cylinder Liner, Piston, or Piston Ring

Wear and tear on critical components like the cylinder liner, piston, or piston ring can lead to air leakage. As these parts wear down over time, they become less effective at maintaining pressure, ultimately causing low exhaust pressure.

How to Troubleshoot and Fix Insufficient Pressure

Identifying and addressing the causes of low exhaust pressure in your oil-free air compressor requires a systematic approach. Below are steps to help troubleshoot the issue:

1. Check the Barometer

First, observe the pressure gauge. If the pressure is insufficient even after letting the engine run at medium speed for a few minutes, the barometer may be faulty. To confirm, press the brake pedal. If you hear a loud deflation sound, this indicates the air pressure gauge is damaged and needs repair.

2. Inspect for Leaks

Leaks in the system can result in significant pressure loss. If no deflation sound is heard during the barometer test, check the air compressor belt for looseness. Also, inspect the entire pipeline, from the air compressor to the air tank, for broken pipes or loose gaskets. Any broken or leaking components should be repaired or replaced.

3. Clean the Oil-Water Separator and Air Filter

If the air tank is not being charged, examine the oil-water separator, air filter, and pipelines for excessive dirt or sediment build-up. Clean or replace the filter and separator if necessary to restore proper airflow.

4. Listen for External Leaks

Start the oil-free air compressor and stop it when the air tank reaches a certain pressure. Use your ears to listen for any air leaks coming from external pipes, one-way valves, safety valves, or the pressure switch. If a leak is detected, repair it immediately to prevent further pressure loss.

5. Check for Excessive Air Demand

Sometimes, the issue may not lie with the air compressor itself but with your air demand exceeding the compressor’s capacity. If you have recently added new equipment or processes that require more air, the compressor may be unable to keep up, causing pressure to drop. In such cases, consider upgrading to a larger compressor to meet the increased demand.

6. Examine the Compressor Head Scalp Cup

If none of the above solutions work, the compressor head scalp cup may be worn. Typically, this part has a shelf life of about three years. If it is worn, it should be replaced to restore proper pressure levels.

Conclusion

An oil-free air compressor can experience insufficient exhaust pressure for a variety of reasons, including faulty components, blockages, and air leaks. Identifying the root cause of the problem is essential to restoring proper pressure levels and ensuring optimal compressor performance. By following the troubleshooting steps outlined in this article, you can effectively diagnose and resolve issues with your oil-free air compressor, preventing costly downtime and maintaining productivity.

For persistent problems or if you’re unsure how to resolve the issue, it’s always a good idea to contact a professional technician. Regular maintenance and timely repairs will extend the life of your compressor and keep it running at peak efficiency.

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