Tag Archives: Check Valves

Compressor Check Valves: What They Do and Why They Fail

Compressor MaintenanceA compressor’s check valves perform an essential function that’s vital to the operation of a compressed air system. Located between the compressor and the air receiver tank or main header, a check valve is designed to prevent air from bleeding out of the tank or header and back into the inlet line when a compressor shuts down. Unloader valves, meanwhile, allow air to bleed out of the compressor line to reduce load on startup.

A check valve typically consists of a valve mechanism that keeps the header sealed when there is higher pressure in the header than on the compressor side. As a result of this design, a faulty check valve may sometimes leak at lower pressures but not at higher pressures. In fact, leaks can often be traced back to a faulty check valve.

So what happens to compressors when their check valves fail?

In addition to causing leaks, a check valve failure can damage the compressor itself. If a check valve fails in its open position, it can allow air to leak back from the header into the compressor when it’s not running. This, in turn, can cause the compressor to spin backwards, thereby damaging it in the process. More often than not, however, we see check valves fail when they’re closed. When this happens, the stuck valve can cause pressure to increase uncontrollably, ultimately leading to a compressor surge.

The good news is, there are steps you can take to reduce the likelihood of check valve failures in your compressed air system.

To begin with, it’s important to select an appropriately-sized check valve based on the valve’s orientation (vertical or horizontal), your compressor’s flow conditions and type of media (air or another gas). Your compressed air system should also be outfitted with filters to keep compressor lines and check valves free of debris. Finally, be sure to conduct routine maintenance on the system’s valve and compressor lines. This includes flushing the system, disassembling valves to inspect for corrosion and replacing damaged valves if necessary.

At Case Controls, we can help you maintain your compressed air system to prevent check valve failures and other common performance issues. To learn more about the onsite and remote support services we offer, feel free to give us a call at (812) 422-2422 or contact us online today.