How Flow Control Will Fix Your Stuttering Pneumatic Cylinder

Leaking Manifold Valves? Let’s Troubleshoot It

Example of leaking exhaust port on an air supply port

What’s Leaking?

While running an automated assembly machine, a machine operator notices air leaking from the exhaust port of a 5-station valve manifold. Their maintenance technician later confirms that compressed air is consistently leaking from one of the exhaust ports of the manifold.

Even after turning the main air off and on when replacing each valve, the air is still leaking from the valve manifold. Why is the valve manifold leaking from the exhaust port?

Detecting the Air Leak

99.9% of the time, if air leaks from a valve or air valve manifold, it is because you have a bad seal on an air cylinder or rotary actuator.

With a worn or damaged piston seal (1), the compressed air holding the air cylinder in the retracted position leaks. The leaking air goes past the piston seal into the rear area of the cylinder (2) through the air valve and exits through the exhaust port (3).

This method is the best way to figure out if the valve is bad or if a piston seal is defective, especially if you have a large manifold with several pneumatic actuators on the machine. Using needle nose pliers, pin the tubing to each air cylinder. Start on one end of the manifold and continue this method until the air is no longer leaking. Once it stops, you've found your problem.

If problems continue to arise, contact Motion Automation Intelligence for help today to set up a consultation.