8. Troubleshooting
PNEG-2174
Sampler - Model GRA
33
Air Components Troubleshooting
Cylinder Leaking
1.
External Leakage
a. Rod seal leakage can generally be traced to worn or damaged seals. Examine the piston rod for
wear or damage. Replace the rod and seals if rod’s surface is rough or worn out-of-round.
b. Soft or gummy seals are evidence of incompatibility with some substance in the air supply.
Evaluate the area where the air intake is located. If an airline lubricator is included in the system,
check to see if the lubricant being used is compatible with the seal material.
2.
Internal Leakage
a. The lipseal piston seals are virtually leak free unless they are worn or damaged. Replace
defective seals.
b. Contaminants in the air supply can lead to scored cylinder walls, resulting in rapid seal wear. If
such is the case, check to see if the filter is being drained frequently. A different type of filter may
be required, one that can remove finer particles or one that can filter out different kinds of
contaminants.
c. Possible piston cylinder leakage, apparently indicated by piston drift is not always traceable to
the piston. A leak through a closed valve port can also cause piston drift.
To determine if a piston is leaking, use a manual override to pressurize one end of the cylinder
in question. When the cylinder has completed its stroke but is still pressurized, carefully remove
the airline from the other cylinder port that presumably is not pressurized. If air can be detected
leaking from the airline connected to the supposedly unpressurized port, then the problem lies
elsewhere in the pneumatic system.
