Longer pump-down times, higher operating temperature, rising base pressure, more noise or vibration, and more frequent unplanned stops. These point to wear or contamination, and how far they have progressed decides between service and replacement.
Longer pump-down times, higher operating temperature, rising base pressure, more noise or vibration, and more frequent unplanned stops. These point to wear or contamination, and how far they have progressed decides between service and replacement.