General Alarm Limits for Hydraulic Systems

Contamination is the most serious concern to hydraulic systems, and they must be monitored periodically. dirt and water are the most serious contaminants. It is estimated that 75 to 85% of all hydraulic system failures are a direct result of fluid contamination. Components such as pumps, valves, actuators and conductors are affected by contamination in the following ways:

1. Increased internal leakage which lowers pump and motor efficiencies and reduces ability of valves to control flow and pressure accurately. This wastes horsepower and generates excess heat.
2. Corrosion of the system from acids that form due to fluid oxidation and water contamination
3. Silt locking of valves due to particle contamination.

Guidelines for determining if a hydraulic fluid is unsuitable for service are listed here. Filtration and/or water removal is recommended when analysis alarms on particle count or water respectively.