1. Low fluid level
2. Fluid too heavy ( incorrect viscosity )
3. Fluid temperature too low
4. Suction line too small
5. Restriction or partially clogged suction line
6. Suction strainer / filter contaminated
7. Suction strainer / filter too small
8. Pump running too fast
9. Reservoir air-vent plugged
10. Air bubbles in fluid
11. Air leak at pump inlet plumbing
12. Flexible coupling misalignment
13. Pump excessively worn

B)  Pump Takes Too Long To Respond Or Fails to Respond

1. Low fluid level
2. Fluid too heavy ( incorrect viscosity )
3. Suction strainer / filter contaminated
4. Suction strainer / filter too small
5. Suction ball valve closed or partially closed
6. Reservoir air-vent plugged
7. Air leak at pump inlet plumbing
8. Pump running too slowly
9. Pump failure

C)  No Pressure In System

1. Pump not delivering fluid ( See A or B above )
2. Relief valve mal-adjusted or failed ‘open’
3. Internal leakage in control valves, motors or cylinders
4. External leakage of component(s)

D)  Low Or Erratic Pressure In System

1. Relief valve setting too low
2. Relief valve worn or sticking
3. Low fluid level
4. Fluid too heavy ( incorrect viscosity )
5. Air bubbles in fluid
6. Control valves not opening / closing fully
7. Internal leakage in control valves, motors or cylinders
8. External leakage of component(s)
9. Pump compensator setting too low
10. Pump excessively worn

E)  Slow Or No Actuator Operation

1. Pump not delivering correct amount of fluid ( See A or B above )
2. Directional Control not shifting
   a. Electrical failure of solenoid, limit switches, etc
   b. Insufficient pilot-pressure
   c. Interlock device not actuated
3. Worn or damaged cylinder or hydraulic motor
4. Flow control mal-adjusted
5. Operating pressure too low
6. Mechanical bind

 F)  Excessive Heating Of Fluid

1. Continuous operation at relief valve setting
2. Pump compensator set higher than relief valve
3. Components leaking internally
4. Reservoir sized too small to provide adequate heat rejection
5. Fluid level low or insufficient
6. Valves or plumbing too small
7. Fluid viscosity too low
8. Heat exchanger water shut off or heat exchanger plugged