System Operating Hot; Low Pump Output Flow; Pressure Or Flow Instability - Sauer Danfoss 45 Series Service Manual

system oPeRating Hot

Low PumP outPut
fLow
PRessuRe oR fLow
instabiLity
Series 45 G Frame Open Circuit Axial Piston Pumps
Service Manual
Troubleshooting
item
Check fluid level in reservoir.
Inspect heat exchanger. Check air
flow and input air temperature for
the heat exchanger.
Check external system relief valve
setting.
Check pump inlet pressure /
vacuum.
item
Check fluid level in reservoir.
Hydraulic fluid viscosity above
acceptable limits.
Check external system relief valve
setting.
Check PC and LS control setting.
Check pump inlet pressure /
vacuum.
Check input speed.
Check pump rotation.
item
Check for air in system.
Check control spools.
520L0605 • Rev AB • December 2010
Description
Insufficient volume of hydraulic
fluid will not meet cooling
demands of system.
Insufficient air flow, high input air
temperature, or undersized heat
exchangers will not meet cooling
demands of the system.
Fluid passing through relief valve
adds heat to system.
High inlet vacuum adds heat to
system.
Description
Insufficient hydraulic fluid will limit
output flow and cause internal
damage to pump.
Fluid viscosity above acceptable
limits or low fluid temperature
will not allow the pump to fill or
control to operate properly.
Eternal relief valve set below PC
setting causes low output flow.
Low PC setting prevents the pump
from achieving full stroke.
High inlet vacuum causes low
output flow.
Low input speeds decrease flow.
Incorrect rotational configuration
causes low flow.
Description
Air in system causes erratic
operation.
Sticking control spools cause
erratic operation.
action
Fill reservoir to proper level. Verify
proper size of reservoir.
Clean, repair, or replace heat
exchanger as required. Verify
proper size of heat exchanger.
Adjust external system relief valve
setting following manufacturer's
recommendations. External relief
valve setting must be above PC
setting for proper operation.
Correct inlet pressure / vacuum
conditions.
action
Fill the reservoir to proper level.
Allow system to warm up before
operating, or use fluid with the
appropriate viscosity grade for
expected operating temperatures.
See Hydraulic fluids, Series 45
Technical Information Manual,
520L0519.
Adjust external relief valve
following manufacturer's
recommendation. External relief
valve setting must be above PC
setting to operate properly.
Adjust PC and LS setting. Refer to
Adjustment, page 21.
Correct inlet pressure conditions.
Adjust input speed.
Use pump with appropriate
rotational configuration.
action
Activate PC allowing system
to bleed air. Check inlet line for
leaks and eliminate source of air
ingression.
Inspect spools for free movement
in bore. Clean or replace.
19