Danfoss 45 Frame K2 Series, Service Manual

Page: 21 / 40

Item Description Action
Check external system relief valve setting. Fluid passing through relief valve adds heat to
system. Adjust external system relief valve setting
following manufacturer’s recommendations.
External relief valve setting must be above PC
setting for proper operation.
Check PC and LS control setting. Low PC setting will prevent the pump from
achieving full stroke. Low LS setting will limit
output flow.
Adjust PC and LS setting. Refer to Adjustments on
page 23.
Check pump inlet pressure/vacuum. High inlet vacuum adds heat to system. Correct inlet pressure/vacuum conditions.
Check input speed. Low input speeds decrease flow. Adjust input speed.
Check pump rotation. Incorrect rotational configuration will cause low
flow.
Use pump with appropriate rotational
configuration.
Low pump output flow
Item Description Action
Check fluid level in reservoir. Insufficient hydraulic fluid will limit output flow
and cause internal damage to pump. Fill the reservoir to proper level.
Hydraulic fluid viscosity above acceptable limits. Fluid viscosity above acceptable limits or low
fluid temperature will not allow the pump to fill
or control to operate properly.
Allow system to warm up before operating, or
use fluid with the appropriate viscosity grade for
expected operating temperatures. See
Hydraulic
Fluids and Lubricants Technical Information
Manual
, 520L0463.
Check external system relief valve setting. Eternal relief valve set below PC setting causes
low output flow. Adjust external relief valve following
manufacturer’s recommendation. External relief
valve setting must be above PC setting to
operate properly.
Check PC and LS control setting. Low PC setting prevents the pump from
achieving full stroke. Adjust PC and LS setting. Refer to the
Adjustments chapter.
Check pump inlet pressure/vacuum. High inlet vacuum causes low output flow. Correct inlet pressure conditions.
Check input speed. Low input speeds decrease flow. Adjust input speed.
Check pump rotation. Incorrect rotational configuration causes low
flow. Use pump with appropriate rotational
configuration.
Pressure or flow instability
Item Description Action
Check for air in system. Air in system causes erratic operation. Activate PC allowing system to bleed air. Check
inlet line for leaks and eliminate source of air
ingression.
Check control spools. Sticking control spools cause erratic operation. Inspect spools for free movement in bore. Clean
or replace.
Check LS setting. Low LS setting may cause instability. Adjust LS setting to proper level. See the
Adjustments chapter.
Check LS signal line. Blocked LS signal line interferes with proper LS
operation. Remove blockage.
Check external relief valve and PC setting. Insufficient pressure differential between PC
setting and external relief valve. Adjust external relief valve or PC control settings
to appropriate level. Relief valve setting must be
above PC setting to operate properly.
Check external relief valve. Chattering external relief valve may cause
unstable feedback to pump control. Adjust or replace relief valve.
Service Manual
Series 45 Frame K2 Open Circuit Axial Piston Pumps
Troubleshooting
© Danfoss | April 2017 AX00000301en-US0101 | 21