Excessive Noise and /or Vibration
Item
Description
Action
Check fluid level in reservoir.
Insufficient hydraulic fluid causes
cavitation.
Fill the reservoir to proper level.
Check for air in system.
Air in system causes noisy, erratic
control.
Purge air and tighten fittings. Check
inlet for leaks.
Check pump inlet pressure / vacuum. Improper inlet conditions cause
erratic behavior and low output flow.
Correct pump inlet pressure /
vacuum conditions.
Inspect shaft couplings.
A loose or incorrect shaft coupling
causes excessive noise and / or
vibration.
Repair or replace coupling and
ensure that correct coupling is used.
Check shaft alignment.
Misaligned shafts create excessive
noise and / or vibration.
Correct shaft misalignment.
Hydraulic fluid viscosity above
acceptable limits.
Hydraulic 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.
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.
Check external system relief valve
setting.
External 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 pressure compensate (PC),
load sensing (LS) and power (T)
control setting.
Low PC setting prevents the pump
from achieving full stroke. Low LS
setting limits output flow. Low T
setting limits output flow.
Contact Danfoss Service.
Check LS control signal pressures.
Incorrect LS signal will not allow
pump to operate correctly.
Inspect system to ensure that proper
LS signal transmit to pump.
Check Pilot pressure for hydraulics
displacement control and input
current for electric displacement
control.
Incorrect input signal causes low
output flow.
Adjust input hydraulic or electric
signal to right value.
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.
No or Low System Pressure
Item
Description
Action
Check pressure compensate (PC) and
power (T) control setting.
Low PC and T setting leads to low
system pressure.
Contact Danfoss Service.
Check external relief valve.
External relief valve setting below PC
setting.
Adjust external relief valve according
to manufacturer’s recommendations.
External relief valve must be set
above PC setting to operate properly.
Service Manual
D1 High Power Open Circuit Pumps Size 65/130/145/193/260
Troubleshooting
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©
Danfoss | July 2019
L1527453 | AX00000292en-CN0201