System Operating Hot; High Inlet Vacuum - Danfoss D1 Series Service Manual

Service Manual
D1 High Power Open Circuit Pumps Size 65/130/145/193/260
Troubleshooting

System Operating Hot

High Inlet Vacuum

34 | © Danfoss | July 2019
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. High inlet vacuum adds heat to
Item
Check fluid temperature.
Inspect inlet screen.
Check inlet piping.
Hydraulic fluid viscosity above
acceptable limits.
C
Caution
High inlet vacuum causes cavitation which can damage internal pump components.
Descriptin
Insufficient volume of hydraulic fluid
will not meet cooling demands of
system.
Insufficient air flow, high input air
temperature, or undersized heat
exchanges will not meet cooling
demands of the system.
Fluid passing through relief valve
adds heat to system.
system.
Description
Low temperature increases viscosity.
High fluid viscosity causes high inlet
vacuum.
Blocked or restricted inlet screen
causes high inlet vacuum.
Too many fittings, bends, or long
piping causes high inlet vacuum.
High fluid viscosity causes high inlet
vacuum.
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
Allow system to warm up before
operating.
Clean screen / remove blockage.
Eliminate fittings to make path more
direct.
Select fluid with appropriate viscosity
for expected operating temperature.
L1527453 | AX00000292en-CN0201