Danfoss Series 42 Service Manual

Item Description Action
Charge pressure (in neutral) The is low charge pressure resulting
from a damaged charge pump or low
charge pressure relief valve setting.
Inspect the charge pump for damage
and verify the charge pressure relief
valve setting. Repair or replace it as
necessary.
Charge pressure (in stroke) There is low charge pressure resulting
from internal leakage within the
system.
Repair or replace the component or
components within the system causing
the internal leakage.
Servo pressure There is insufficient pressure
differential across the servo piston.
Check servo pressures at port M4 and
M5 to verify sufficient pressure delta.
Verify that the servo supply and drain
paths are unobstructed and that any
orifices are of the correct size and free
of debris. Clean, repair, or replace as
necessary.
Charge pump The charge pump has been damaged
or installed with the incorrect
rotational orientation.
Verify that the charge pump is in good
working order and that it is correctly
installed. Repair or replace it as
necessary.
System will not operate in either direction
Item Description Action
Oil level in reservoir There is insufficient hydraulic fluid to
supply the system loop.
Fill the reservoir to the proper level
with clean hydraulic oil.
Input control signal
(linkage, current, or pressure)
The pump is receiving a faulty control
signal: (MDC - binding or broken
linkage; EDC - faulty or inadequate
electrical signal; HDC - blocked or
incorrectly orificed control lines).
Verify that the input signal is correct
and identical in both directions. Adjust,
clean, repair, or replace the input
device as necessary.
Oil filters Clogged oil filters may result in an
insufficient supply of oil to the system.
Inspect the oil filters and verify that
they are still serviceable. Replace them
as necessary.
Bypass valve A partially activated bypass valve may
result in a cross port leakage.
Verify that the bypass valves are closed
and that the valves are seating
properly. Clean, repair, or replace them
as necessary.
Charge pressure
(in neutral)
Charge pressure may be insufficient to
recharge the system loop.
Inspect the charge pump for damage
and verify that the charge pressure
relief valve is at the proper setting.
Repair or replace it as necessary.
Charge pressure
(in stroke)
There is low charge pressure resulting
from internal leakage within the
system.
Repair or replace the component or
components within the system causing
the internal leakage.
Servo pressure There is an insufficient pressure
differential across the servo piston.
Check servo pressures to verify
sufficient pressure delta. Verify that the
servo supply and drain paths are
unobstructed and that any orifices are
of the correct size and free of debris.
Clean, repair, or replace them as
necessary.
Charge pump The charge pump is damaged or has
been installed with the incorrect
rotational orientation.
Verify that the charge pump is in good
working order and that it is correctly
installed. Repair or replace it as
necessary.
Service Manual Series 42 Axial Piston Closed Circuit Pumps
Troubleshooting
28 520L0638 • Rev 0300 • July 2015

Danfoss Series 42 Specifications

General

Brand	Danfoss
Model	Series 42
Category	Water Pump
Language	English