Danfoss Series 40 M46 Service Manual

Item Description Action
Oil filters Clogged oil filters may result in an insufficient
supply of cool oil to the system.
Inspect the oil filters and verify that they are still
operable. Replace them if necessary.
Machine load Excessive loads or extreme duty cycles can result in
the pump and/or motor operating at speeds and
pressures beyond system design limitations.
Verify that the machine is operating within the
parameters for which it was designed. If necessary,
reduce the load on the machine.
System will not operate in one direction
Item Description Action
Input control signal (linkage, current, or
pressure)
A faulty control signal is being received at the
pump. (MDC - binding or broken linkage, EDC -
faulty or inadequate electrical signal, HDC -
blocked or incorrectly orificed control lines).
Verify that the input signal being received is
correct and identical in both directions. Adjust,
clean, repair, or replace the control module as
necessary.
Displacement limiters (if equipped) The displacement limiters may be improperly
adjusted such that the servo piston is prevented
from moving in one direction.
Verify that the displacement limiters are adjusted
properly.
SCR (system check / relief) valves The SCR valves are malfunctioning or improperly
set.
Verify that the SCR valves are operating properly.
Repair or replace them as necessary.
Pump control A damaged or biased pump control may be
sending a signal commanding the pump to stroke
only in one direction.
Verify that the pump’s control is functioning
properly. Repair or replace it as necessary.
Servo pressure The drain or supply path to one side of the servo
piston may be blocked.
Verify that the servo supply and drain paths are
unobstructed and that each orifice is of the correct
size and free of debris. Clean or repair them 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.
Displacement limiters Displacement limiters may be improperly adjusted
such that the servo piston is locked in place.
Verify that the displacement limiters are adjusted
to the proper setting.
Input control signal
(linkage, current, or pressure)
A faulty control signal being received at the pump.
(MDC - binding or broken linkage, EDC - faulty or
inadequate electrical signal, HDC - blocked or
incorrectly orificed control lines)
Verify that the input signal being received 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 (one or both)
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 each orifice is of the
correct size and free of debris. Clean, repair, or
replace them as necessary.
Service Manual
Series 40 M46 Variable Pumps
Troubleshooting
©
Danfoss | September 2017 11026743 | AX00000027en-US0202 | 15

Danfoss Series 40 M46 Specifications

General

Brand	Danfoss
Model	Series 40 M46
Category	Water Pump
Language	English