Danfoss Series 42 Service Manual

Overview
This section provides general steps to follow if you observe certain undesirable system conditions. Some
of the items are system specific. Always observe the safety precautions listed in the introduction of this
manual. If standard troubleshooting procedures do not remedy the problem, contact a Danfoss Global
Service Partner.
System operating hot
Item Description Action
Oil level in reservoir Insufficient hydraulic fluid will not
meet the cooling demands of system.
Fill the reservoir to the proper level
with clean hydraulic oil.
Heat exchanger (if equipped) The heat exchanger is not sufficiently
cooling the system.
Check the air flow and input air
temperature for the heat exchanger.
Clean, repair, or replace the heat
exchanger as necessary.
Bypass valve A partially activated bypass valve may
result in heat generation within the
system.
Verify that the bypass valve is fully
closed and that the valve is seating
properly. Repair or replace it as
necessary.
SCR (System Check / Relief) Valves A partially activated SCR valve or SCR
valves with relief settings too low may
result in heat generation within the
system.
Verify that the SCR valve is seating
properly and is at the correct relief
setting. Repair or replace it as
necessary.
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
could 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 response is sluggish
Item Description Action
Reservoir oil level There is an insufficient amount of
hydraulic fluid, resulting in an
inadequate supply for the system loop.
Fill the reservoir to the proper level
with clean hydraulic fluid.
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.
Pump control A damaged pump control or control
spool will not correctly transmit the
control input signal to the pump.
Verify that the pump’s control is
operating properly and that the
control spool is not damaged or worn
and moves freely within its bore. Clean,
repair, or replace it as necessary.
Bypass valve A partially activated bypass valve will
cause cross port leakage.
Verify that the bypass valve is closed
and that the valve is seating properly.
Clean, repair, or replace it as necessary.
SCR (system check / relief) valves One or both of the SCR valves may be
binding within their bores.
Verify that the SCR valves operate
freely. Repair or replace them as
necessary.
Service Manual Series 42 Axial Piston Closed Circuit Pumps
Troubleshooting
520L0638 • Rev 0300 • July 2015 27

Danfoss Series 42 Specifications

General

Brand	Danfoss
Model	Series 42
Category	Water Pump
Language	English