Danfoss Series 42 Service Manual

High pressure relief valves are available in a range of settings as shown in the model code. The model
code may specify individual pressure settings. The high pressure relief valve settings are referenced to
charge pressure and are set at 3.8 l/min [1 US gal/min] of flow.
High pressure relief valve
High pressure
side of working loop
Charge check and
high pressure
relief valve
Bypass valves
Optional bypass plungers are available for use when it is necessary to move the vehicle or mechanical
function and the prime mover is not running.
Together, these valves connect both sides of the main hydraulic circuit, allowing fluid to circulate without
rotating the pump and prime mover.
The bypass function is integral to the charge check/high pressure relief valve assembly. Depressing the
plunger in the plug of the valve assembly opens the valve. The valve remains open until the prime mover
restarts or pressure builds in the system and causes the valve the close. You must depress the plungers in
both of the check/relief valve assemblies for proper bypass operation.
C
Caution
Bypass valves are for moving a machine or vehicle for very short distances at very slow speeds. They are
not tow valves. If pressure builds within the system, the valves may close causing damage to the pump
and motor or prime mover. Move the vehicle/machine at no more than 20% of top speed for no more
than three minutes.
Charge check and high pressure relief valves with bypass
To/from other
bypass valve
To/from
working loop
Charge check and
high pressure
relief valve
Bypass
plunger
P100394E
Auxiliary mounting pads
SAE A and SAE B auxiliary mounting flanges are available on all Series 42 pumps and are integral to the
charge pump cover. This flange allows mounting of auxiliary hydraulic pumps and mounting of
additional Series 42 pumps to make tandem pumps. The pads allow full through-torque capability.
Service Manual
Series 42 Axial Piston Closed Circuit Pumps
Functional Description
520L0638 • Rev 0300 • July 2015 15

Danfoss Series 42 Specifications

General

Brand	Danfoss
Model	Series 42
Category	Water Pump
Language	English