Danfoss 90 Series Service Manual

Speed sensors
An optional speed sensor can provide unit speed information. The sensor reads a magnetic ring on the
unit’s cylinder block. See the corresponding section to locate, install, and adjust the speed sensor.
Filtration options
Series 90 pumps may have either suction or charge pressure filtration to filter the fluid entering the
circuit.
The suction filter is in the circuit between the reservoir and the inlet to the charge pump, as shown
below. The use of a filter contamination monitor is recommended.
Suction filtration
Charge pump
Filter
Hydraulic fluid reservoir
Adjustable
charge pressure relief valve
To pump case
To low
loop and
control
Manometer
P102 003E
Suction filtration – option S
The suction filter is in the circuit between the reservoir and the inlet to the charge pump, as shown
below. The use of a filter contamination monitor is recommended.
Charge pressure filtration – option R, T, P, and L
The pressure filter can be mounted on the pump or remotely for ease of servicing. You will typically find a
100-125 µm mesh screen, in the reservoir or the charge inlet. This system requires a filter capable of
withstanding charge pressure (reference to atmosphere - add case pressure).
Charge pressure filtration
To pump case
Charge pump
Hydraulic fluid reservoir
Filter
To low
pressure
side and
control
Screen
Adjustable
charge pressure
relief valve
P102 004E
Pressure override (POR) – 180 frame size only
The Pressure OverRide valve (POR) modulates control pressure to maintain a pump displacement which
produces a system pressure level less than or equal to the POR setting. For unusually rapid load
application, the high pressure relief valve function of the multi-function valves is available to also limit
the pressure level.
The pressure override consists of a three-way normally open valve which operates in series with the
pump displacement control. Control supply pressure normally ports through the POR valve to the
displacement control valve. If the system demands a pressure above the override setting, the POR valve
Service Manual
Series 90 Pumps
Operation
520L0818 • Rev 0101 • August 2015 13

Danfoss 90 Series Specifications

General

Brand	Danfoss
Model	90 Series
Category	Water Pump
Language	English