For a hydraulic piston pump, pay particular attention to housing filling and the case-drain connection. Check that the model and its controls suit the circuit type; matching displacement alone does not establish compatibility.
Installation and initial start-up are essential to hydraulic unit reliability. A correct replacement involves checking the mechanical mounting, oil supply and circuit settings before applying a load. These general instructions complement the manufacturer’s documentation; they do not replace the procedure for the machine or the specific model being installed.
Before installing the unit
The work should be carried out by personnel who understand the hydraulic system. If installation or replacement is beyond your experience, obtain qualified technical assistance. Have the unit documentation available and check that the oil, operating conditions and connections are suitable for the complete system.
Cleanliness, oil and filtration
The oil must be clean and suitable for the unit and the system’s operating temperature range. Clean the inside of the reservoir and inspect the pipes, fittings and seals. Replace the relevant filters and replenish with clean oil. Contamination or trapped air introduced during installation can also damage a new unit.
Mechanical mounting and hydraulic connections
Check the required direction of rotation and its compatibility with the drive. Align the coupling correctly and avoid axial or radial shaft loads that the manufacturer does not permit. Size pipes, hoses, fittings and accessories for the circuit’s maximum flow; avoid unnecessary elbows and excessively tight bends.
Where the installation permits, flexible connections help limit the transmission of vibration. Connections must remain leak-tight: check for both oil leakage and air entering the circuit. A restricted inlet or an air leak must be investigated before proceeding with start-up.
Install the pump with the case-drain port uppermost and route the line directly to the reservoir, discharging below the oil level, as specified for the model. Avoid restrictions in the drain that could compromise correct housing filling.
Filling and bleeding the circuit
Before starting the piston pump, fill its housing through the upper case-drain port, bleed screw and inlet or outlet connections specified by the manufacturer. The housing must be properly primed; do not start operation with an empty case.
Bleed the complete system, including the unit, the associated pump or motor, pipes and other components, in accordance with the machine procedure. Filling the reservoir alone does not remove air from the circuit. Check the oil level after filling the components and readjust it as instructed.
Initial start-up
Unload the circuit and reduce the relief-valve pressure to the minimum setting specified for commissioning. Run the unit initially without load, at minimum speed and at zero or minimum pressure, as permitted by the manufacturer. Continue for several minutes, then increase speed and pressure gradually to the recommended operating conditions.
Checks after starting
Observe operation before applying the normal machine load. Check for leaks and inspect connections, oil level, temperature, vibration and abnormal noise. On the inlet side, make sure air is not being drawn in and check for bubbles in the reservoir. If an abnormal condition appears, stop commissioning and identify the cause before continuing.
Keep a record of the unit reference and final operating settings. Drainage, mounting, fluid and start-up requirements can vary between models; always consult the relevant technical documentation and follow the manufacturer’s required procedures. Contact Hidraoil for help checking a reference or preparing a replacement.
