Daikin Super Unit Manual Guide: Installation, Hydraulic Piping, Electrical Wiring, Filter, Regenerative Resistor, Pressure Sensor, Pump Replacement and Maintenance Diagnosis

Why Installation and Maintenance Matter

Many Daikin Super Unit faults do not come from the controller board itself. Common causes include poor cooling space, bad suction piping, weak grounding, incorrect filter wiring, pressure sensor cable vibration, hot regenerative resistor and missing calibration after pump replacement. This guide focuses on installation, wiring, maintenance and recalibration.

Mounting, Cooling and Fixing

Leave sufficient cooling space around the controller and motor pump. The manual recommends at least 100 mm clearance. Do not block the motor cooling fan. The motor pump must be fixed firmly because hydraulic reaction force and startup shock can move it.

If the suction port direction is changed, follow the manual procedure. Do not hammer the pump shaft or force the port; damaged spline, shaft or seal surface will later cause noise, leakage, heat and reduced flow.

Hydraulic Piping

The Super Unit does not include a safety valve. Install one on the machine side and set it around maximum operating pressure plus 2 MPa. Avoid inappropriate straight check valves on the discharge side because they may prevent controlled pressure release. Accumulator circuits need backflow protection to prevent reverse pump rotation after power off.

Install a suction filter of about 150 mesh and keep suction pressure within -0.02 MPa. Low suction pressure causes air intake, cavitation noise, reduced flow and pressure pulsation.

Electrical Wiring

Main terminals include L1/L2/L3 power input, U/V/W motor output, P1/P2 DC reactor and B1/B2 regenerative resistor. Use correct wire size, crimp terminals and torque. Power cable and motor cable must never be connected to I/O terminals.

I/O terminals handle analog commands, monitor outputs, alarm contacts, digital I/O, pressure sensor and encoder signals. Keep analog and sensor cables away from U/V/W and contactor coils. Ground shields correctly.

Filter, Grounding and Noise Control

Use an input filter to suppress noise. The filter body must have good metal contact with the cabinet. Keep input and output cables separated; do not bundle them or route them in the same duct. Poor grounding or parallel filter wiring can cause random alarms, monitor noise and PLC input errors.

Regenerative Resistor and DC Reactor

P1/P2 are used for the DC reactor. B1/B2 are used for the regenerative resistor. Regenerative energy appears during deceleration, load-driven rotation or hydraulic backflow. Install the resistor on a ventilated metal surface and prevent accidental touch. Wrong resistor value, capacity or wiring can lead to overvoltage or controller damage.

Pressure Sensor and H30

The pressure sensor is the core of pressure feedback. Install the ferrite core near the controller side of the sensor cable, around 100 mm from the terminal, with two turns. Fix the cable near the sensor so pump vibration does not pull the connector.

After replacing the pressure sensor, set H30 PS_G. Power up after pressure is released so zero point can be corrected, then calibrate with an accurate pressure gauge.

Pump Replacement, H15 and P07

After pump replacement, H15 Q_EV or P07 QMAX may need adjustment. Use monitor mode to observe Qo and compare with metering action, cylinder speed or measured flow. Do not blame parameters before checking suction pipe, filter, oil condition, leakage and valve resistance.

Preventive Service

Record oil temperature, noise, suction filter condition, fan status, Po/Qo monitor values, alarm history and high-pressure duty time. High oil temperature, dirty oil, suction leak and blocked filter often look like parameter problems but are hydraulic-condition problems.

Recommended delivery order: fixing and cooling, safety valve, suction pressure, filter grounding, main terminals, I/O analog signals, pressure sensor fixing, regenerative resistor cooling, low-pressure bleeding, PMAX/QMAX calibration, H30/H15 check and full-cycle machine test.