Maintenance; Maintenance Work; General Maintenance Procedure For The Outdoor Unit - Hitachi YUTAKI Series Installation And Operation Manual

MAINTENANCE

10 MAINTENANCE

10.1 MAINTENANCE WORK

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C A U T I O N
• All inspections and checks have to be carried out by a licensed technician and never by the user itself.
• Before any inspection and check the unit main power supply has to be switched OFF.
• Wait a minimum off 10 minutes from all power supply have been turned OFF.
• Take care with the crankcase heater. It could operate even when compressor is OFF.
• Take care with the electrical box components. Some of them could remain hot after switching OFF the unit.
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N O T E
All these maintenance operations must be done with appropriate materials and following this manual.

10.1.1 General maintenance procedure for the outdoor unit

1 Fan and fan motor
• Lubrication: All the fan motors are pre-lubricated and sealed at factory. Therefore no lubrication maintenance is required.
• Sound and vibration: Check for abnormal sounds and vibrations.
• Rotation: Check the clockwise rotation and the rotating speed.
• Insulation: Check the electrical insulation resistance.
2 Heat exchanger
• Clog: Inspect the heat exchanger at regular intervals and remove any accumulated dirt and any accumulated dust from the
heat exchanger. Other obstacles must be removed such as the growing grass and the pieces of paper which might restrict
the airflow.
3 Refrigerant piping connection
• Leakage: Check for the refrigerant leakage at the piping connection between the outdoor and the indoor unit.
• Pressure: On split system, check the refrigerant pressure using the check joints of the outdoor unit.
4 Cabinet
• Stain: Check for any stain and remove it cleaning if it is the case.
• Fixing screw: Check for any loosened screw or any lost screw. Fix the loosened screws and the lost screws.
• Insulation material: Check for any peeled thermal insulator on the cabinet. Repair the thermal insulator.
5 Electrical equipment
• Activation: Check for an abnormal activation of the magnetic contactor, the auxiliary relay, the PCB and others.
• Line condition: Pay attention to the working voltage, the working amperage and the working phase balance. Check for any
faulty contact that is caused by the loosened terminal connections, the oxidized contacts, the foreign matter and other items.
Check the electrical insulation resistance.
6 Control device and protection device
• Setting: Do not readjust the setting in the field unless the setting is maintained at a point that is different from the point listed
in the Technical Documentation.
7 Compressor
• Sound and vibration: Check for abnormal sounds and vibrations.
• Activation: Check that the voltage drop of the power supply line is within 15% at the start and within 2% during the operation.
8 Reverse valve
• Activation: Check for any abnormal activation sound.
9 Strainer
• Clog: Check that there is no temperature difference between both ends.
10 Ground wire
• Ground line: Check for the continuity to earth.
11 Oil heater (Crankcase heater of the compressor)
• Activation: The oil heater should be activated at least twelve hours before the start-up by turning ON the main switch.
150 PMML0510 rev.1 - 10/2019