General Maintenance Procedure For The Indoor Unit - Hitachi YUTAKI Series Installation And Operation Manual

MAINTENANCE

10.1.2 General maintenance procedure for the indoor unit

To ensure good operation and reliability of the indoor unit, main parts and field wiring have to be checked periodically.
The following checks have to be done by qualified technicians at least once a year:
1 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. Tighten the loosened screws and replace the lost screws.
• Insulation material: Check for any peeled thermal insulator on the indoor part of the covers. Repair the thermal insulator.
2 Water piping connection
• Leakage: Check there are no water leakages neither in the inlet and outlet water connections (space heating and DHW if
used), nor in the main water circuit nor the tank connections. Check all the joints, connections and circuit elements.
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N O T E
• If leakage is detected in the inlet/outlet water connections, repair it and remember to replace the gaskets.
• Pay special attention to the water pipe connection placed over the electrical box.
3 Water flow and pressure:
• Water flow:
Space heating: Check the water flow (m
-
Information" menu.
- DHW (if used): Check whether the water circulation is correct along all the DHW circuit.
• Pressure checking:
- Space heating: Check the water pressure using the manometer in the indoor unit (In YUTAKI M units, this manometer is
field supplied). This value shall be between 1.5 and 2.0 bars approximately (1.8 bars is a proper value).
4 Ground wire
• Ground line: Check for the continuity to earth.
5 Yutaki S80 - 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.
6 Yutaki S80 - 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.
7 Yutaki S80 - 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.
8 Yutaki S80 - 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.
9 Yutaki S80 - 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.
151 PMML0510 rev.1 - 10/2019
/h) through the unit controller in the "Heat Pump Details" of the "Operation
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