General Maintenance Procedure For The Indoor Unit - Hitachi YUTAKI Serie Installations- Und Betriebshandbuch

MAINTENANCE
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 R410A 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 R-410A compressor)
• Activation: The oil heater should be activated at least twelve hours before the start-up by turning ON the main switch.

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).
175 PMML0335A rev.1 - 04/2016
/h) through the unit controller in the "Heat Pump Details" of the "Operation
3