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MAINTENANCE
MAINTENANCE
The unit should be periodically inspected according to the same items as those described in the
paragraph titled "Test Running". In order to ensure dependable operation and long life, the following
additional items should be given particular attention. Refer to the Hitachi Service Handbook for
Packaged Air Conditioners, if required.
Components
(Condensing Unit)
Compressor - No maintenance work is required for hermetic compressor, if the refrigeration cycle
remains sealed.
Air-Cooled Condenser - Inspect the condenser and remove any accumulated dirt from the coil at
regular intervals. Other obstacles such as growing grass and pieces of paper, which might restrict air flow,
should also be removed.
Electrical Equipment - Always pay careful attention to working voltage, amperage and phase balance.
Check for faulty contact caused by loosened terminal connections, oxidized contacts, foreign matter, and
others.
Safety and Control Devices - Do not readjust the setting in the field unless the setting is maintained at
a point other than the point listed in Table 4.
(Cooling Unit)
Field-Supplied Filter - Inspect for accumulated dirt on the filter, Exchange or clean the filter if required.
The inspection interval may be determined by the operating for each installation site.
Condensate Drain Pan and Drain Line - Inspect and clean the condensate drain line at least twice a
year.
Evaporator Fan - Check for a loosened fan belt and abnormal sounds.
Lubrication
Compressor - The compressors are charged at the factory with the correct oil listed on the compressor
nameplates. It is not necessary to add oil, if the refrigeration cycle remains sealed.
Fan Motor -Bearings of the fan motor are pre-lubricated. Lubrication is not required.
Fan /shaft Bearings - The bearings have been pre-lubricated and sealed at the factory. However, when
the ambient air is dirty and humid, the bearings should be greased from the grease nipple as the
occasion calls.
Refrigerant Cycle
Field-Supplied Liquid Line Sight Glass - Ensure that the sight glass is clear. Flashing seen through
the sight glass indicates that the refrigerant is being charged insufficiently, or that the filter-dryer is
clogged. When low charge is suspected, check the operating pressures, and then add refrigerant or
repair leakage, if necessary.
Filter-Dryer - Check for clogging after the time when the cycle is opened.
Refrigerant Charge - Precautions for new refrigerants R410A is non-azeotrope refrigerant. Therefore,
when the refrigerant leaks, its component's weight percentage will change. Instead of recharging
refrigerant, we should process the system all over again. Evacuate and recharge the cycle according to
the procedures given in "Evacuation and Refrigerant Charge".
NOTES:
1. Do not purge the refrigerant gas from the service joint of the liquid line stop valve, in order to protect
from oil drainage from the refrigeration cycle.
Compressor Removal
When Removing the Compressor,
1. Shut OFF the power supply to the unit.
2. Close all stop valves of the unit.
3. Remove all wiring connections and piping connections to the compressor.
4. Remove the washers on the compressor seat fastened on the base.
5. Slightly lift the compressor, and pull out the compressor from the unit.
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