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Maintenance
7. Maintenance
The unit should be periodically inspected according to the same items as those described in the paragraph
entitled "Test Running". To ensure dependable operation and long life, the following additional items should be
given particular attention.
7.1 Components
(Outdoor Unit)
(1) Compressor – No maintenance work is required for hermetic compressor if the refrigeration cycle
remains sealed.
(2) 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.
(3) 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 matters and
others.
(4) 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 .
(Indoor Unit)
(5) Air Filter – Inspect for accumulated dirt on the filter. Change or clean the filter if required. The
inspection interval may be determined by the operating conditions for each installation site.
(6) Condensate Drain pan and Drain Line – Inspect and clean the condensate drain line at least twice a year.
(7) Evaporator Fan – Check for loosened fixed screw and abnormal sounds.
(8) Operate Panel – Check for abnormal function.
7.2 Lubrication
Compressor – The compressors are charged at the factory with the correct quantity of oil listed on the compressor
nameplates. It is unnecessary to add oil if the refrigeration cycle remains sealed.
Fan Motor – Bearings of fan motor are pre-lubricated. Lubrication is not required.
7.3 Refrigerant Charge
When the refrigeration cycle requires recharging due to leakage or part replacement, follow the procedures given
below for two cases:
1. When the refrigeration cycle completely leaked, evacuate, and recharge the cycle according to the procedures
given in "Evacuation and Refrigerant Charge".
2. When the refrigeration cycle slightly leaked, evacuation may not be required. Refrigerant addition can
be performed by liquid charging the service joint of the unit while operating the entire system. Slowly
charge refrigerant into the refrigeration cycle, checking the discharge and suction pressure.
NOTE:
Do not purge the refrigerant gas from the service joint of the liquid line stop valve to prevent the oil from
draining from the refrigeration cycle.
7.4 Compressor Removal
When removing the compressor:
(1) Shut off the power supply of the unit.
(2) Close all the unit stop valves, gas inlet and liquid outlet valves.
(3) Remove all wiring connections and piping connections to the compressor.
(4) Remove refrigerant.
(5) Remove the bolts fastened on the compressor base.
(6) Pull out the compressor base.
(7) Slightly lift the compressor and pull the compressor from the unit.
7.5 Start-Up After Extended Shutdown
After any extended period of shutdown, prepare the unit for operation as follows:
(1) Thoroughly inspect and clean the unit.
(2) Clean or replace the air filter.
(3) Clean the condensate drain lines.
(4) Remove any accumulated dirt from the condenser and evaporator coils.
(5) Check the fan screw tightness.
(6) Check the fan balance and try to operate the fan.
(7) Inspect the refrigerant piping for leakage.
(8) Tighten all wiring connections and access panels.
7.6 Replacement of Parts
Replacement of parts should be performed by ordering from the HITACHI Parts List. The Form A HITACHI
Recommended Spare Parts List is advisable. When replacement of parts becomes necessary, prepare the parts
shown in the Form A Parts List.
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