Hitachi RAC-25YH4, Service Manual, Page: 5 / 121

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1. In quiet operation or stopping the running, slight flowing noise of refrigerant in the refrigerating cycle is
heard occasionally, but this noise is not abnormal for the operation.
2. When it thunders near by, it is recommend to stop the operation and to disconnect the power cord plug from
the power outlet for safety.
3. The room air conditioner does not start automatically after recovery of the electric power failure for prevent-
ing fuse blowing. Re-press START/STOP button after 3 minutes from when unit stopped.
4. If the room air conditioner is stopped by adjusting thermostat, or missoperation, and re-start in a moment,
there is occasion that the cooling and heating operation does not start for 3 minutes, it is not abnormal and
this is the result of the operation of IC delay circuit. This IC delay circuit ensures that there is no danger of
blowing fuse or damaging parts even if operation is restarted accidentally.
5. This room air conditioner should not be used at the cooling operation when the outside temperature is
below 10°C (50°F).
6. This room air conditioner (the reverse cycle) should not be used when the outside temperature is below
–10°C (14°F).
If the reverse cycle is used under this condition, the outside heat exchanger is frosted and efficiency falls.
7. When the outside heat exchanger is frosted, the frost is melted by operating the hot gas system, it is not
trouble that at this time fan stops and the vapour may rise from the outside heat exchanger.
! CAUTION
RAS_25_35_AW_001-024 2003.12.31, 10:43 AM 3