| 摘要 |
PURPOSE:To certainly change four-way valve, as well as to prevent frost in an air-conditioning machinery room, and to obtain comfortable humidity even in the time when air heating operation is stopped, by performing dehumidifying operation for a predetermined time after air heating operation is stopped, and by operating a variable-frequency compressor above the specified frequency range for a predetermined time at the beginning of dehumidifying operation. CONSTITUTION:When an air heating operation stopping signal is outputted from an air heating operation stopping signal generator 22, a pilot solenoid- operated valve 8 is deenergized at the same time the operation of a humidifier 21 is stopped. At this time, a compressor 1 is operated by a frequency controller 14 above the specified frequency range for a predetermined time. By this operation, a bypass for gas through the pilot solenoid-operated valve 8 is cut off, though the port 8B of a valve 8 is held in the open state. Accordingly, difference is produced in the pressure between the right and the left sides of a sliding part 9G, and the valve 8 is completely switched to the left side to start dehumidifying operation.
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