Air conditioner apparatus with starting control for parallel operated compressors based on high pressure detection

Claim 1

A multi-type air-conditioner apparatus comprising: an outdoor unit comprising at least two compressors, at least one of said compressors being a variable-capacity compressor, and an outdoor heat exchanger coupled to said two compressors; a plurality of indoor units each including at least one heat exchanger and means for outputting required capacity data in accordance with an air-conditioning load, for at least a heating operation, of said indoor heat exchanger; a distribution unit for parallel-coupling said plurality of indoor units to said outdoor unit to form a plurality of refrigeration cycles for at least said heating operation, said distribution unit including a plurality of refrigerant flow rate control means for the respective refrigeration cycles; pressure detecting means for detecting a high-pressure-side pressure of the refrigeration cycle; first control means for supplying flow rate control commands to said refrigerant flow rate control means of said distribution unit, respectively, in accordance with said required capacity data for said heating operation from said plurality of indoor units, and for controlling a number of said compressors to be driven and an operating frequency of said variable-capacity compressor in accordance with a sum of the required capacity data; second control means for sequentially starting said two compressors at intervals to shorten a rising time of said heating operation and controlling said compressors in a parallel operation state for a predetermined period of time regardless of the required capacity data when the heating operation is started; and third control means comprising: means for fetching pressure data from said pressure detecting means and comparing the pressure data with a reference value, after said first compressor is started and prior to starting said second compressor, when said two compressors are to be sequentially started at the intervals established by said second control means, means for providing a command for allowing start of operation of said second compressor to said second control means when the pressure data is determined by said comparing means to be equal to or higher than the reference value, and means for providing a command for inhibiting start of operation of said second compressor to said second control means when the pressure data is determined by said comparing means to be equal to or higher than the reference value, said third control means eliminating stopping of the two compressors and frequent ON and OFF operation of said second compressor when said air-conditioner apparatus is overloaded and said high-pressure-side pressure is extraordinarily increased.