Three-pipe water source multi-split air conditioner and control method thereof

The invention discloses a three-pipe water source multi-split air conditioner and a control method thereof, and relates to the technical field of water source multi-split air conditioners. The protection shutdown problems of a compressor due to maximum heating of indoor units in the prior art can be reduced. The control method of the three-pipe water source multi-split air conditioner comprising an outdoor unit and a plurality of indoor units comprises the following steps of acquiring the suction pressure of the compressor in the outdoor unit; controlling a fist control valve unit to switch tothe second opening-closing state from the first open-closing state under the first conditions, and turning on a throttle device in a first indoor unit; the first conditions comprise a plurality of indoor units comprising at least one first indoor unit and at least one second indoor unit, and the indoor units connected to the first control valve unit are off at present; and the second opening-closing state of the first co