Air conditioning and ventilating system

An air conditioning and ventilating system (S) comprising:

• an air conditioning device (A) including a heat exchanger (22) configured to generate conditioned air by heat exchange with a refrigerant, and configured to send the conditioned air to an air conditioned space (R);
• a ventilation device (30) configured to ventilate the air conditioned space (R);
• a refrigerant sensor (24) configured to detect concentration of the refrigerant in the air conditioned space (R);
• and
• a control unit (40) configured to control operations of the air conditioning device (A) and the ventilation device (30),
• wherein on determination that the refrigerant concentration acquired from the refrigerant sensor (24) exceeds a first predetermined value, the control unit (40) sets an operation of a compressor (13) of the air conditioning device (A) to a stop state and sets the ventilation device (30) to an operating state, and
• on determination that the refrigerant concentration that has exceeded the first predetermined value becomes equal to or less than the first predetermined value, the control unit (40) continues the stop state of the compressor (13) of the air conditioning device (A) and the operating state of the ventilation device (30) until predetermined timing to prevent an unevenness of the refrigerant concentration in the air conditioned space.