Air conditioning system

An air conditioning system comprising:

• an outdoor unit that comprises a first refrigerant circuit comprising:
• a compressor;
• and
• a first heat exchanger;
• an indoor unit in a first space and that comprises a second refrigerant circuit comprising a second heat exchanger;
• a liquid side pipe and a gas side pipe each connecting the first refrigerant circuit to the second refrigerant circuit;
• an outdoor air treatment unit comprising:
• a first auxiliary refrigerant circuit comprising a first auxiliary heat exchanger connected to:
• a first branching pipe branching from the liquid side pipe, and
• a second branching pipe branching from the gas side pipe;
• and
• a supply fan that supplies outdoor air having passed through the first auxiliary heat exchanger to the first space;
• a switching valve on the second branching pipe configured to be switched according to cooling and heating operations of the air conditioning system;
• a first shutoff valve on the first branching pipe;
• a second shutoff valve on the second branching pipe between the first auxiliary heat exchanger and the switching valve;
• and
• a motor valve on the first branching pipe configured to control quantity of refrigerant passing through the first auxiliary heat exchanger, wherein
• the first shutoff valve and the second shutoff valve each shut off a flow of refrigerant between the first refrigerant circuit and the first auxiliary refrigerant circuit.