Air conditioner and installing method of the air conditioner

An air conditioner, comprising:

• a compressor, an outdoor heat exchanger, an expansion valve and an indoor heat exchanger that are configured to be connected to one another through a liquid-side connection pipe and a gas-side connection pipe to form a refrigerant circuit for operation, wherein an outdoor unit includes the compressor, the outdoor heat exchanger and the expansion valve, with refrigerant flowing in operation from the compressor to the outdoor heat exchanger to the expansion valve, an indoor unit includes the indoor heat exchanger, and the outdoor unit and the indoor unit are configured to be connected to each other through the liquid-side connection pipe and the gas-side connection pipe to form the refrigerant circuit for operation;
• an outdoor liquid-side connection valve provided in the outdoor unit and directly connected to the liquid-side connection pipe;
• an outdoor gas-side connection valve provided in the outdoor unit and directly connected to the gas-side connection pipe;
• a refrigerant charge port provided in the outdoor liquid-side connection valve or the outdoor gas-side connection valve;
• a liquid-side valve provided upstream from the outdoor liquid-side connection valve and downstream from the expansion valve;
• a gas-side valve provided downstream from the outdoor gas-side connection valve and upstream from the compressor;
• a pressure detector provided downstream from the liquid-side valve and upstream from the outdoor liquid-side valve, to detect a degree of vacuum of:
• a first pipe disposed downstream from the liquid-side valve and upstream from the outdoor liquid-side connection valve,
• the liquid-side connection pipe,
• a second pipe disposed downstream from the indoor liquid-side valve and upstream from the indoor-side heat exchanger,
• the indoor-side heat exchanger,
• a third pipe disposed downstream from the indoor-side heat exchanger and upstream from the indoor gas-side connection valve,
• the gas-side connection pipe, and
• a fourth pipe disposed downstream from the outdoor gas-side connection valve and upstream from the gas-side valve;
• and
• a control unit that is configured to close the refrigerant charge port and then open the liquid-side valve and the gas-side valve when the pressure detector detects a predetermined degree of vacuum when in a state where the liquid-side valve and the gas-side valve are closed, and a refrigerant is charged into:
• a fifth pipe disposed upstream from the liquid-side valve and downstream from the expansion valve,
• the expansion valve,
• a sixth pipe disposed upstream from the expansion valve and downstream from the outdoor-side heat exchanger,
• the outdoor-side heat exchanger,
• a seventh pipe disposed upstream from the outdoor-side heat exchanger and downstream from the compressor,
• the compressor, and
• an eighth pipe disposed upstream from the compressor and downstream from the gas-side valve, which is closed by the compressor and the gas-side valve.