The invention relates to an air conditioner using a combustible
refrigerant and a control method thereof. The air conditioner comprises a
refrigeration /
heat pump air conditioner
system which consists of a compressor, a four-way valve, an indoor
heat exchanger, a
throttle mechanism, and an outdoor
heat exchanger, wherein two ends of the indoor
heat exchanger are provided with an air conditioner connecting
pipe pneumatic valve and an air conditioner connecting
pipe hydraulic valve respectively; a
refrigerant working medium concentration sensor is arranged indoors; a drain
pipe branch and an automatic drain valve of the drain pipe
branch are arranged on the connecting pipes of the outdoor heat exchanger; the
refrigerant working medium concentration sensor is arranged beside the indoor heat exchanger; and the drain pipe
branch and the automatic drain valve of the drain pipe branch are arranged on the pipes between the
throttle mechanism and the outdoor heat exchanger. The air conditioner using the combustible refrigerant is provided with the refrigerant working medium concentration sensor, the drain pipe branch, and the automatic drain valve of the drain pipe branch, and when the combustible refrigerant working medium is detected to be leaked, an outdoor
machine part exhausts the refrigerant to the large outdoor space to reduce the indoor leakage quantity, so personal injury and property loss generated when the indoor combustible working medium concentration reaches the
combustion limit are avoided.