PURPOSE: To prevent frost from being deposited on an outdoor heat exchanger by installing a control valve.
CONSTITUTION: A capacity variable type compressor 1, a fourway valve 2, a room heat exchanger 3, a first expansion valve 4, a gas-liquid separator 5, a second expansion valve 6 and an outdoor heat exchanger 7 are connected to each other in the shape of a ring one after another, thereby constituting a main circuit to which an injection circuit is installed where the injection circuit is connected to a twoway valve 9 which is installed on the middle way of a piping to the suction of the capacity variable type compressor 1 from the gas outlet side of the gas-liquid separator 5 and the outlet of the outdoor heat exchanger 7 where the twoway valve 9 is designed to open under such a condition that a frost may be produced.
FUJITAKA AKIRA
SAWAI KIYOSHI
WATANABE YUKIO
