Insufficient refrigerant detection method for air-conditioner

PURPOSE: To securely detect lack of the encapsulated amount of a refrigerant without permitting mistaken operation even under any operation conditions, and issuing alarming and interrupting operation, and hence previously preventing a burning accident of a compressor by detecting a difference between refrigerant temperatures at an inlet and an outlet of a heat exchanger. CONSTITUTION: On a liquid refrigerant assembly piping 7 of a heat exchanger 6 that actuates as an evaporator upon cooling operation and as a condenser upon heating operation there is provided a thermistor 9, and on a gas refrigerant assembly piping 8 provided a thermistor 10, and further inside an air suction inlet there is provided a thermistor. When a temperature difference between an inlet refrigerant and an outlet refrigerant of the heat exchanger 6 becomes larger than a set value, when a temperature difference of the outlet refrigerant and heat exchanger suction air at the air suction inlet 4 is smaller than a predetermined value, and when a temperature difference between a temperature difference between the suction air and blowoff air is smaller than a set value, an alarming signal is issued from a controller 12 to light an alarming lamp or interrupt the operation. Hereby, a burning accident of a compressor 13 is previously prevented. COPYRIGHT: (C)1989,JPO