Refrigerant Pressure Sensor / Switch: Description and Operation

TRIPLE (DUAL) PRESSURE SWITCH
The triple (dual) pressure switch is a combination of the low pressure switch (for checking the quantity of refrigerant), middle pressure switch (for cooling fans run) and the high pressure switch (for prevention of A/C ON. line burst). It is installed in the discharge pipe, and, when the pressure becomes approximately 2 kg/sq.cm G (200 kPa, 29 psi) or lower, the compressor stops, thus preventing the compressor from being damaged by sticking. When the pressure reaches 18 kg/sq.cm G (1,800 kPa, 261 psi) or higher, the cooling fans run high speed from low speed, thus preventing the power consumption of cooling fans from being discharged. When the pressure reaches 32 kg/sq.cm(2) G (3,214 kPa, 470 psi) or higher, the compressor stops, thus preventing A/C ON. line burst. There is generally no necessity for inspection; if, however, an unusual condition, such as non-operation of the compressor is encountered, check by following the procedures under Testing.