Bubbles in the receiver dryer

[yebo]

bubbles in the refirgerant sight glass is normal only...
1. when the ac compressor had just been turned on (ac clutch is engaged) as the refrigerant has not yet been fully liquified in the high side (or condenser side) of the refrigerant system. when the pressure in the high side has reached its design pressure then there should be no more bubbles seen in the sight glass.
2. when the ac compressor had just been turned off (ac clutch is off) because the remaining liquid refrigerant vaporizes as the pressure between the high side (condenser) and low side (evaporator) equalizes.

when the ac compressor* has been running for a while there should be no more bubbles in the sight glass. bubbles in the sight glass is a sign of undercharge.

*compressor ha, hindi yung ac lang kasi pwede naka-on ang ac pero off ang clutch ng compressor.