My R134A drier has a sight glass.... minsan may bubbles, minsan wala...

...pero di talaga dapat basis yung bubbles lang 'coz pwedeng overcharged na yung refrigerant, pero may bubbles pa rin... The pressure has to be checked on both high and low pressure sides talaga. Pwede kasing loose compression na yung compressor, or pwedeng yung expansion valve ay kailangan nang palitan...