Most welded hermetic compressor have no means of determining the oil. This type of compressor is primarily designed for installation in factory designed. assembled, and charged system where the systems the oil charge can be accurately measured into the system at the time of original assembly. In case of leak ,if the amount of oil lost is small and can be reasonably calculated, this amount should be added to compressor. If however, there is major loss of oil, the service technician must remove the compressor, drain the oil, and add the correct measured charge before replacing the compressor.
semihermatic and open type compressor are normally equipped with crankcase sight glasses, the oil level should be maintained at or slightly above the center of the sight-glass while operating. An abnormally low oil level may result in a loss of lubrication, while an excessively high oil circulation. The oil level may very considerably on initial start-up if liquid refrigerant is present in crankcase, and the oil level should be checked with the compressor running after having reached established condition.
