Dear fellows:

In the last couple of months I have had to replace a few stuck hermetic piston-type compressors in remote condensing units. Autopsies performed on the dead compressors usually reveal lack-of-oil related problems. Besides the obvious need to find the main reason behind the oil return problem in each case, I´ve always asked myself if there is any reliable method to estimate the crankcase oil level in one of these hermetic compresors. I´ve seen some new Danfoss and Bristol made compressors equiped with oil sightglasses, but the majority of these compressors lack this feature.
Also, does any of you have a preferred method for obtaining an oil sample from the hermetic compressor´s crankcase for acidity testing ? I guess that some sort of sampling port would be useful not only for sampling but also for drainage purposes in case there is a need for an oil change.
Best regards.