When installing a mechanical shaft seal on a refrigeration compressor, extreme care must be taken to prevent what from happening?

Correct Answer: Option D — dirt and foreign particles from coming in contact with the highly polished sealing surfaces

Mechanical shaft seals rely on optically flat, lapped carbon and ceramic faces to maintain hermetic integrity. Introducing microscopic dirt, grit, or foreign particles destroys this delicate sealing interface, resulting in immediate refrigerant and lubricating oil leakage.