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

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

Mechanical shaft seals rely on optical flatness between lapped mating rings to prevent refrigerant leaks. Microscopic dirt particles trapped between these polished surfaces create gaps, destroying the seal face and causing immediate system leakage.