Which statement about refrigerant oil replacement due to moisture is true?

Which statement about refrigerant oil replacement due to moisture is true?

• A. System saturated with moisture indicates oil replacement is necessary
• B. Oil replacement is unnecessary even if moisture is present
• C. Oil replacement is required only if the system has never been opened
• D. Oil replacement is never necessary due to atmospheric exposure

Answer: (A)

Moisture in refrigerant oil is harmful for the system and cannot be trusted to stay out or be fully removed by simple recovery acts. Water in the oil degrades lubrication, promotes varnish and sludge formation, and, under operating conditions, can react with refrigerants to form acids that corrode components and wear bearings. In many refrigerants, especially those using hygroscopic oils, any water present is difficult to purge once the system is closed, so contaminated oil will continue to cause problems unless it’s replaced. When the oil is saturated with moisture, replacing it with clean oil—and also refreshing the filter-drier and evacuating the system—is the reliable way to restore proper lubrication and prevent acid formation and corrosion. This is true even if the system hasn’t been opened recently, since moisture can be present from manufacturing, storage, or service.

Moisture in refrigerant oil is harmful for the system and cannot be trusted to stay out or be fully removed by simple recovery acts. Water in the oil degrades lubrication, promotes varnish and sludge formation, and, under operating conditions, can react with refrigerants to form acids that corrode components and wear bearings. In many refrigerants, especially those using hygroscopic oils, any water present is difficult to purge once the system is closed, so contaminated oil will continue to cause problems unless it’s replaced. When the oil is saturated with moisture, replacing it with clean oil—and also refreshing the filter-drier and evacuating the system—is the reliable way to restore proper lubrication and prevent acid formation and corrosion. This is true even if the system hasn’t been opened recently, since moisture can be present from manufacturing, storage, or service.