Which statement best describes hydrolysis in refrigerants?

• A. It is when refrigerant oil breaks down in the presence of water
• B. It is when refrigerant is recycled
• C. It is unrelated to refrigerants
• D. It is the same as oxidation

Answer: (A)

Hydrolysis is a chemical reaction where water causes a compound to break down. In refrigerant systems, moisture can react with refrigerant oil (especially ester-based POE oils used with many modern refrigerants) and, with heat, form acidic byproducts such as hydrofluoric and hydrochloric acids. These acids are corrosive to copper and other metals and can damage lubricants and seals, leading to system problems. The statement that refrigerant oil breaks down in the presence of water directly captures this water-driven decomposition process, which is what hydrolysis describes. The other ideas—recycling refrigerant, being unrelated to refrigerants, or equating hydrolysis with oxidation—do not describe this water-involved breakdown.