HVAC: EPA 608 Certification Study Guide Questions with correct answers

Are there drop-in replacements for R-12 systems? Why or why not? Correct Answer - No because the new refrigerants are incompatible with the oils and lubricants used in R-12 systems. What type of oil is used in R-134a and what oils will it mix with? Correct Answer - Ester based oils and they do not mix with other oils What type of lubricant is used with HCFCs? Correct Answer - Alkylbenzene lubricant What is difference b/w ternary blend a azeotropic blend? Correct Answer - Ternary blends are three-part mixtures whereas azeotropic blends are blends of two or more compounds that act like a single compound. What is the trait of a hygroscopic lubricant? Correct Answer - It absorbs (takes on) moisture What is temperature glide and what type of blend won't have it? Correct Answer - Temp. blend is the difference between the dew point and the bubble point Dew Point Correct Answer - Occurs when saturation temp in evaporator causes refrigerant to change from liquid to vapor Bubble Point Correct Answer - Occurs when saturation temp in condenser changes refrigerant from vapor to liquid