HVAC: EPA 608 Certification Study Guide Exam Questions And Answers

HVAC: EPA 608 Certification Study Guide Exam Questions And Answers Are there drop-in replacements for R-12 systems? Why or why not? - ANS 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? - ANS Ester based oils and they do not mix with other oils What type of lubricant is used with HCFCs? - ANS Alkylbenzene lubricant What is the difference b/w ternary blend a azeotropic blend? - ANS 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? - ANS It absorbs (takes on) moisture What is temperature glide and what type of blend won't have it? - ANS Temp. blend is the difference between the dew point and the bubble point Dew Point - ANS Occurs when saturation temp in evaporator causes refrigerant to change from liquid to vapor Bubble Point - ANS Occurs when saturation temp in condenser changes refrigerant from vapor to liquid Will the gases in a ternary blend leak at the same rate? Why or why not? - ANS No because different refrigerants in blend have different vapor pressures, causing them to leak at uneven rates