HVAC: EPA 608 Certification Study Guide 100 Questions with Correct Answers

HVAC: EPA 608 Certification Study Guide 100 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 Will the gases in a ternary blend leak at the same rate? Why or why not? - Correct Answer No because different refrigerants in blend have different vapor pressures, causing them to leak at uneven rates Refrigeration Process - Correct Answer transfer of heat from one place to another Evaporator - Correct Answer Absorbs heat into system from space to be cooled. Absorption of heat causes refrigerant to boil. Upon leaving, refrigerant changed to low pressure, low temperature vapor