HVAC: EPA 608 Certification Study Guide

HVAC: EPA 608 Certification Study Guide 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 Compressor - correct answer-Takes low pressure, low temp vapor and changes it to a high-temp, high pressure, superheated vapor and delivers it to the conden