LATEST!! HVAC: EPA 608 Certification Study Guide |Question and Answer| 100% Correct

LATEST!! HVAC: EPA 608 Certification Study Guide |Question and Answer| 100% Correct 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 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 Refrigeration Process *Ans* transfer of heat from one place to another Evaporator *Ans* 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 *Ans* Takes low pressure, low temp vapor and changes it to a high-temp, high-pressure, superheated vapor and delivers it to the condenser Condenser *Ans* Rejects heat from system and changes refrigerant from high-temp, high-pressure vapor into high-pressure, high-temp liquid Metering Device *Ans* reduces pressure of refrigerant and changes the high-pressure, high-temp liquid into low pressure, low temp liquid. Compound Gauge *Ans* Typically blue and measures low pressure (psig) and vacuum (inHg). High Pressure Gauge *Ans* Red and measures high side (discharge) pressure. 0 to 500 psi What does a compressor compress? *Ans* Vapor