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HVAC-EPA-608-Certification Study Guide | Questions and Answers.

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HVAC: EPA 608 Certification Study Guide Questions and Answers, Graded A+ Are there drop-in replacements for R-12 systems? Why or why not? ✔✔ No because the new refrigerants are incompatible wit... h 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? ✔✔ Ester based oils and they do not mix with other oils What type of lubricant is used with HCFCs? ✔✔ Alkylbenzene lubricant What is difference b/w ternary blend a azeotropic blend? ✔✔ 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? ✔✔ It absorbs (takes on) moisture What is temperature glide and what type of blend won't have it? ✔✔ Temp. blend is the difference between the dew point and the bubble point Dew Point ✔✔ Occurs when saturation temp in evaporator causes refrigerant to change from liquid to vapor Bubble Point ✔✔ 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? ✔✔ No because different refrigerants in blend have different vapor pressures, causing them to leak at uneven rates Refrigeration Process ✔✔ transfer of heat from one place to another Evaporator ✔✔ 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 ✔✔ Takes low pressure, low temp vapor and changes it to a high-temp, high-pressure, superheated vapor and delivers it to the condenser Condenser ✔✔ Rejects heat from system and changes refrigerant from high-temp, high-pressure vapor into high-pressure, high-temp liquid Metering Device ✔✔ reduces pressure of refrigerant and changes the high-pressure, high-temp liquid into low pressure, low temp liquid. Compound Gauge ✔✔ Typically blue and measures low pressure (psig) and vacuum (inHg). High Pressure Gauge ✔✔ Red and measures high side (discharge) pressure. 0 to 500 psi What does a compressor compress? ✔✔ Vapor Why will refrigerant migrate to the crankcase in a compressor? ✔✔ Because of the vapor pressure difference between refrigerant and oil What color is the high pressure gauge? ✔✔ Red What color is the low pressure gauge? ✔✔ Blue What needs to happen if oil has been contaminated by burnout? ✔✔ Triple evacuate system, install permanent filter-drier, conduct deep vacuum before recharging What are three Rs of refrigeration? ✔✔ Recover, recycle, reclaim Recover ✔✔ to remove any refrigerant in any condition from system and store in external container without necessarily testing or processing in any way [Show More]

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