HVAC: EPA 608 Certification Exam Questions and Answers, Latest Updated 2024/2025 (GRADED)

Are there drop-in replacements for R-12 systems? Why or why not? CORRECT ANSWERNo 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 ANSWEREster based oils and they do not mix with other oils What type of lubricant is used with HCFCs? CORRECT ANSWERAlkylbenzene lubricant What is difference b/w ternary blend a azeotropic blend? CORRECT ANSWERTernary blends are threepart 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 ANSWERIt absorbs (takes on) moisture What is temperature glide and what type of blend won't have it? CORRECT ANSWERTemp. blend is the difference between the dew point and the bubble point Dew Point CORRECT ANSWEROccurs when saturation temp in evaporator causes refrigerant to change from liquid to vapor Bubble Point CORRECT ANSWEROccurs 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 ANSWERNo because different refrigerants in blend have different vapor pressures, causing them to leak at uneven rates HVAC: EPA 608 Certification Exam Questions and Answers Latest Updated 2024/2025 (GRADED) Refrigeration Process CORRECT ANSWERtransfer of heat from one place to another Evaporator CORRECT ANSWERAbsorbs 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 ANSWERTakes low pressure, low temp vapor and changes it to a high-temp, highpressure, superheated vapor and delivers it to the condenser Condenser CORRECT ANSWERRejects heat from system and changes refrigerant from high-temp, highpressure vapor into high-pressure, high-temp liquid Metering Device CORRECT ANSWERreduces pressure of refrigerant and changes the high-pressure, hightemp liquid into low pressure, low temp liquid. Compound Gauge CORRECT ANSWERTypically blue and measures low pressure (psig) and vacuum (inHg). High Pressure Gauge CORRECT ANSWERRed and measures high side (discharge) pressure. 0 to 500 psi What does a compressor compress? CORRECT ANSWERVapor Why will refrigerant migrate to the crankcase in a compressor? CORRECT ANSWERBecause of the vapor pressure difference between refrigerant and oil What color is the high pressure gauge? CORRECT ANSWERRed What color is the low pressure gauge? CORRECT ANSWERBlue What needs to happen if oil has been contaminated by burnout? CORRECT ANSWERTriple evacuate system, install permanent filter-drier, conduct deep vacuum before recharging What are three Rs of refrigeration? CORRECT ANSWERRecover, recycle, reclaim Recover CORRECT ANSWERto remove any refrigerant in any condition from system and store in external container without necessarily testing or processing in any way Recycle CORRECT ANSWERTo clean refrigerant for immediate reuse by separating oil from refrigerant and removing moisture and acidity from refrigerant by use of products like filter driers Reclaim CORRECT ANSWERTo process refrigerant to level of new product specifications as determines by chemical analysis What standards must refrigerant recovery equipment meet and what components must all Type I and Type II refrigerant systems have? CORRECT ANSWEREPA-approved equipment testing organization. Service aperture or process stub System-Dependent Devices CORRECT ANSWERCapture refrigerant with assistance of compressor and/or pressure of refrigerant in appliances from which refrigerant is being recovered Self-contained Devices CORRECT ANSWERHave independent means to draw refrigerant out of appliances What is nitrogen and a filter-drier used for after recovery? CORRECT ANSWERUse nitrogen to flush debris out of system after recovering refrigerant. Filter-drier should be installed to trap any debris that may cause damage to new compressor What must be done before starting an evacuation? CORRECT ANSWERRecover all refrigerant and attain the mandated vacuum level ASHRAE Standard 15-1994 CORRECT ANSWERRequires refrigerant sensor that will sound alarm and automatically start ventilation system in occupied equipment rooms where refrigerant from leak will concentrate How often should refillable cylinders be hydrostatically tested? CORRECT ANSWER5 years What are the three ways you can control fill level of refillable cylinder? CORRECT ANSWERMechanical floats, electronic floats, or weight What is the EPA definition of a small appliance? CORRECT ANSWEROne that is manufactured, charged, and hermetically sealed in factory and contains five lbs. or less of refrigerant What standards must recovery equipment manufactured before Nov. 15th, 1993 meet? CORRECT ANSWERCapable of recovering 80% of refrigerant whether or not compressor is operating or achieve a 4-inch vacuum under conditions of ARI 740 What standards must recovery equipment manufactured AFTER Nov. 15th, 1993 meet? CORRECT ANSWERCapable of recovering 80% of refrigerant without compressor operating or achieve 4-inch vacuum under conditions of ARI 740; be capable of recovering 90% of refrigerant with compressor operating or achieve 4-inch vacuum under conditions of ARI 740; and must be approved by EPA approved third-party laboratory Low-loss Fittings CORRECT ANSWERCan be manually or automatically closed when disconnecting hoses in order to prevent refrigerant loss Service Aperture CORRECT ANSWERTypically straight piece of tubing that is entered with piercing access valve Find the pressure for R-12 at 80 degrees F. CORRECT ANSWER84.4 psi Find pressure for R-22 at 70 degree F. CORRECT ANSWER121.4 psi R-134A at 90 degree F CORRECT ANSWER104.3 psi