HVAC EPA 608 Certification Study Guide Questions with Correct Answers
2026/2027 | Comprehensive Exam Prep|EPA Section 608 Certification –
HVAC Technician Study Guide (2026/2027 A+ Edition)
Are there drop-in replacements for R-12 systems? Why or why not? - (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? - (ANSWER)Ester based oils and they do
not mix with other oils
What type of lubricant is used with HCFCs? - (ANSWER)Alkylbenzene lubricant
What is difference b/w ternary blend a azeotropic blend? - (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? - (ANSWER)It absorbs (takes on) moisture
What is temperature glide and what type of blend won't have it? - (ANSWER)Temp. blend is the
difference between the dew point and the bubble point
Dew Point - (ANSWER)Occurs when saturation temp in evaporator causes refrigerant to change from
liquid to vapor
Bubble Point - (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? - (ANSWER)No because
different refrigerants in blend have different vapor pressures, causing them to leak at uneven rates
Refrigeration Process - (ANSWER)transfer of heat from one place to another
, HVAC EPA 608 Certification Study Guide Questions with Correct Answers
2026/2027 | Comprehensive Exam Prep|EPA Section 608 Certification –
HVAC Technician Study Guide (2026/2027 A+ Edition)
Evaporator - (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 - (ANSWER)Takes low pressure, low temp vapor and changes it to a high-temp, high-
pressure, superheated vapor and delivers it to the condenser
Condenser - (ANSWER)Rejects heat from system and changes refrigerant from high-temp, high-pressure
vapor into high-pressure, high-temp liquid
Metering Device - (ANSWER)reduces pressure of refrigerant and changes the high-pressure, high-temp
liquid into low pressure, low temp liquid.
Compound Gauge - (ANSWER)Typically blue and measures low pressure (psig) and vacuum (inHg).
High Pressure Gauge - (ANSWER)Red and measures high side (discharge) pressure. 0 to 500 psi
What does a compressor compress? - (ANSWER)Vapor
Why will refrigerant migrate to the crankcase in a compressor? - (ANSWER)Because of the vapor
pressure difference between refrigerant and oil
What color is the high pressure gauge? - (ANSWER)Red
What color is the low pressure gauge? - (ANSWER)Blue
What needs to happen if oil has been contaminated by burnout? - (ANSWER)Triple evacuate system,
install permanent filter-drier, conduct deep vacuum before recharging
2026/2027 | Comprehensive Exam Prep|EPA Section 608 Certification –
HVAC Technician Study Guide (2026/2027 A+ Edition)
Are there drop-in replacements for R-12 systems? Why or why not? - (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? - (ANSWER)Ester based oils and they do
not mix with other oils
What type of lubricant is used with HCFCs? - (ANSWER)Alkylbenzene lubricant
What is difference b/w ternary blend a azeotropic blend? - (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? - (ANSWER)It absorbs (takes on) moisture
What is temperature glide and what type of blend won't have it? - (ANSWER)Temp. blend is the
difference between the dew point and the bubble point
Dew Point - (ANSWER)Occurs when saturation temp in evaporator causes refrigerant to change from
liquid to vapor
Bubble Point - (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? - (ANSWER)No because
different refrigerants in blend have different vapor pressures, causing them to leak at uneven rates
Refrigeration Process - (ANSWER)transfer of heat from one place to another
, HVAC EPA 608 Certification Study Guide Questions with Correct Answers
2026/2027 | Comprehensive Exam Prep|EPA Section 608 Certification –
HVAC Technician Study Guide (2026/2027 A+ Edition)
Evaporator - (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 - (ANSWER)Takes low pressure, low temp vapor and changes it to a high-temp, high-
pressure, superheated vapor and delivers it to the condenser
Condenser - (ANSWER)Rejects heat from system and changes refrigerant from high-temp, high-pressure
vapor into high-pressure, high-temp liquid
Metering Device - (ANSWER)reduces pressure of refrigerant and changes the high-pressure, high-temp
liquid into low pressure, low temp liquid.
Compound Gauge - (ANSWER)Typically blue and measures low pressure (psig) and vacuum (inHg).
High Pressure Gauge - (ANSWER)Red and measures high side (discharge) pressure. 0 to 500 psi
What does a compressor compress? - (ANSWER)Vapor
Why will refrigerant migrate to the crankcase in a compressor? - (ANSWER)Because of the vapor
pressure difference between refrigerant and oil
What color is the high pressure gauge? - (ANSWER)Red
What color is the low pressure gauge? - (ANSWER)Blue
What needs to happen if oil has been contaminated by burnout? - (ANSWER)Triple evacuate system,
install permanent filter-drier, conduct deep vacuum before recharging
