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HVAC: EPA 608 CERTIFICATION STUDY GUIDE
QUESTIONS NEWEST 2025 ACTUAL EXAM 100
QUESTIONS AND CORRECT DETAILED ANSWERS /
ALREADY GRADED A+
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
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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
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).
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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
What are three Rs of refrigeration? - (answer)Recover, recycle, reclaim
Recover - (answer)to remove any refrigerant in any condition from system and
store in external container without necessarily testing or processing in any way
HVAC: EPA 608 CERTIFICATION STUDY GUIDE
QUESTIONS NEWEST 2025 ACTUAL EXAM 100
QUESTIONS AND CORRECT DETAILED ANSWERS /
ALREADY GRADED A+
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
, 2
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
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).
, 3
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
What are three Rs of refrigeration? - (answer)Recover, recycle, reclaim
Recover - (answer)to remove any refrigerant in any condition from system and
store in external container without necessarily testing or processing in any way
