HVAC: EPA 608
HVAC: EPA 608 CERTIFICATION STUDY GUIDE
EXAM QUESTIONS AND ANSWERS
Are there drop-in replacements for R-12 systems? Why or why not? -
correct 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? - correct
answer Ester based oils and they do not mix with other oils
What type of lubricant is used with HCFCs? - correct answer Alkylbenzene
lubricant
What is difference b/w ternary blend a azeotropic blend? - correct answer
Ternary blends are three-part mixtures whereas azeotropic blends are
blends of two or more compounds that act like a single compound.
,HVAC: EPA 608
What is the trait of a hygroscopic lubricant? - correct answer It absorbs
(takes on) moisture
What is temperature glide and what type of blend won't have it? - correct
answer Temp. blend is the difference between the dew point and the
bubble point
Dew Point - correct answer Occurs when saturation temp in evaporator
causes refrigerant to change from liquid to vapor
Bubble Point - correct 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? - correct answer No because different refrigerants in blend have
different vapor pressures, causing them to leak at uneven rates
Refrigeration Process - correct answer transfer of heat from one place to
another
Evaporator - correct 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
, HVAC: EPA 608
Compressor - correct 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 - correct answer Rejects heat from system and changes
refrigerant from high-temp, high-pressure vapor into high-pressure,
high-temp liquid
Metering Device - correct answer reduces pressure of refrigerant and
changes the high-pressure, high-temp liquid into low pressure, low
temp liquid.
Compound Gauge - correct answer Typically blue and measures low
pressure (psig) and vacuum (inHg).
High Pressure Gauge - correct answer Red and measures high side
(discharge) pressure. 0 to 500 psi
What does a compressor compress? - correct answer Vapor
Why will refrigerant migrate to the crankcase in a compressor? - correct
answer Because of the vapor pressure difference between refrigerant
and oil
What color is the high pressure gauge? - correct answer Red
HVAC: EPA 608 CERTIFICATION STUDY GUIDE
EXAM QUESTIONS AND ANSWERS
Are there drop-in replacements for R-12 systems? Why or why not? -
correct 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? - correct
answer Ester based oils and they do not mix with other oils
What type of lubricant is used with HCFCs? - correct answer Alkylbenzene
lubricant
What is difference b/w ternary blend a azeotropic blend? - correct answer
Ternary blends are three-part mixtures whereas azeotropic blends are
blends of two or more compounds that act like a single compound.
,HVAC: EPA 608
What is the trait of a hygroscopic lubricant? - correct answer It absorbs
(takes on) moisture
What is temperature glide and what type of blend won't have it? - correct
answer Temp. blend is the difference between the dew point and the
bubble point
Dew Point - correct answer Occurs when saturation temp in evaporator
causes refrigerant to change from liquid to vapor
Bubble Point - correct 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? - correct answer No because different refrigerants in blend have
different vapor pressures, causing them to leak at uneven rates
Refrigeration Process - correct answer transfer of heat from one place to
another
Evaporator - correct 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
, HVAC: EPA 608
Compressor - correct 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 - correct answer Rejects heat from system and changes
refrigerant from high-temp, high-pressure vapor into high-pressure,
high-temp liquid
Metering Device - correct answer reduces pressure of refrigerant and
changes the high-pressure, high-temp liquid into low pressure, low
temp liquid.
Compound Gauge - correct answer Typically blue and measures low
pressure (psig) and vacuum (inHg).
High Pressure Gauge - correct answer Red and measures high side
(discharge) pressure. 0 to 500 psi
What does a compressor compress? - correct answer Vapor
Why will refrigerant migrate to the crankcase in a compressor? - correct
answer Because of the vapor pressure difference between refrigerant
and oil
What color is the high pressure gauge? - correct answer Red
