EPA 608 EXAM PREP SOLVED QUESTIONS
ACCURATE ANSWERS PREMIUM REVIEW
◉ 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
◉ 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?
ACCURATE ANSWERS PREMIUM REVIEW
◉ 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
◉ 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?
