EPA 608 VIEW AHEAD EXAM QUESTIONS FULL SOLUTION GUIDE
Question:
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
Question:
What type of lubricant is used with HCFCs?
Answer:
Alkylbenzene lubricant
Question:
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.
Question:
What is the trait of a hygroscopic lubricant?
Answer:
It absorbs (takes on) moisture
Question:
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
Question:
Dew Point
Answer:
Occurs when saturation temp in evaporator causes refrigerant to change from liquid to vapor
Question:
Bubble Point
Answer:
Occurs when saturation temp in condenser changes refrigerant from vapor to liquid
Question:
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
Question:
Refrigeration Process
Answer:
transfer of heat from one place to another
Question:
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
Question:
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
Question:
Condenser
Answer:
Rejects heat from system and changes refrigerant from high-temp, high-pressure vapor into
high-pressure, high-temp liquid
Question:
Metering Device
Answer:
reduces pressure of refrigerant and changes the high-pressure, high-temp liquid into low pressure,
low temp liquid.
Question:
Compound Gauge
Answer:
Typically blue and measures low pressure (psig) and vacuum (inHg).
Question:
High Pressure Gauge
Question:
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
Question:
What type of lubricant is used with HCFCs?
Answer:
Alkylbenzene lubricant
Question:
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.
Question:
What is the trait of a hygroscopic lubricant?
Answer:
It absorbs (takes on) moisture
Question:
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
Question:
Dew Point
Answer:
Occurs when saturation temp in evaporator causes refrigerant to change from liquid to vapor
Question:
Bubble Point
Answer:
Occurs when saturation temp in condenser changes refrigerant from vapor to liquid
Question:
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
Question:
Refrigeration Process
Answer:
transfer of heat from one place to another
Question:
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
Question:
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
Question:
Condenser
Answer:
Rejects heat from system and changes refrigerant from high-temp, high-pressure vapor into
high-pressure, high-temp liquid
Question:
Metering Device
Answer:
reduces pressure of refrigerant and changes the high-pressure, high-temp liquid into low pressure,
low temp liquid.
Question:
Compound Gauge
Answer:
Typically blue and measures low pressure (psig) and vacuum (inHg).
Question:
High Pressure Gauge
