EPA 608 Certification Study Guide
HVAC Questions and Answers 100%
A+ Graded Excel!!!
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.
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
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
What color is the low pressure gauge? - CORRECT ANSWER-Blue
What needs to happen if oil has been contaminated by burnout? - CORRECT ANSWER-
Triple evacuate system, install permanent filter-drier, conduct deep vacuum before
recharging
What are three Rs of refrigeration? - CORRECT ANSWER-Recover, recycle, reclaim
Recover - CORRECT ANSWER-to remove any refrigerant in any condition from system
and store in external container without necessarily testing or processing in any way
HVAC Questions and Answers 100%
A+ Graded Excel!!!
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.
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
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
What color is the low pressure gauge? - CORRECT ANSWER-Blue
What needs to happen if oil has been contaminated by burnout? - CORRECT ANSWER-
Triple evacuate system, install permanent filter-drier, conduct deep vacuum before
recharging
What are three Rs of refrigeration? - CORRECT ANSWER-Recover, recycle, reclaim
Recover - CORRECT ANSWER-to remove any refrigerant in any condition from system
and store in external container without necessarily testing or processing in any way
