HVAC: EPA 608 Certification Study Guide
Are there drop-in replacements for R-12 systems? Why or why not? - ANSNo 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? - ANSEster based oils and they
do not mix with other oils
What type of lubricant is used with HCFCs? - ANSAlkylbenzene lubricant
What is difference b/w ternary blend a azeotropic blend? - ANSTernary 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? - ANSIt absorbs (takes on) moisture
What is temperature glide and what type of blend won't have it? - ANSTemp. blend is the
difference between the dew point and the bubble point
Dew Point - ANSOccurs when saturation temp in evaporator causes refrigerant to change from
liquid to vapor
Bubble Point - ANSOccurs 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? - ANSNo because
different refrigerants in blend have different vapor pressures, causing them to leak at uneven
rates
Refrigeration Process - ANStransfer of heat from one place to another
Evaporator - ANSAbsorbs 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 - ANSTakes low pressure, low temp vapor and changes it to a high-temp,
high-pressure, superheated vapor and delivers it to the condenser
Condenser - ANSRejects heat from system and changes refrigerant from high-temp,
high-pressure vapor into high-pressure, high-temp liquid
Metering Device - ANSreduces pressure of refrigerant and changes the high-pressure,
high-temp liquid into low pressure, low temp liquid.
, Compound Gauge - ANSTypically blue and measures low pressure (psig) and vacuum (inHg).
High Pressure Gauge - ANSRed and measures high side (discharge) pressure. 0 to 500 psi
What does a compressor compress? - ANSVapor
Why will refrigerant migrate to the crankcase in a compressor? - ANSBecause of the vapor
pressure difference between refrigerant and oil
What color is the high pressure gauge? - ANSRed
What color is the low pressure gauge? - ANSBlue
What needs to happen if oil has been contaminated by burnout? - ANSTriple evacuate system,
install permanent filter-drier, conduct deep vacuum before recharging
What are three Rs of refrigeration? - ANSRecover, recycle, reclaim
Recover - ANSto remove any refrigerant in any condition from system and store in external
container without necessarily testing or processing in any way
Recycle - ANSTo clean refrigerant for immediate reuse by separating oil from refrigerant and
removing moisture and acidity from refrigerant by use of products like filter driers
Reclaim - ANSTo process refrigerant to level of new product specifications as determines by
chemical analysis
What standards must refrigerant recovery equipment meet and what components must all Type
I and Type II refrigerant systems have? - ANSEPA-approved equipment testing organization.
Service aperture or process stub
System-Dependent Devices - ANSCapture refrigerant with assistance of compressor and/or
pressure of refrigerant in appliances from which refrigerant is being recovered
Self-contained Devices - ANSHave independent means to draw refrigerant out of appliances
What is nitrogen and a filter-drier used for after recovery? - ANSUse nitrogen to flush debris out
of system after recovering refrigerant. Filter-drier should be installed to trap any debris that may
cause damage to new compressor
What must be done before starting an evacuation? - ANSRecover all refrigerant and attain the
mandated vacuum level
Are there drop-in replacements for R-12 systems? Why or why not? - ANSNo 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? - ANSEster based oils and they
do not mix with other oils
What type of lubricant is used with HCFCs? - ANSAlkylbenzene lubricant
What is difference b/w ternary blend a azeotropic blend? - ANSTernary 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? - ANSIt absorbs (takes on) moisture
What is temperature glide and what type of blend won't have it? - ANSTemp. blend is the
difference between the dew point and the bubble point
Dew Point - ANSOccurs when saturation temp in evaporator causes refrigerant to change from
liquid to vapor
Bubble Point - ANSOccurs 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? - ANSNo because
different refrigerants in blend have different vapor pressures, causing them to leak at uneven
rates
Refrigeration Process - ANStransfer of heat from one place to another
Evaporator - ANSAbsorbs 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 - ANSTakes low pressure, low temp vapor and changes it to a high-temp,
high-pressure, superheated vapor and delivers it to the condenser
Condenser - ANSRejects heat from system and changes refrigerant from high-temp,
high-pressure vapor into high-pressure, high-temp liquid
Metering Device - ANSreduces pressure of refrigerant and changes the high-pressure,
high-temp liquid into low pressure, low temp liquid.
, Compound Gauge - ANSTypically blue and measures low pressure (psig) and vacuum (inHg).
High Pressure Gauge - ANSRed and measures high side (discharge) pressure. 0 to 500 psi
What does a compressor compress? - ANSVapor
Why will refrigerant migrate to the crankcase in a compressor? - ANSBecause of the vapor
pressure difference between refrigerant and oil
What color is the high pressure gauge? - ANSRed
What color is the low pressure gauge? - ANSBlue
What needs to happen if oil has been contaminated by burnout? - ANSTriple evacuate system,
install permanent filter-drier, conduct deep vacuum before recharging
What are three Rs of refrigeration? - ANSRecover, recycle, reclaim
Recover - ANSto remove any refrigerant in any condition from system and store in external
container without necessarily testing or processing in any way
Recycle - ANSTo clean refrigerant for immediate reuse by separating oil from refrigerant and
removing moisture and acidity from refrigerant by use of products like filter driers
Reclaim - ANSTo process refrigerant to level of new product specifications as determines by
chemical analysis
What standards must refrigerant recovery equipment meet and what components must all Type
I and Type II refrigerant systems have? - ANSEPA-approved equipment testing organization.
Service aperture or process stub
System-Dependent Devices - ANSCapture refrigerant with assistance of compressor and/or
pressure of refrigerant in appliances from which refrigerant is being recovered
Self-contained Devices - ANSHave independent means to draw refrigerant out of appliances
What is nitrogen and a filter-drier used for after recovery? - ANSUse nitrogen to flush debris out
of system after recovering refrigerant. Filter-drier should be installed to trap any debris that may
cause damage to new compressor
What must be done before starting an evacuation? - ANSRecover all refrigerant and attain the
mandated vacuum level
