HVAC: EPA 608 Certification Study
Guide 100% Verified.
Are there drop-in replacements for R-12 systems? Why or why not? - 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? - 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? - answer✔✔Red
What color is the low pressure gauge? - answer✔✔Blue
What needs to happen if oil has been contaminated by burnout? - answer✔✔Triple evacuate
system, install permanent filter-drier, conduct deep vacuum before recharging
What are three Rs of refrigeration? - answer✔✔Recover, recycle, reclaim
Recover - answer✔✔to remove any refrigerant in any condition from system and store in
external container without necessarily testing or processing in any way
Recycle - answer✔✔To 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 - answer✔✔To 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? - answer✔✔EPA-approved equipment testing
organization. Service aperture or process stub
System-Dependent Devices - answer✔✔Capture refrigerant with assistance of compressor
and/or pressure of refrigerant in appliances from which refrigerant is being recovered
Self-contained Devices - answer✔✔Have independent means to draw refrigerant out of
appliances
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