HVAC: EPA 608 CERTIFICATION - REAL QUESTIONS + DETAILED
ANSWERS - LATEST VERSION - TOP RATED 2026
Are R-12 systems available as drop-in replacements? Why not? The oils and
lubricants used in R-12 systems are incompatible with the new refrigerants,
hence the ANSWER is no.
What kind of oil does R-134a use, and what kinds of oils will it mix with?
ANSWER : Ester-based oils don't combine with other types of oils.
With HCFCs, what kind of lubricant is used? ANSWER Lubricant made with
alkylbenzene
What distinguishes an azeotropic blend from a ternary blend? ANSWER
Azeotropic blends are combinations of two or more compounds that behave like
a single substance, while ternary blends are three-part mixes.
What characteristics distinguish a hygroscopic lubricant? - ANSWER It takes
on or absorbs moisture.
Which blends won't have temperature glide, and what does it mean? ANSWER
Temp. The difference between the dew point and the bubble point is called
blend.
Dew Point: ANSWER : When the evaporator reaches saturation temperature,
the refrigerant turns from liquid to vapor.
When the condenser's saturation temperature transforms refrigerant from vapor
to liquid, the bubble point occurs.
Will a ternary blend's gases leak at the same pace? Why not? ANSWER : No,
since the vapor pressures of the various refrigerants in the blend vary, resulting
in inconsistent rates of leakage.
The process of refrigeration involves moving heat from one location to another.
In order to cool the system, heat is absorbed from space by the evaporator.
When heat is absorbed, refrigerant boils. After departing, the refrigerant
, transformed into low-temperature, low-pressure vapor.
A compressor transforms low-pressure, low-temperature vapor into high-
temperature, high-pressure, superheated vapor, which is then sent to the
condenser.
The condenser rejects heat from the system and converts high-temperature,
high-pressure vaporized refrigerant into high-temperature, high-pressure liquid.
The ANSWER metering device lowers the refrigerant pressure and converts
the high-pressure, high-temperature liquid into a low-pressure, low-temperature
liquid.
Compound gauge: ANSWER : Usually blue, this device measures vacuum
(inHg) and low pressure (psig).
High side (discharge) pressure is measured by the ANSWER Red high
pressure gauge. Between 0 and 500 psi
What is compressed by a compressor? ANSWER Vapor
What causes refrigerant to move to a compressor's crankcase? Because oil and
refrigerant have different vapor pressures, the ANSWER
The high pressure gauge is what color? ANSWER Red
The low pressure gauge is what color? ANSWER Blue
What should be done if burnout has contaminated the oil? ANSWER Before
recharging, perform a deep vacuum, install a permanent filter-drier, and triple
evacuate the system.
What are refrigeration's three Rs? Recover, recycle, and reclaim
Recover: ANSWER to take any refrigerant out of the system in whatever
condition and put it in an external container without doing any testing or
processing.
Recycle- ANSWER To clean refrigerant for instant reuse, separate oil from
refrigerant, then utilize equipment like filter driers to remove moisture and
acidity.
Reclaim: ANSWER : Reclaim refrigerant by chemical analysis to meet new
ANSWERS - LATEST VERSION - TOP RATED 2026
Are R-12 systems available as drop-in replacements? Why not? The oils and
lubricants used in R-12 systems are incompatible with the new refrigerants,
hence the ANSWER is no.
What kind of oil does R-134a use, and what kinds of oils will it mix with?
ANSWER : Ester-based oils don't combine with other types of oils.
With HCFCs, what kind of lubricant is used? ANSWER Lubricant made with
alkylbenzene
What distinguishes an azeotropic blend from a ternary blend? ANSWER
Azeotropic blends are combinations of two or more compounds that behave like
a single substance, while ternary blends are three-part mixes.
What characteristics distinguish a hygroscopic lubricant? - ANSWER It takes
on or absorbs moisture.
Which blends won't have temperature glide, and what does it mean? ANSWER
Temp. The difference between the dew point and the bubble point is called
blend.
Dew Point: ANSWER : When the evaporator reaches saturation temperature,
the refrigerant turns from liquid to vapor.
When the condenser's saturation temperature transforms refrigerant from vapor
to liquid, the bubble point occurs.
Will a ternary blend's gases leak at the same pace? Why not? ANSWER : No,
since the vapor pressures of the various refrigerants in the blend vary, resulting
in inconsistent rates of leakage.
The process of refrigeration involves moving heat from one location to another.
In order to cool the system, heat is absorbed from space by the evaporator.
When heat is absorbed, refrigerant boils. After departing, the refrigerant
, transformed into low-temperature, low-pressure vapor.
A compressor transforms low-pressure, low-temperature vapor into high-
temperature, high-pressure, superheated vapor, which is then sent to the
condenser.
The condenser rejects heat from the system and converts high-temperature,
high-pressure vaporized refrigerant into high-temperature, high-pressure liquid.
The ANSWER metering device lowers the refrigerant pressure and converts
the high-pressure, high-temperature liquid into a low-pressure, low-temperature
liquid.
Compound gauge: ANSWER : Usually blue, this device measures vacuum
(inHg) and low pressure (psig).
High side (discharge) pressure is measured by the ANSWER Red high
pressure gauge. Between 0 and 500 psi
What is compressed by a compressor? ANSWER Vapor
What causes refrigerant to move to a compressor's crankcase? Because oil and
refrigerant have different vapor pressures, the ANSWER
The high pressure gauge is what color? ANSWER Red
The low pressure gauge is what color? ANSWER Blue
What should be done if burnout has contaminated the oil? ANSWER Before
recharging, perform a deep vacuum, install a permanent filter-drier, and triple
evacuate the system.
What are refrigeration's three Rs? Recover, recycle, and reclaim
Recover: ANSWER to take any refrigerant out of the system in whatever
condition and put it in an external container without doing any testing or
processing.
Recycle- ANSWER To clean refrigerant for instant reuse, separate oil from
refrigerant, then utilize equipment like filter driers to remove moisture and
acidity.
Reclaim: ANSWER : Reclaim refrigerant by chemical analysis to meet new
