HVAC: EPA 608 Certification Study Guide Questions and
Answers | Latest Version | 2024/2025 | Rated A+
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 .singl
e .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 .u
neven .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. .Up
on .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 .nec
essarily .testing .or .processing .in .any .way
Answers | Latest Version | 2024/2025 | Rated A+
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 .singl
e .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 .u
neven .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. .Up
on .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 .nec
essarily .testing .or .processing .in .any .way
