Local 94 School - 475 terms to know for the RMO
written exam Questions And Revised Correct
Answers
How .do .automatic .expansion .valves .work? .- .(correct .answer) .-Evaporator .pressure
.closes .the .valve .and .spring .pressure .opens .the .valve.
When .will .a .faulty .check .valve .cause .the .most .damage? .- .(correct .answer) .-On
.startup.
What .will .happen .if .a .TEV'S .sensing .bulb .insulation .wears .off .of .the .suction .line .in
.an .85 .F .Degree .room? .- .(correct .answer) .-You .will .flood .the .evaporator.
What .can .a .clogged .pump .strainer .cause? .- .(correct .answer) .-A .reduction .or .loss .in
.water .flow .which .will .lead .to .high .condenser .head .pressure.
What .part .of .the .Refrigeration .system .is .the .solenoid .valve .part .of? .- .(correct .answer)
.-The .pump .down .cycle .(Thermostat .- .Solenoid .Valve .- .Low .Pressure .Controller).
What .is .the .proper .machine .start .up .procedure? .- .(correct .answer) .-Check .oil, .start
.chilled .water .pump, .start .condenser .water .pump, .start .tower .fans .and .start .up
.machine.
How .does .a .reciprocating .machine .cycle .compressors .on .and .off? .- .(correct .answer)
.-Through .the .use .of .the .low .pressure .control.
What .refrigerant .has .the .best .Refrigeration .effect .and .highest .latent .heat? .- .(correct
.answer) .-Ammonia .(R-717) ./ .ASHRE .Classification .is .B2.
What .is .the .leaving .water .temperature .of .an .induced .draft .cooling .tower .that .is
.operating .efficiently? .- .(correct .answer) .-At .some .temperature .between .the .dry .and
.wet .bulb .temperature.
,What .could .a .sudden .reduction .in .the .supply .flow .of .the .cooling .tower .water .result
.in? .- .(correct .answer) .-An .increase .in .head .pressure.
How .do .reciprocating .compressor .unloaders .operate? .- .(correct .answer) .-By .keeping
.the .compressor .suction .valves .open.
Which .side .of .the .compressor .is .R-22 .vapor .charged .into? .- .(correct .answer) .-The
.suction .side.
What .should .the .percentage .of .lubricant .circulated .through .a .well .designed .system
.be? .- .(correct .answer) .-Lubricant .should .not .exceed .10%.
What .is .oil .foaming .in .the .compressor .a .result .of? .- .(correct .answer) .-Liquid
.refrigerant .in .the .crankcase.
What .is .the .main .reason .for .installing .an .oil .separator .on .the .discharge .line? .-
.(correct .answer) .-To .return .oil .back .to .the .compressor .crank .case.
What .causes .the .foaming .of .oil .in .a .reciprocating .compressor .using .the .splash
.system .for .lubrication? .- .(correct .answer) .-A .rapid .decrease .in .pressure.
What .is .the .purpose .of .oil .in .a .refrigerant .compressor? .- .(correct .answer) .-It .reduces
.ware .and .friction.
What .is .a .filter .dryer .used .to .remove? .- .(correct .answer) .-Moisture, .particles .and
.contaminants.
Where .in .a .refrigeration .system .is .the .oil .separator .located? .- .(correct .answer) .-On
.the .discharge .line .as .far .from .the .compressor .as .possible.
If .a .motor .has .4 .belts .and .1 .of .the .4 .belts .are .worn, .how .many .belts .should .be
.replaced? .- .(correct .answer) .-All .of .the .belts .should .be .replaced.
Does .a .solenoid .valve .vary .or .control .the .flow .of .refrigerant? .- .(correct .answer) .-No.
What .accessory .meters .and .controls .the .flow .of .refrigerant .into .the .evaporator? .-
.(correct .answer) .-The .TEV .(Metering .Device).
What .will .occur .if .you .use .an .automatic .expansion .valve .with .a .variable .load? .-
.(correct .answer) .-You .will .starve .the .evaporator.
What .does .an .automatic .expansion .valve .do? .- .(correct .answer) .-It .maintains .a
.constant .evaporator .pressure.
What .could .cause .the .evaporator .to .not .respond .to .the .adjustments .of .the .TEV? .-
.(correct .answer) .-Oil .logged .on .the .low .side.
, What .can .non-condensible's .cause? .- .(correct .answer) .-High .head .pressure.
When .will .compressor .motor .horsepower .increase? .- .(correct .answer) .-It .will .increase
.as .the .head .pressure .increases.
When .will .compressor .motor .horsepower .decrease? .- .(correct .answer) .-As .the
.suction .pressure .increases.
When .using .a .brine .solution .in .a .system .what .can .be .used .to .prevent .rusting? .-
.(correct .answer) .-Di-Chromate .Tablets.
What .would .cause .a .Halide .torch .flame .to .turn .yellow? .- .(correct .answer) .-A .clogged
.sample .tube.
What .is .the .purpose .of .having .2 .compressors .in .a .cascade .system? .- .(correct
.answer) .-To .operate .and .very .low .temperatures .and .avoid .high .compression .ratio.
Why .is .a .pressure .relief .valve .better .than .a .fusible .plug? .- .(correct .answer) .-Because
.it .can .be .re-seated .and .is .cost .efficient.
What .could .cause .compressor .knocking? .- .(correct .answer) .-Liquid .refrigerant
.slugging .the .compressor.
What .would .occur .if .a .TEV'S .spring .were .to .break? .- .(correct .answer) .-It .would .flood
.the .evaporator .and .raise .the .suction .pressure .because .a .TEV .uses .spring .pressure
.as .its .closing .force. .Thus, .if .the .spring .does .not .close .the .TEV .refrigerant .will
.constantly .be .metered .into .the .evaporator.
What .is .the .purpose .of .the .TEV .equalizer .line? .- .(correct .answer) .-It .compensates .for
.the .pressure .drop .in .the .evaporator. .Simply .put, .it .equalizes .pressure .drop .lost
.across .the .evaporator.
What .should .be .done .when .installing .copper .pipe .and .a .90 .degree .elbow .is .needed?
.- .(correct .answer) .-You .should .BRAZE .in .a .FACTORY .MADE .90 .degree .elbow.
What .is .the .purpose .of .a .service .valve .stem .cap? .- .(correct .answer) .-It .protects .the
.valve .from .refrigerant .leakage.
What .advantage .do .semi .hermetic .compressor's .have .over .hermetic .compressor's? .-
.(correct .answer) .-Semi .hermetic .compressor's .can .be .serviced.
What .happens .when .using .portable .compressor .recovery .unit .to .remove .vapor? .-
.(correct .answer) .-The .vapor .density .is .decreased.
written exam Questions And Revised Correct
Answers
How .do .automatic .expansion .valves .work? .- .(correct .answer) .-Evaporator .pressure
.closes .the .valve .and .spring .pressure .opens .the .valve.
When .will .a .faulty .check .valve .cause .the .most .damage? .- .(correct .answer) .-On
.startup.
What .will .happen .if .a .TEV'S .sensing .bulb .insulation .wears .off .of .the .suction .line .in
.an .85 .F .Degree .room? .- .(correct .answer) .-You .will .flood .the .evaporator.
What .can .a .clogged .pump .strainer .cause? .- .(correct .answer) .-A .reduction .or .loss .in
.water .flow .which .will .lead .to .high .condenser .head .pressure.
What .part .of .the .Refrigeration .system .is .the .solenoid .valve .part .of? .- .(correct .answer)
.-The .pump .down .cycle .(Thermostat .- .Solenoid .Valve .- .Low .Pressure .Controller).
What .is .the .proper .machine .start .up .procedure? .- .(correct .answer) .-Check .oil, .start
.chilled .water .pump, .start .condenser .water .pump, .start .tower .fans .and .start .up
.machine.
How .does .a .reciprocating .machine .cycle .compressors .on .and .off? .- .(correct .answer)
.-Through .the .use .of .the .low .pressure .control.
What .refrigerant .has .the .best .Refrigeration .effect .and .highest .latent .heat? .- .(correct
.answer) .-Ammonia .(R-717) ./ .ASHRE .Classification .is .B2.
What .is .the .leaving .water .temperature .of .an .induced .draft .cooling .tower .that .is
.operating .efficiently? .- .(correct .answer) .-At .some .temperature .between .the .dry .and
.wet .bulb .temperature.
,What .could .a .sudden .reduction .in .the .supply .flow .of .the .cooling .tower .water .result
.in? .- .(correct .answer) .-An .increase .in .head .pressure.
How .do .reciprocating .compressor .unloaders .operate? .- .(correct .answer) .-By .keeping
.the .compressor .suction .valves .open.
Which .side .of .the .compressor .is .R-22 .vapor .charged .into? .- .(correct .answer) .-The
.suction .side.
What .should .the .percentage .of .lubricant .circulated .through .a .well .designed .system
.be? .- .(correct .answer) .-Lubricant .should .not .exceed .10%.
What .is .oil .foaming .in .the .compressor .a .result .of? .- .(correct .answer) .-Liquid
.refrigerant .in .the .crankcase.
What .is .the .main .reason .for .installing .an .oil .separator .on .the .discharge .line? .-
.(correct .answer) .-To .return .oil .back .to .the .compressor .crank .case.
What .causes .the .foaming .of .oil .in .a .reciprocating .compressor .using .the .splash
.system .for .lubrication? .- .(correct .answer) .-A .rapid .decrease .in .pressure.
What .is .the .purpose .of .oil .in .a .refrigerant .compressor? .- .(correct .answer) .-It .reduces
.ware .and .friction.
What .is .a .filter .dryer .used .to .remove? .- .(correct .answer) .-Moisture, .particles .and
.contaminants.
Where .in .a .refrigeration .system .is .the .oil .separator .located? .- .(correct .answer) .-On
.the .discharge .line .as .far .from .the .compressor .as .possible.
If .a .motor .has .4 .belts .and .1 .of .the .4 .belts .are .worn, .how .many .belts .should .be
.replaced? .- .(correct .answer) .-All .of .the .belts .should .be .replaced.
Does .a .solenoid .valve .vary .or .control .the .flow .of .refrigerant? .- .(correct .answer) .-No.
What .accessory .meters .and .controls .the .flow .of .refrigerant .into .the .evaporator? .-
.(correct .answer) .-The .TEV .(Metering .Device).
What .will .occur .if .you .use .an .automatic .expansion .valve .with .a .variable .load? .-
.(correct .answer) .-You .will .starve .the .evaporator.
What .does .an .automatic .expansion .valve .do? .- .(correct .answer) .-It .maintains .a
.constant .evaporator .pressure.
What .could .cause .the .evaporator .to .not .respond .to .the .adjustments .of .the .TEV? .-
.(correct .answer) .-Oil .logged .on .the .low .side.
, What .can .non-condensible's .cause? .- .(correct .answer) .-High .head .pressure.
When .will .compressor .motor .horsepower .increase? .- .(correct .answer) .-It .will .increase
.as .the .head .pressure .increases.
When .will .compressor .motor .horsepower .decrease? .- .(correct .answer) .-As .the
.suction .pressure .increases.
When .using .a .brine .solution .in .a .system .what .can .be .used .to .prevent .rusting? .-
.(correct .answer) .-Di-Chromate .Tablets.
What .would .cause .a .Halide .torch .flame .to .turn .yellow? .- .(correct .answer) .-A .clogged
.sample .tube.
What .is .the .purpose .of .having .2 .compressors .in .a .cascade .system? .- .(correct
.answer) .-To .operate .and .very .low .temperatures .and .avoid .high .compression .ratio.
Why .is .a .pressure .relief .valve .better .than .a .fusible .plug? .- .(correct .answer) .-Because
.it .can .be .re-seated .and .is .cost .efficient.
What .could .cause .compressor .knocking? .- .(correct .answer) .-Liquid .refrigerant
.slugging .the .compressor.
What .would .occur .if .a .TEV'S .spring .were .to .break? .- .(correct .answer) .-It .would .flood
.the .evaporator .and .raise .the .suction .pressure .because .a .TEV .uses .spring .pressure
.as .its .closing .force. .Thus, .if .the .spring .does .not .close .the .TEV .refrigerant .will
.constantly .be .metered .into .the .evaporator.
What .is .the .purpose .of .the .TEV .equalizer .line? .- .(correct .answer) .-It .compensates .for
.the .pressure .drop .in .the .evaporator. .Simply .put, .it .equalizes .pressure .drop .lost
.across .the .evaporator.
What .should .be .done .when .installing .copper .pipe .and .a .90 .degree .elbow .is .needed?
.- .(correct .answer) .-You .should .BRAZE .in .a .FACTORY .MADE .90 .degree .elbow.
What .is .the .purpose .of .a .service .valve .stem .cap? .- .(correct .answer) .-It .protects .the
.valve .from .refrigerant .leakage.
What .advantage .do .semi .hermetic .compressor's .have .over .hermetic .compressor's? .-
.(correct .answer) .-Semi .hermetic .compressor's .can .be .serviced.
What .happens .when .using .portable .compressor .recovery .unit .to .remove .vapor? .-
.(correct .answer) .-The .vapor .density .is .decreased.
