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Refrigerant Machine Operator Practical > Refrigerant Machine Operator Practice Test #2 > Flashcards

Refrigerant Machine Operator Practice Test #2 Flashcards

1
Q

WHEN RECOVERING R-22, WHAT COLOR WOULD THE CYLINDER BE THAT YOU ARE STORING THE REFRIGERANT IN?

YELLOW TOPS

WHITE TOPS

GREEN TOPS

GRAY TOPS

A

Yellow tops

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2
Q

IN A CENTRIFUGAL THREE STAGE COMPRESSOR:

PRESSURE INCREASES WITH EACH STAGE

IMPELLERS ARE SAME SIZE

IMPELLERS INCREASE WITH EACH STAGE

BOTH A AND B ARE CORRECT

A

BOTH A AND B ARE CORRECT

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3
Q

THE ACCESSORIES ON THE LIQUID LINE ARE IN WHAT ORDER?

SOLENOID VALVE, DRIER, AND SIGHT-GLASS

RECEIVER, DRIER, SOLENOID VALVE, AND SIGHT-GLASS

MUFFLER, DRIER, SIGHT-GLASS AND SOLENOID VALVE

ACCUMULATOR, MUFFLER, DRIER, SIGHT-GLASS

A

RECEIVER, DRIER, SOLENOID VALVE, AND SIGHT-GLASS

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4
Q

AN OIL WITH LOW VISCOSITY WOULD:

NOT BE USED FOR REFRIGERATION

BE USED FOR ENGINE/MOTORS

BE USED FOR AIR CONDITIONING

BOTH B AND C ARE CORRECT

A

NOT BE USED FOR REFRIGERATION

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5
Q

SUPERHEATED VAPOR FLOWING INTO A RECIPROCATING COMPRESSOR PROTECTS THE COMPRESSOR PARTS AGAINST LIQUID INTAKE. OF THE FOLLOWING, ONE OF THE PROBLEMS ASSOCIATED WITH SUPERHEAT IS THAT:

NON-CONDENSABLES ARE MORE PRONE TO COLLECT IN THE SYSTEM

FROST MAY DEVELOP IN THE SUCTION LINE

IT WILL DECREASE THE CAPACITY OF THE COMPRESSOR AND THE REFRIGERATION MACHINE

THE COMPRESSOR HEAD PRESSURE DROPS TOO LOW

A

IT WILL DECREASE THE CAPACITY OF THE COMPRESSOR AND THE REFRIGERATION MACHINE

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6
Q

WHAT IS THE CUBIC FEET IF A 20 FT LONG 6 FT VESSEL ON THE EVAPORATOR?

120 CUBIC FEET

565 CUBIC FEET

4,235 CUBIC FEET

4,710 CUBIC FEET

A

565 CUBIC FEET

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7
Q

THE SUCTION AND DISCHARGE VALVE IN A RECIPROCATING COMPRESSOR ARE POSITIONED:

OVER VALVE PLATE

UNDER VALVE PLATE

BOTH UNDER AND OVER VALVE PLATE

NONE OF THE ABOVE

A

BOTH UNDER AND OVER VALVE PLATE

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8
Q

BECAUSE OF THE LATENT HEAT LOAD, REFRIGERATION MACHINE OPERATOR WAS INSTRUCTED TO START THE RECIPROCATING PLANT FOR AIR CONDITIONING. OF THE FOLLOWING ACCORDING TO RECOMMENDED PRACTICE, THE FIRST THING TO DO IS

TURN ON CHILLED WATER PUMPS AND OPEN THE BYPASS TO LIGHTER LOAD

INSTALL LARGER FUSE TO TAKE THE INITIAL LOAD, AND THEN TURN ON THE COOLING TOWER FANS

TURN ON CHILLED WATER PUMP, CONDENSER WATER PUMPS AND COOLING TOWER FANS

SET THE THERMOSTAT A FEW DEGREES HIGHER

A

TURN ON CHILLED WATER PUMP, CONDENSER WATER PUMPS AND COOLING TOWER FANS

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9
Q

AN OPERATOR SUSPECTS THAT A VERTICAL CHECK VALVE ON A DISCHARGE OF A CENTRIFUGAL PUMP IS DEFECTIVE, THIS IS A CONDENSER PUMP AND ONE OF THE THREE PUMPS IN PARALLEL. IF THE SUSPICION IS TRUE AND THE CHECK VALVE FAILS TO SEAT WHEN REQUIRED, THE PUMP AND CONNECTING PIPING WILL MOST LIKE BE DAMAGED WHEN:

LUBRICATING THE PUMP

AFTER HAVING BLED AIR FROM THE PUMP CASING PETCOCK

STARTING UP AN ADDITIONAL PUMP

SHUTTING THE PUMP DOWN

A

STARTING UP AN ADDITIONAL PUMP

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10
Q

A CONDENSER IS 20’ LONG AND 6’ IN DIAMETER, WHAT IS THE VOLUME IN GALLONS IF 7.48 GALLONS IS 1 CU/FT?

565

4227

1808

1205

A

4227

Volume of cylinder is V=(pi)r^2(h)

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11
Q

AN OPERATOR OBSERVES A READING OF 60°C ON A REFRIGERATING UNIT. THE SAME READING IN FAHRENHEIT SCALE WOULD BE CLOSER TO

140

185

155

170

A

140

F=(C*(9/5))+32

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12
Q

IN A 3 STAGE CENTRIFUGAL CHILLER, WHAT HAPPENS TO THE PRESSURE AS IT REACHES THE FINAL STAGE?

INCREASES

DECREASES

SPEED CHANGES NOT PRESSURE

VOLUME CHANGES NOT PRESSURE

A

INCREASES

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13
Q

REGARDLESS OF SAFETY CLASSIFICATION OF THE REFRIGERANT IN USE, IN THE EVENT OF REFRIGERANT ESCAPE, THE RMO SHOULD BE AWARE OF:

A REFRIGERANT FIRE

REFRIGERANT POISONING

OXYGEN DEPRIVATION

ATMOSPHERIC SUPERHEATING

A

OXYGEN DEPRIVATION

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14
Q

WHAT IS THE STATE OF REFRIGERANT AS IT LEAVES THE COMPRESSOR AND AS IT LEAVES THE CONDENSER:

SUPERHEATED VAPOR AND SUPERHEATED LIQUID

SUPERHEATED VAPOR AND WARM SUB-COOLED LIQUID

SATURATED VAPOR AND COLD SUB-COOLED LIQUID

SATURATED VAPOR AND WARM SUB-COOLED LIQUID

A

SUPERHEATED VAPOR AND WARM SUB-COOLED LIQUID

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15
Q

thing is used for ____

A

recovery

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16
Q

THE MOST IMPORTANT REASON TO USE 2 COMPRESSORS IN A CASCADE SYSTEM IS TO:

ACCOMPLISH LOWER TEMPERATURE

PERMIT THE USE OF INEXPENSIVE LUBRICATING OIL

AVOID THE NEED FOR VERY HIGH COMPRESSION RATIOS

DIVIDE THE COOLING LOAD BETWEEN 2 COMPRESSORS

A

ACCOMPLISH LOWER TEMPERATURE

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17
Q

IN RELATION TO THE SUCTION PRESSURE OF A COMPRESSOR, THE READING IN THE OIL PRESSURE GAUGE SHOULD READ:

15-30 PSI LOWER

60-90 PSI HIGHER

15-30 PSI HIGHER

30-60 PSI LOWER

A

15-30 PSI HIGHER

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18
Q

CLEARANCE VOLUME:

AFFECTS COMPRESSOR CAPACITY

IS THE SPACE THAT TRAPS LIQUID REFRIGERANT

VARIES, DEPENDING ON COMPRESSOR SPEED

IS THE SAME ON ALL COMRPESSORS

A

AFFECTS COMPRESSOR CAPACITY

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19
Q

THE ADVANTAGE OF FORCED DRAFT OVER NATURAL DRAFT COOLING TOWER IS:

THE POSSIBILITY OF LOWER WATER OUT TEMP

THERE IS NO DEPENDENCE ON NATURAL WIND VELOCITY

USE OF A SMALLER TOWER SIZE

ALL OF THE ABOVE

A

ALL OF THE ABOVE

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20
Q

WITH AN INDUCED DRAFT COOLING TOWER, WHAT IS THE LOWEST TEMPERATURE ATTAINABLE FOR A COOLING TOWER?

WET BULB EQUAL TO DRY BULB

DRY BULB SLIGHTLY LOWER THAN WET BULB

DRY BULB HIGHER THAN WET BULB

WET BULB CAN NEVER BE LOWER THAN DRY BULB

A

DRY BULB HIGHER THAN WET BULB

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21
Q

A THERMAL BULB IS ATTACHED TO THE SUCTION PIPE BETWEEN THE EVAPORATOR COIL AND THE COMPRESSOR COVERED BY AN INSULATING LINE. ASSUMING THE MACHINE ROOM IS 85°F, UNRAVELING OF THE INSULATION WOULD RESULT IN:

ADEQUATE SUPERHEAT

STARVED EVAPORATOR

EXCESSIVE SUPERHEAT

FLOODED EVAPORATOR

A

FLOODED EVAPORATOR

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22
Q

IF THE LOW PRESSURE CUTOUT CYCLES THE COMPRESSOR OFF, WHAT STARTS THE COMPRESSOR AGAIN?

SOLENOID VALVE

HIGH PRESSURE CUT OUT

LOW PRESSURE CUT OUT

THERMOSTAT

A

LOW PRESSURE CUT OUT

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23
Q

THE FOLLOWING MOST ACCURATE STATEMENT REGARDING COMPRESSOR MOTORS THAT RUN IN REFRIGERANT ATMOSPHERE IS THAT THEY:

MAY USE INTERNAL RUBBER CUSHIONS

MAY BE REPAIRED ON SITE WHEN THEY MALFUNCTION

USE MATERIALS TAILORED TO THE REFRIGERANT

USE SAME MATERIALS A PUMP IN AIR

A

USE MATERIALS TAILORED TO THE REFRIGERANT

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24
Q

WHEN A COMPRESSOR IS RUNNING FINE AT FULL FLOW AND YOU THROTTLE DOWN FLOW CAUSING THE COMPRESSOR TO STOP RUNNING NORMAL (SHORT CYCLE), WHY WOULD THIS HAPPEN?

DIRTY FILTER/STRAINER

AIR GETTING IN SEALS

LOW PRESSURE CUT OUT

HIGH HEAD PRESSURE

A

LOW PRESSURE CUT OUT

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25
Q

WHEN AN EVAPORATOR IS NOT EQUIPPED WITH AN EQUALIZER LINE, YOU WOULD MOST LIKELY FIND:

FEELER BULB PLACED IN DIFFERENT AREA

A DISTRIBUTOR

AN AUTOMATIC EXPANSION VALVE

BOTH HIGH AND LOW SIDE PRESSURES IDENTICAL

A

A DISTRIBUTOR

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26
Q

REMOVING THE INSULATION ON THE SUCTION LINE, WITH THE ENGINE TEMPERATURE AT 85°F, WHAT WILL OCCUR?

FLOODED EVAPORATOR

STARVED EVAPORATOR

EXCESSIVE SUPERHEAT

LOW SUPERHEAT

A

EXCESSIVE SUPERHEAT

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27
Q

DURING A HOT WEEKEND, AN RMO IS INSTRUCTED TO START AN ADDITIONAL RECIPROCATING MACHINE. THE SEQUENCE OF ACTIONS ON START UP WOULD MOST LIKELY BE

CHECK COMPRESSOR OIL, START COOLING TOWER FANS, CHECK VALVES ARE IN CORRECT POSITION, TURN ON MACHINE, START CHILLER AND CONDENSER WATER PUMPS

START CHILLER AND CONDENSER WATER PUMPS, START COOLING TOWER FANS, CHECK COMPRESSOR OIL LEVELS, CHECK THAT VALVES ARE IN CORRECT POSITION, TURN MACHINE ON

TURN MACHINE ON, CHECK VALVES ARE IN CORRECT POSITION, START TOWER FANS, CHECK COMPRESSOR OIL LEVELS, START CHILLER AND CONDENSER WATER PUMPS

CHECK VALVES ARE IN CORRECT POSITION, START COOLING WATER TOWER FANS, START MACHINE, START CHILLER AND CONDENSER WATER PUMPS, CHECK COMPRESSOR OIL LEVELS

A

START CHILLER AND CONDENSER WATER PUMPS, START COOLING TOWER FANS, CHECK COMPRESSOR OIL LEVELS, CHECK THAT VALVES ARE IN CORRECT POSITION, TURN MACHINE ON

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28
Q

A WATER REGULATING VALVE IS INSTALLED IN A WATER COOLED CONDENSER. THE OPERATING FORCE ON THIS VALVE IS RESPONDENT TO:

HIGH SIDE PRESSURE

CHILLED WATER TEMPERATURE

CIRCULATING WATER PRESSURE THROUGH THE CONDENSER

MANUAL OPERATION

A

HIGH SIDE PRESSURE

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29
Q

A REFRIGERATION UNIT IS MEASURED IN:

WATTS

VOLTS

BTUs

TEMPERATURE

A

BTUS

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30
Q

THE REFRIGERATION UNIT WHICH YOU HAVE BEEN ASSIGNED TO IS BEING TAKEN OUT OF SERVICE FOR MAJOR REPAIRS. YOU HAVE BEEN ASSIGNED TO WITHDRAW REFRIGERANT FOR STORAGE IN SUITABLE CONTAINERS. ACCORDING TO THE NYC FIRE LAW HANDBOOK YOU MUST ENSURE THAT CONTAINERS:

ARE APPROVED BY THE U.S. DEPT. OF TRANSPORTATION

ARE APPROVED BY THE FACILITIES MANAGER

DO NOT WEIGH MORE THAN 200 LBS WHEN FILLED

DO NOT EXCEED 55 GALLONS IN CAPACITY

A

ARE APPROVED BY THE U.S. DEPT. OF TRANSPORTATION

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31
Q

WHAT IS 29.92” HG IN KPA

101.3

101.28

101.26

103.2

A

101.3

1 HG” = 3.386

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32
Q

OF THE FOLLOWING ONE OF THE PRIMARY REASONS FOR THE INSULATION OF A CRANKCASE BREATHER LINE IS:

INCREASE THE COMPRESSOR EFFICIENCY

TO PREVENT OIL SLUGGING IN THE COMPRESSOR

KEEP THE SHAFT PACKING LUBRICATED

TO PREVENT REFRIGERANT FROM ENTERING THE COMPRESSOR SUCTION

A

TO PREVENT OIL SLUGGING IN THE COMPRESSOR

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33
Q

THE MECHANISM SITTING ABOVE THE EVAPORATOR IS KNOWN AS

ECONOMIZER

PURGE UNIT

AIR BLEED

PRESSURE RELIEF VALVE

A

PURGE UNIT

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34
Q

IF YOU WERE RUNNING THREE COMPRESSORS, WHICH BEST DESCRIBES THE STATE OF REFRIGERANT LEAVING THE THIRD EVAPORATOR COIL?

MOSTLY LIQUID, SOME VAPOR

MOSTLY VAPOR, SOME LIQUID

SUPERHEATED VAPOR

HIGHLY SUPERHEATED VAPOR

A

SUPERHEATED VAPOR

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35
Q

THE RUPTURE DISK IS ALWAYS PIPED INTO THE

HIGH SIDE

LOW SIDE

EITHER SIDE OF SYSTEM

NEITHER SIDE SYSTEM

A

LOW SIDE

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36
Q

WHEN DRY BULB IS 75°F AND WET BULB IS 75°F:

NOT POSSIBLE

VERY LOW HUMIDITY

THERMOMETER IS DEFECTIVE

100% RELATIVE HUMIDITY

A

100% RELATIVE HUMIDITY

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37
Q

WHILE DOING A ROUTINE INSPECTION, THE RMO NOTICED THE BULB OF THE TEV ON THE FLOOR, THE OPERATOR SHOULD ATTACH THE BULB AT:

CENTER OF THE COIL

EXPANSION VALVE OUTLET

END OF COIL

3/4 AWAY TOWARDS THE END OF THE COIL

A

END OF COIL

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38
Q

A RMO NOTICES EXCESSIVE CYCLING OF THE TEMPERATURE CONTROL FOR A RECIPROCATING COMPRESSOR REFRIGERATION UNIT. THE CRANKCASE TEMP IS HIGH, THE COMPRESSOR DISCHARGE TEMP IS LOW AND THE SUCTION LINE IS HIGH, OF THE FOLLOWING THE ONE THAT MAY BE CAUSING THIS SET OF CONDITIONS IS:

PURGE UNIT OPERATION

AN EXPANSION VALVE THAT IS OPEN TOO WIDE

FAULTY COMPRESSOR VALVES

CONDENSER OPERATION, DIRTY TUBES OR COOLING WATER CONTROL

A

CONDENSER OPERATION, DIRTY TUBES OR COOLING WATER CONTROL

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39
Q

CONCERNING LEAKAGE, WHICH STATEMENT IS MOST CORRECT?

GATE VALVE CAUSES LESS LEAKAGE

GLOBE VALVES CAUSES MORE LEAKAGE

ALL VALVES ARE THE SAME

GATE VALVES CAUSES MORE LEAKAGE

A

GATE VALVES CAUSES MORE LEAKAGE

40
Q

WHEN A COMPRESSOR IS SAID TO HAVE A SAFETY HEAD THIS MEANS

COMPRESSOR OPERATES WITH NORMAL PRESSURES

COMPRESSOR OPERATES WITH LOW PRESSURES

COMPRESSOR HAS PRESSURE RELIEF VALVE

COMPRESSOR HAS HIGH PRESSURE CUT OUT

A

COMPRESSOR HAS PRESSURE RELIEF VALVE

41
Q

COMPOUND GAUGES CAN MEASURE:

ABOVE ATMOSPHERIC

BELOW ATMOSPHERIC

TEMPERATURE

ALL OF THE ABOVE

A

ALL OF THE ABOVE

42
Q

THE FOLLOWING IS AN EXAMPLE OF AN “INLINE” REFRIGERANT CLEANING SYSTEM WHICH MAY BE USED WITH A CENTRIFUGAL COMPRESSOR CONTAINING R-123 REFRIGERANT IS:

REFRIGERANT RECOVERY

REFRIGERANT DISPOSAL

REFRIGERANT RECLAIMING

REFRIGERANT RECYCLING

A

REFRIGERANT RECYCLING

43
Q

WHAT REFRIGERANTS ARE YOU NOT ABLE TO DUMP?

CFC

HCFC

HFC

ANY REFRIGERANT CONTAINING CHLORINE OR FLUORINE

A

ANY REFRIGERANT CONTAINING CHLORINE OR FLUORINE

44
Q

WHEN OPERATING A RECIPROCATING REFRIGERATION SYSTEM WITH A BELT DRIVEN COMPRESSOR, AN RMO NOTICES THAT ONE OF THE 4 BELTS IS BROKEN. OF THE FOLLOWING, THE MOST ADVISABLE COURSE OF ACTION FOR THE RMO WOULD BE TO

PUT MORE GREASE ON THE REMAINING BELTS

REPLACE ALL 4 BELTS WITH A NEW SET

REPLACE THE BROKEN BELT ONLY

OPERATE WITH THE 3 REMAINING BELTS

A

REPLACE ALL 4 BELTS WITH A NEW SET

45
Q

AN OPERATOR CONFIRMS THAT A CHILLER WATER PUMP IN A REFRIGERATING SYSTEM EMPLOYING R-123 IS CAVITATING, OF THE FOLLOWING, THE MOST LIKELY CAUSE FOR THIS CONDITION IS

MALFUNCTIONING OF THE WATER MAKE UP FLOAT VALVE

TOO MUCH TIME IN BETWEEN PUMP SERVICING

OPERATING AT SUSTAINED HIGH LOADS

LOWERING THE CHILLED WATER TEMPERATURE

A

MALFUNCTIONING OF THE WATER MAKE UP FLOAT VALVE

46
Q

AN OPERATOR READS THE VALVE TAG ON A PRESSURE RELIEF VALVE AND NOTICES THAT THE VALVE IS SET TO UNSEAT AT AN EVAPORATOR PRESSURE OF 15 PSI, THE CORRESPONDING SET PRESSURE IN INCHES HG IS

18

14

20

30.3

A

30.3

1 psi = 2.036 hg”

47
Q

ACCORDING TO THE NYC FIRE CODE CLASSIFICATION OF REFRIGERANTS, AMMONIA AND SULPHER DIOXIDE AR GROUPED INTO:

GROUP 2

GROUP 4

GROUP 1

GROUP 3

A

GROUP 2

48
Q

A CENTRIFUGAL CHILLER HAS A SUCTION PRESSURE OF 18” HG VACUUM AND DISCHARGE PRESSURE OF 6 PSIG. WHAT IS THE COMPRESSION RATIO OF THIS UNIT?

3.50

2.96

1.75

2.76

A

3.50

1 ich of mercury is equal to 0.491 psig. So the suction pressure is 18” in vacuum * 0.491 psig/inch of mercury = 8.838 psig. Now calculate compression ratio, 6 psig / 8.838 psig = 0.679

??????????????????????????

49
Q

WHAT IS THE MAXIMUM PERCENTAGE THAT A REFRIGERANT CAN BE STORED IN An EPA CYLINDER?

80%

70%

90%

100%

A

80%

50
Q

WHEN YOU PLAN ON OVERHAULING A SYSTEM AND YOU HAVE RECOVERED ALL LIQUID REFRIGERANT, WHAT IS NEXT?

GO AHEAD AND DO THE WORK

RECOVER ALL VAPOR, THEN DO WORK

SEND LIQUID NITROGEN THROUGH

EVACUATE SYSTEM

A

RECOVER ALL VAPOR, THEN DO WORK

51
Q

A RECIPROCATING SYSTEM USING AN EVAPORATIVE CONDENSER, THE MUFFLER IS INSTALLED BETWEEN THE:

EVAPORATOR AND CONDENSER

RECEIVER AND EXPANSION VALVE

COMPRESSOR AND EVAPORATIVE CONDENSER

RECEIVER AND CONDENSER

A

COMPRESSOR AND EVAPORATIVE CONDENSER

52
Q

A LOW PRESSURE REFRIGERATION SYSTEM HAS A PIN HOLE IN THE EVAPORATOR. WHAT IS THE MOST LIKELY RESULT?

HIGH HEAD PRESSURE

FROST AROUND LEAK AREA

HIGH CONDENSER WATER PRESSURE

LOW CONDENSER PRESSURE

A

HIGH HEAD PRESSURE

53
Q

WHAT SHAFT SEAL PREVENTS VAPOR FROM LEAKING OUT OF COMPRESSOR?

STUFFING BOX

ELECTRO-MECHANICAL SEAL

MECHANICAL SEAL

ALL OF THE ABOVE

A

STUFFING BOX

54
Q

WHEN THERE IS A 5 LB PRESSURE DROP ACROSS EVAPORATOR, YOU NEED AN EXTERNAL EQUALIZER LINE, WHAT HAPPENS IF IT DISCONNECTS

EXCESSIVE SUPERHEAT

EVAPORATOR WOULD STARVE

EVAPORATOR WOULD FLOOD

TEV WOULD NOT FUNCTION

A

EVAPORATOR WOULD STARVE

55
Q

IF UNLOADERS WERE TO FAIL IN THE UNLOADED POSITION, WHAT HAPPENS IN A SYSTEM USING RECIPROCATING COMPRESSOR?

THE EVAPORATOR WILL STARVE

CAUSE HIGH SUPERHEAT

NOT ENOUGH REFRIGERANT TO COIL

ALL OF THE ABOVE

A

ALL OF THE ABOVE

56
Q

THE RATIO OF ACTUAL PRESSURE OF WATER VAPOR IN THE ATMOSPHERE TO THE SATURATION PRESSURE / TEMPERATURE IS CALLED:

ABSOLUTE HUMIDITY

HUMIDITY EFFECT

PARTIAL PRESSURE

RELATIVE HUMIDITY

A

RELATIVE HUMIDITY

57
Q

WHAT IS A METHOD USED TO CALIBRATE A THERMOMETER?

PLACE THERMOMETER IN CUP OF ICE

PLACE THERMOMETER IN SUPERHEATED STEAM

LOWER TEMPERATURE ON THERMOMETER

RAISE TEMPERATURE ON THERMOMETER

A

PLACE THERMOMETER IN CUP OF ICE

58
Q

OF THE FOLLOWING CHARACTERISTICS OF REFRIGERANT, THE ONE THAT BEST DESCRIBES REFRIGERANT 22 IS:

ODORLESS WHEN MIXED WITH AIR

AN ETHER LIKE ODOR WHEN MIXED WITH AIR

EXPLOSIVE WHEN MIXED WITH AIR

BOILS AT HIGHER TEMP THAT R-12

A

ODORLESS WHEN MIXED WITH AIR

59
Q

REGARDING FIRE SAFETY ANSI/ASHRAE, WHICH CLASSIFICATION INDICATES THE LEAST FLAMMABILITY AND LEAST TOXICITY?

A1

B2

A2

B1

A

A1

60
Q

THE METERING DEVICE USED IN A CONDENSER IS A HIGH SIDE FLOAT, THIS DEVICE WILL:

CONTROL THE AMOUNT OF WATER IN CONDENSER

CONTROL THE AMOUNT OF REFRIGERANT IN CONDENSER

KEEPS A CONSTANT PRESSURE

KEEPS A CONSTANT TEMPERATURE

A

CONTROL THE AMOUNT OF REFRIGERANT IN CONDENSER

61
Q

THE DIVIDING LINE BETWEEN THE HIGH AND LOW SIDES OF THE REFRIGERATION SYSTEM IS

THE CONNECTION BETWEEN THE COMPRESSOR AND CONDENSER

NEEDLE VALVE MECHANISM

COMPRESSOR OUTLET AND THE ORIFICE OF THE METERING DEVICE

CENTER PLATE OF THE REFRIGERATION MECHANISM

A

COMPRESSOR OUTLET AND THE ORIFICE OF THE METERING DEVICE

62
Q

THERE IS AN AUTOMATIC WATER REGULATING VALVE ON A RECIPROCATING CHILLER. WATER IS ENTERING THE CONDENSER AT 88°F. YOU KNOW THERE IS NO SCALE AND THE TUBES ARE NOT COVERED WITH FILM. WHAT CAN BE CAUSING THIS CONDITION?

HIGH HEAD PRESSURE

LOW SUCTION PRESSURE

WATER VALVE STUCK OPEN

WATER VALVE STUCK CLOSED

A

WATER VALVE STUCK OPEN

63
Q

A FUSIBLE PLUG MELTS AT

450°F

280°F

212°F

800°F

A

280°F

64
Q

WHILE OPERATING AN R-12 RECIPROCATING SYSTEM, THE RMO NOTICED THE OIL FOAMING IN THE CRANKCASE, THIS CONDITION MOST LIKELY WOULD HAVE BEEN CAUSED BY:

ADDITION FROM FREON

SUDDEN DROP IN OIL TEMPERATURE

SUDDEN DROP IN CRANKCASE PRESSURE

ADDITION OF OIL TO THE CRANKCASE

A

SUDDEN DROP IN CRANKCASE PRESSURE

65
Q

IF A LOW SIDE FLOAT IS BEING USED:

PRESSURE WILL BE CONSTANT

IT WILL CONTROL REFRIGERANT FLOW

IT WILL CONTROL WATER FLOW

TEMPERATURE IS CONSTANT

A

IT WILL CONTROL REFRIGERANT FLOW

66
Q

WHEN CHARGING A CENTRIFUGAL SYSTEM THE POSITION OF THE VALVE IS:

FRONT SEATED

BACK SEATED

CRACKED OFF THE BACK SEAT

CLOSED

A

BACK SEATED

67
Q

WHAT DOES CENTRIFUGAL COMPRESSOR GENERATE INSIDE?

HIGH PRESSURE, LOW VOLOCITY

HIGH VOLUME, LOW PRESSURE

LOW VELOCITY, LOW PRESSURE

HIGH VELOCITY, HIGH PRESSURE

A

HIGH VOLUME, LOW PRESSURE

68
Q

THE HEAT THAT BOILS OFF IN A CONDENSER IS:

LATENT HEAT

SENSIBLE HEAT

SUPERHEAT

ALL OF THE ABOVE

A

LATENT HEAT

69
Q

BUBBLES IN THE SIGHT GLASS ARE MOST LIKELY CAUSED BY:

AN OVERCHARGED SYSTEM

NON-CONDENSEABLE GASES

LIGHT LOAD ON THE PLANT

PARTIALLY PLUGGED FILTER/DRIER

A

PARTIALLY PLUGGED FILTER/DRIER

70
Q

IF HAD TO INSTALL A SOLENOID VALVE TO A SYSTEM WHICH USES 110 VOLTS AND NEEDED TO CONVERT IT TO 24 VOLTS, WHAT WOULD YOU USE?

STEP UP TRANSFORMER

STEP DOWN TRANSFORMER

AC TO DC RECTIFICATION

REWIRE CIRCUIT WITH SMALLER GAUGE WIRE

A

STEP DOWN TRANSFORMER

71
Q

AN OPERATOR VERIFIES THAT A CONDENSER WATER PUMP IS CAVITATING IN A REFRIGERATION SYSTEM EMPLOYING R-22 REFRIGERANT. OF THE FOLLOWING THE MOST LIKELY CAUSE FOR THIS CONDITION IS:

AIR LEAKS THROUGH THE PUMP PACKING

OPERATING AT SUSTAINED HIGH LOADS

FAULTY COOLING TOWER WATER LEVEL CONTROLLER

TOO LONG A PERIOD BETWEEN PUMP SERVICING

A

FAULTY COOLING TOWER WATER LEVEL CONTROLLER

72
Q

OIL FLASHPOINT TEMPERATURE IN THE COMPRESSOR SHOULD BE:

LOWER THAN THE HEAT OF COMPRESSION

HIGHER THAN THE HEAT OF COMPRESSION

EQUAL TO THE HEAT OF COMPRESSION

EQUAL TO THE HEAT ABSORBED

A

HIGHER THAN THE HEAT OF COMPRESSION

73
Q

HOW LOW CAN CHILLER WATER TEMPERATURE BE?

32°F

33°F

38°F

42°F

A

33°F

74
Q

WHEN THE TEMPERATURE AND THE LOAD INCREASE AND YOU NEED TO ADD ANOTHER PUMP ONLINE, YOU WOULD:

CLOSE BOTH SUCTION AND DISCHARGE

OPEN BOTH SUCTION AND DISCHARGE

OPEN SUCTION AND THROTTLE DISCHARGE

OPEN DISCHARGE BYPASS AND CLOSE SUCTION

A

OPEN SUCTION AND THROTTLE DISCHARGE

75
Q

WHEN WILL THE BTUs ABSORBED BY THE CONDENSING WATER BE THE GREATEST?

LOW CONDENSER TEMPERATURE, LOW CONDENSER WATER TEMPERATURE

HIGH CONDENSER TEMPERATURE, HIGH CONDENSER WATER TEMPERATURE

HIGH CONDENSER TEMPERATURE, LOW CONDENSER WATER TEMPERATURE

LOW CONDENSER TEMPERATURE, HIGH CONDENSER WATER TEMPERATURE

A

HIGH CONDENSER TEMPERATURE, LOW CONDENSER WATER TEMPERATURE

76
Q

AN OPERATOR NOTICES THAT A CENTRIFUGAL PUMP OPERATES SATISFACTORILY WHEN DELIVERING AT FULL DISCHARGE, BUT LOSES WATER FLOW IF THROTTLED. THE OPERATOR WOULD MOST ACCURATELY ASSUME THAT THIS CONDITION IS DUE TO:

WATER HAMMER

CLOGGED STRAINER IN PUMP INLET

POOR BEARING LUBRICATION

AIR LEAKS IN THE PUMP

A

CLOGGED STRAINER IN PUMP INLET

77
Q

ASSUME THAT A NEW VALVE PLATE HAS BEEN INSTALLED WHILE THEY ARE REPAIRING A RECIPROCATING COMPRESSOR IN A REFRIGERATING PLANT. THE INSTALLATION OF A NEW VALVE PLATE WILL REQUIRE THE REPLACEMENT OF

ALL VALVE PLATES, SPRINGS AND SOME VALVE SEATS

ALL VALVE AND VALVE SEATS

VALVE SEATS ONLY

SUCTION VALVES ONLY

A

ALL VALVE AND VALVE SEATS

78
Q

A RMO IS LOGGING READINGS FROM A RECIPROCATING COMPRESSOR REFRIGERATING UNIT. THE CRANKCASE AND COMPRESSOR DISCHARGE TEMPERATURE HAVE DROPPED SIGNIFICANTLY AND SUCTION LINE PRESSURE IS HIGH. OF THE FOLLOWING THE ONE THAT MAY CAUSE THIS SET OF CONDITION IS:

COMPRESSOR CYCLING

AN EXPANSION VALVE WHICH IS CLOSED TOO MUCH

AN EXPANSION VALVE WHICH IS OPEN TO WIDE

FAULTY COMPRESSOR VALVES

A

FAULTY COMPRESSOR VALVES

79
Q

THE CYLINDER UNLOADER CONTROLS CAPACITY, IS THERE ANY OTHER FUNCTION IT MAY HAVE?

ASSIST WITH COMPRESSOR SHUT DOWN

ASSIST WITH COMPRESSOR START UP

THERE IS NO OTHER FUNCTION

RELEASES PRESSURE

A

ASSIST WITH COMPRESSOR START UP

80
Q

THE CONDENSER THAT USES AIR AND WATER FOR COOLING IS THE:

AIR COOLED

WATER COOLED

EVAPORATIVE

BOTH A AND B ARE CORRECT

A

EVAPORATIVE

81
Q

ASSUMING THAT A REFRIGERATION PLANT USES A HORIZONTAL SHELL AND TUBE CONDENSER WITH THE WATER IN THE TUBES AND THE REFRIGERANT IN THE SHELL. IN CONTROLLING THE OPERATION OF THE CONDENSER, THE OPERATOR SHOULD TAKE INTO ACCOUNT THAT MOST LIKELY THE HEAT TRANSFER RATE BTU/PER SQ FT PER SECOND IN THE CONDENSER WILL:

SHOW THE LEAST BENEFIT FOR DESCALING TUBES AT HIGH WATER VELOCITIES

INCREASE WITH THE VELOCITY OF THE WATER IN THE TUBES

INCREASE THE LOWER LOG MEAN TEMPERATURE DIFFERENCE

SHOW ONLY A SMALL INCREASE IF THE TUBES ARE DESCALED

A

INCREASE WITH THE VELOCITY OF THE WATER IN THE TUBES

82
Q

FLOODED EVAPORATORS HAVE HIGH HEAT TRANSFER PER SQUARE FOOT, WHAT MAY BE A DISADVANTAGE?

REQUIRES A SMALLER CHARGE

REQUIRES A HIGHER CHARGE

REQUIRES A USE OF A TXV FOR PROPER FEED

WATER HAS TO BE DRAINED DAILY

A

REQUIRES A HIGHER CHARGE

83
Q

A HERMETIC COMPRESSOR IS OPERATING WITH A LOW REFRIGERANT CHARGE. WHAT IS THE MOST LIKELY EFFECT THIS CONDITION WOULD HAVE ON THE COMPRESSOR?

HEAD PRESSURE WOULD RISE

COMPRESSOR WOULD OPERATE AT HIGHER TEMPERATURE

HAVE NO EFFECT ON THE COMPRESSOR

OIL PRESSURE WOULD RISE

A

COMPRESSOR WOULD OPERATE AT HIGHER TEMPERATURE

84
Q

IN ADDITION TO REGULATING THE REFRIGERANT FLOW ACCORDING TO THE NEEDS OF THE SYSTEM, METERING DEVICES ALSO SERVE TO:

INCREASE COMPRESSOR CAPACITY

HOLD SYSTEM TO A CONSTANT LOAD

RESTRICT FLOW OF REFRIGERANT FROM THE HIGH SIDE TO LOW SIDE

SHED LOAD AS LOAD INCREASES

A

RESTRICT FLOW OF REFRIGERANT FROM THE HIGH SIDE TO LOW SIDE

85
Q

ELECTRIC DEVICES MAY BE USED TO PROVIDE BUILT IN DEFROSTING OF REFRIGERATING MACHINE EVAPORATOR UNITS. THESE ARE CLASSIFIED AS:

RELAYS

INDUCTION COILS

CAPACITORS

RESISTORS

A

RESISTORS

86
Q

LATENT HEAT AND REFRIGERATION EFFECT ARE USUALLY LISTED AS REFRIGERANT PROPERTIES. THE REFRIGERATING EFFECT IS ALSO ALWAYS A LOWER VALUE THAN THE LATENT HEAT BECAUSE THE:

HEAT REQUIRED TO COOL THE REFRIGERANT FROM COMPRESSOR DISCHARGE TO EVAPORATIVE TEMPERATURE IS SUBTRACTED FROM LATENT HEAT

REFRIGERANT LATENT HEAT IS DIVIDED BY SPECIFIC GRAVITY OF THE REFRIGERANT

REFRIGERANT CRITICAL TEMPERATURE IS FACTORED INTO THE CALCULATION OF THE REFRIGERATING EFFECT

REFRIGERANT LATENT HEAT IS DIVIDED BY TH REFRIGERANT CIRCULATION RATE

A

HEAT REQUIRED TO COOL THE REFRIGERANT FROM COMPRESSOR DISCHARGE TO EVAPORATIVE TEMPERATURE IS SUBTRACTED FROM LATENT HEAT

87
Q

SHELL AND TUBE CONDENSERS HAVE THE ADVANTAGE OF:

REMOVING HEADS FOR CLEANING THE WATER SIDES OF THE TUBES

THE REFRIGERANT CONNECTIONS DOES NOT HAVE TO BE DISRUPTED

USING ACID FOR CLEANING

BOTH A AND B ARE CORRECT

A

BOTH A AND B ARE CORRECT

88
Q

WHEN A SYSTEM DOES NOT HAVE UNLOADERS, WHAT IS NEEDED?

OTHER CAPACITY CONTROL

VARIABLE INLET GUIDE VANES

AN ECONOMIZER

SOLENOID ON LIQUID LINE

A

OTHER CAPACITY CONTROL

89
Q

SHELL AND COIL CONDENSERS HAVE THE ADVANTAGE OF:

REMOVING HEADS FOR CLEANING THE WATER SIDES OF THE TUBES

THE REFRIGERANT CONNECTIONS DO NOT HAVE TO BE DISRUPTED

HAS LESS CHANCE OF DEVELOPING LEAKS

BOTH A AND B ARE CORRECT

A

HAS LESS CHANCE OF DEVELOPING LEAKS

90
Q

AN OPERATOR SUSPECTS THAT SHORTED MOTOR WINDINGS HAVE CAUSED THE MOTOR OVERLOADS TO TRIP. IN ORDER TO INVESTIGATE THIS CONDITION, THE OPERATOR WOULD BE MOST CORRECT TO USE

CAPACITOR

VOLTMETER

OHMMETER

AMMETER

A

OHMMETER

91
Q

HOW MANY BTUs WOULD BE REMOVED IN A 30 TON SYSTEM?

12,000 PER HOUR

360,000 PER MINUTE

12,000 PER MINUTE

360,000 PER HOUR

A

360,000 PER HOUR

A 30 ton system removes 12,000 BTU’s per minute

(Each ton = 400 btu’s per minute maybe)

92
Q

AN ELECTRIC MOTOR THAT IS RATED AT 3 HP WILL?

USE THREE PHASE

NEED A CAPACITOR

USE SINGLE PHASE

WILL RUN WITH REDUCED POWER OUTPUT

A

USE THREE PHASE

93
Q

COMPRESSOR MOTORS THAT OPERATE INSIDE THE REFRIGERANT ATMOSPHERE (ATMOSPHERIC):

MUST USE MATERIALS COMPATIBLE WITH THE SYSTEM REFRIGERANTS

MOTORS MUST BE ASSEMBLED IN CLEAN ATMOSPHERE AND KEEP DRY

ARE NOT WORKED ON IN THE FIELD

ALL THE ABOVE

A

ALL THE ABOVE

94
Q

WHILE USING A HALIDE TORCH TO CHECK FOR REFRIGERANT LEAKS, IF THE FLAME WAS TO TURN YELLOW, WHAT HAPPENED?

CONTAINER IS EMPTY

RESTRICTION IN TUBE

REFRIGERANT IS LEAKING

REFRIGERANT HAS HIGH MOISTURE CONTEN

A

RESTRICTION IN TUBE

95
Q

IF YOU HAVE 62 PSI AT 35°F AND 70 PSI AT 45°F, WHAT WOULD 38°F BE?

66

64.4

65

62

A

64.4

The given question is asking for the pressure at 38°F based on the given pressures at 35°F and 45°F. To find the pressure at 38°F, we can use the concept of linear interpolation. Since the temperature is increasing, we can assume that the pressure is also increasing linearly. By calculating the slope using the given data, we can determine the pressure at 38°F. The slope is (70 PSI - 62 PSI) / (45°F - 35°F) = 0.8 PSI/°F. Now, we can calculate the pressure at 38°F by using the formula: pressure at 38°F = 62 PSI + (0.8 PSI/°F) * (38°F - 35°F) = 64.4 PSI. Therefore, the correct answer is 64.4.
The given question is asking for the pressure at 38°F based on the given pressures at 35°F and 45°F. To find the pressure at 38°F, we can use the concept of linear interpolation. Since the temperature is increasing, we can assume that the pressure is also increasing linearly. By calculating the slope using the given data, we can determine the pressure at 38°F. The slope is (70 PSI - 62 PSI) / (45°F - 35°F) = 0.8 PSI/°F. Now, we can calculate the pressure at 38°F by using the formu

96
Q

IF YOU HAD 38°F IN THE EVAPORATOR, WHAT SHOULD YOUR SUCTION PRESSURE BE FOR R-22

66 PSIA

66 PSIG

76 PSIG

76 PSIA

A

66 PSIG

Feedback
The correct answer is 66 PSIG. In refrigeration systems, the evaporator temperature is directly related to the suction pressure. R-22 is a common refrigerant, and for a temperature of 38°F in the evaporator, the corresponding suction pressure should be 66 PSIG. The “PSIG” unit indicates that the pressure is measured in pounds per square inch gauge, which means it is measured relative to atmospheric pressure.
The correct answer is 66 PSIG. In refrigeration systems, the evaporator temperature is directly related to the suction pressure. R-22 is a common refrigerant, and for a temperature of 38°F in the evaporator, the corresponding suction pressure should be 66 PSIG. The “PSIG” unit indicates that the pressure is measured in p

97
Q

COPPER USED IN REFRIGERATION SYSTEMS, LIKE IN HEAT EXCHANGERS, BECAUSE?

EASY FABRICATION

EASY DURABILITY

HIGH THERMAL CONDUCTIVITY

FLEXIBILITY

A

HIGH THERMAL CONDUCTIVITY

Refrigerant Machine Operator Practical (5 decks)

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