Refrigerant Machine Operator Practice Test #2 Flashcards by Christine Banker

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

Yellow tops

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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

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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

RECEIVER, DRIER, SOLENOID VALVE, AND SIGHT-GLASS

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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

NOT BE USED FOR REFRIGERATION

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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

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

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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

565 CUBIC FEET

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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

BOTH UNDER AND OVER VALVE PLATE

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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

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

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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

STARTING UP AN ADDITIONAL PUMP

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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

4227

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

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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

140

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

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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

INCREASES

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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

OXYGEN DEPRIVATION

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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

SUPERHEATED VAPOR AND WARM SUB-COOLED LIQUID

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thing is used for ____

recovery

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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

ACCOMPLISH LOWER TEMPERATURE

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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

15-30 PSI HIGHER

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CLEARANCE VOLUME:

AFFECTS COMPRESSOR CAPACITY

IS THE SPACE THAT TRAPS LIQUID REFRIGERANT

VARIES, DEPENDING ON COMPRESSOR SPEED

IS THE SAME ON ALL COMRPESSORS

AFFECTS COMPRESSOR CAPACITY

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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

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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

DRY BULB HIGHER THAN WET BULB

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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

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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

LOW PRESSURE CUT OUT

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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

USE MATERIALS TAILORED TO THE REFRIGERANT

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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

LOW PRESSURE CUT OUT

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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 DISTRIBUTOR

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

EXCESSIVE SUPERHEAT

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

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

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

HIGH SIDE PRESSURE

A REFRIGERATION UNIT IS MEASURED IN: WATTS VOLTS BTUs TEMPERATURE

BTUS

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

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

WHAT IS 29.92" HG IN KPA 101.3 101.28 101.26 103.2

101.3 1 HG” = 3.386

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

TO PREVENT OIL SLUGGING IN THE COMPRESSOR

THE MECHANISM SITTING ABOVE THE EVAPORATOR IS KNOWN AS ECONOMIZER PURGE UNIT AIR BLEED PRESSURE RELIEF VALVE

PURGE UNIT

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

SUPERHEATED VAPOR

THE RUPTURE DISK IS ALWAYS PIPED INTO THE HIGH SIDE LOW SIDE EITHER SIDE OF SYSTEM NEITHER SIDE SYSTEM

LOW SIDE

WHEN DRY BULB IS 75°F AND WET BULB IS 75°F: NOT POSSIBLE VERY LOW HUMIDITY THERMOMETER IS DEFECTIVE 100% RELATIVE HUMIDITY

100% RELATIVE HUMIDITY

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

END OF COIL

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

CONDENSER OPERATION, DIRTY TUBES OR COOLING WATER CONTROL

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

GATE VALVES CAUSES MORE LEAKAGE

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

COMPRESSOR HAS PRESSURE RELIEF VALVE

COMPOUND GAUGES CAN MEASURE: ABOVE ATMOSPHERIC BELOW ATMOSPHERIC TEMPERATURE ALL OF THE ABOVE

ALL OF THE ABOVE

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

REFRIGERANT RECYCLING

WHAT REFRIGERANTS ARE YOU NOT ABLE TO DUMP? CFC HCFC HFC ANY REFRIGERANT CONTAINING CHLORINE OR FLUORINE

ANY REFRIGERANT CONTAINING CHLORINE OR FLUORINE

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

REPLACE ALL 4 BELTS WITH A NEW SET

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

MALFUNCTIONING OF THE WATER MAKE UP FLOAT VALVE

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

30.3 1 psi = 2.036 hg”

ACCORDING TO THE NYC FIRE CODE CLASSIFICATION OF REFRIGERANTS, AMMONIA AND SULPHER DIOXIDE AR GROUPED INTO: GROUP 2 GROUP 4 GROUP 1 GROUP 3

GROUP 2

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

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

WHAT IS THE MAXIMUM PERCENTAGE THAT A REFRIGERANT CAN BE STORED IN An EPA CYLINDER? 80% 70% 90% 100%

80%

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

RECOVER ALL VAPOR, THEN DO WORK

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

COMPRESSOR AND EVAPORATIVE CONDENSER

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

HIGH HEAD PRESSURE

WHAT SHAFT SEAL PREVENTS VAPOR FROM LEAKING OUT OF COMPRESSOR? STUFFING BOX ELECTRO-MECHANICAL SEAL MECHANICAL SEAL ALL OF THE ABOVE

STUFFING BOX

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

EVAPORATOR WOULD STARVE

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

ALL OF THE ABOVE

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

RELATIVE HUMIDITY

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

PLACE THERMOMETER IN CUP OF ICE

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

ODORLESS WHEN MIXED WITH AIR

REGARDING FIRE SAFETY ANSI/ASHRAE, WHICH CLASSIFICATION INDICATES THE LEAST FLAMMABILITY AND LEAST TOXICITY? A1 B2 A2 B1

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

CONTROL THE AMOUNT OF REFRIGERANT IN CONDENSER

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

COMPRESSOR OUTLET AND THE ORIFICE OF THE METERING DEVICE

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

WATER VALVE STUCK OPEN

A FUSIBLE PLUG MELTS AT 450°F 280°F 212°F 800°F

280°F

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

SUDDEN DROP IN CRANKCASE PRESSURE

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

IT WILL CONTROL REFRIGERANT FLOW

WHEN CHARGING A CENTRIFUGAL SYSTEM THE POSITION OF THE VALVE IS: FRONT SEATED BACK SEATED CRACKED OFF THE BACK SEAT CLOSED

BACK SEATED

WHAT DOES CENTRIFUGAL COMPRESSOR GENERATE INSIDE? HIGH PRESSURE, LOW VOLOCITY HIGH VOLUME, LOW PRESSURE LOW VELOCITY, LOW PRESSURE HIGH VELOCITY, HIGH PRESSURE

HIGH VOLUME, LOW PRESSURE

THE HEAT THAT BOILS OFF IN A CONDENSER IS: LATENT HEAT SENSIBLE HEAT SUPERHEAT ALL OF THE ABOVE

LATENT HEAT

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

PARTIALLY PLUGGED FILTER/DRIER

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

STEP DOWN TRANSFORMER

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

FAULTY COOLING TOWER WATER LEVEL CONTROLLER

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

HIGHER THAN THE HEAT OF COMPRESSION

HOW LOW CAN CHILLER WATER TEMPERATURE BE? 32°F 33°F 38°F 42°F

33°F

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

OPEN SUCTION AND THROTTLE DISCHARGE

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

HIGH CONDENSER TEMPERATURE, LOW CONDENSER WATER TEMPERATURE

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

CLOGGED STRAINER IN PUMP INLET

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

ALL VALVE AND VALVE SEATS

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

FAULTY COMPRESSOR VALVES

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

ASSIST WITH COMPRESSOR START UP

THE CONDENSER THAT USES AIR AND WATER FOR COOLING IS THE: AIR COOLED WATER COOLED EVAPORATIVE BOTH A AND B ARE CORRECT

EVAPORATIVE

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

INCREASE WITH THE VELOCITY OF THE WATER IN THE TUBES

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

REQUIRES A HIGHER CHARGE

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

COMPRESSOR WOULD OPERATE AT HIGHER TEMPERATURE

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

RESTRICT FLOW OF REFRIGERANT FROM THE HIGH SIDE TO LOW SIDE

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

RESISTORS

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

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

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

BOTH A AND B ARE CORRECT

WHEN A SYSTEM DOES NOT HAVE UNLOADERS, WHAT IS NEEDED? OTHER CAPACITY CONTROL VARIABLE INLET GUIDE VANES AN ECONOMIZER SOLENOID ON LIQUID LINE

OTHER CAPACITY CONTROL

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

HAS LESS CHANCE OF DEVELOPING LEAKS

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

OHMMETER

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

360,000 PER HOUR A 30 ton system removes 12,000 BTU's per minute (Each ton = 400 btu's per minute maybe)

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

USE THREE PHASE

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

ALL THE ABOVE

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

RESTRICTION IN TUBE

IF YOU HAVE 62 PSI AT 35°F AND 70 PSI AT 45°F, WHAT WOULD 38°F BE? 66 64.4 65 62

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

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

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

COPPER USED IN REFRIGERATION SYSTEMS, LIKE IN HEAT EXCHANGERS, BECAUSE? EASY FABRICATION EASY DURABILITY HIGH THERMAL CONDUCTIVITY FLEXIBILITY

HIGH THERMAL CONDUCTIVITY

Refrigerant Machine Operator Practice Test #2 Flashcards

(97 cards)