Refrigerant Machine Operator Practice Test #2 Flashcards
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
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
BOTH A AND B ARE CORRECT
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
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
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
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
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
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
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
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)
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
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
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
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
thing is used for ____
recovery
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
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
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
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
ALL OF THE ABOVE
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
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
FLOODED EVAPORATOR
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
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
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
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
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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
A1
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
