Refrigerant Machine Operator License Exam Prep Test

121 Questions | Total Attempts: 721

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Refrigerant Machine Operator Quizzes & Trivia

Below is a quiz on the refrigerant machine operator! It is designed to help an operator review all that they know about fridges and how to correct any defaults they may be experiencing. How about you give it a shot and get to see if all you know is enough to provide you with the certification. All the best of luck!


Questions and Answers
  • 1. 
    IF THE ELIMINATOR PLATES LOCATED BELOW THE FAN IN AN INDUCED DRAFT-COOLING TOWER HAVE BECOME CLOGGED, OF THE FOLLOWING THIS WOULD MOST LIKELY RESULT IN: 
    • A. 

      DAMAGE TO FAN BLADES

    • B. 

      INCREASE IN COOLING TOWER WATER TEMP BEING RETURNED

    • C. 

      DECREASE IN MAKEUP WATER REQUIREMENTS

    • D. 

      A DROP IN WET BULB TEMP

  • 2. 
    CONVERT 18" VACUUM TO PSIA
    • A. 

      7.7

    • B. 

      0.6

    • C. 

      5.9

    • D. 

      23.5

  • 3. 
    SUPERHEATED VAPOR PROTECTS THE COMPRESSOR AGAINST LIQUID INTAKE.  WHAT WOULD THE RMO NOTICE IF COMPRESSOR WAS RECEIVING LIQUID?
    • A. 

      HEAD PSI DROPPING TO LOW

    • B. 

      DECREASE THE CAPACITY OF THE COMPRESSOR AND REFRIGERATION SYSTEM

    • C. 

      NON-CONDENSABLES ARE MORE PRONE TO COLLECT IN THE SYSTEM

    • D. 

      FROST MAY DEVELOP IN THE SUCTION LINE

  • 4. 
    WHAT REFRIGERANT SYSTEMS ARE MOST LIKELY TO LEAK REFRIGERANT IN BUILDING SPACES THAT ARE BEING COOLED?
    • A. 

      INDIRECT SYSTEMS

    • B. 

      DIRECT SYSTEMS

    • C. 

      INDIRECT CLOSED SYSTEMS

    • D. 

      INDRIECT OPEN SYSTEMS

  • 5. 
    AN OPERATOR HAS BEEN ASSIGNED TO A LARGE RECIPROCATING MACHINE WITHOUT UNLOADERS OF THE FOLLOWING SAFETY PROPER PROCEDURE FOR STARTING MACHINE IS. 
    • A. 

      FILTER SUCTION AND DISCHARGE VALVES

    • B. 

      SUCTION VALVE AND DISCHARGE BYPASS BOTH OPEN

    • C. 

      SUCTION BYPASS AND DISCHARGE VALVE BOTH OPEN

    • D. 

      DISCHARGE BYPASS AND SUCTION VALVE BOTH CLOSED

  • 6. 
    UPON BEING ASSIGNED TO A FACILITY DURING INSPECTION OF THE FACILITY, YOU FIND THERE HAS BEEN FAILURE TO MAINTAIN WATER TREATMENT.  INSPECTING THE CONDENSER WATER, THE FIRST EVIDENCE WOULD MOST LIKELY BE:
    • A. 

      DECREASE IN SUPER HEAT TEMP ENTERING COMPRESSOR

    • B. 

      AN INCREASE IN COMPRESSOR HEAD PRESSURE

    • C. 

      AN INCREASE IN THE FLOW RATE OF NONCONDENSABLES

    • D. 

      CONDENSER TO METERING DEVICE FROZEN

  • 7. 
    DURING A PARTICULAR ROUND AN OPERATOR NOTICES THAT THE SUCTION LINE AND PART OF THE COMPRESSOR ARE FROSTED, THE MOST LIKELY CAUSE OF THE CONDITION IS
    • A. 

      NOT ENOUGH REFRIGERANT IN SYSTEM

    • B. 

      EXPANSION VALVE OPEN TOO WIDE

    • C. 

      THE COMPRESSOR IS RUNNING CONTINUALLY

    • D. 

      COMPRESSOR VALVES ARE LEAKING

  • 8. 
    WHEN CHARGING AN R-12 RECIPROCATING REFRIGERATION SYSTEM, AN OPERATOR WOULD WANT TO USE WARM WATER TO INCREASE THE RELEASE RATE OF REFRIGERANT FROM THE DRUM.  TO PERFORM THIS OPERATION THE WATER TEMP. SHOULD NOT EXCEED THE DEGREE °F OF
    • A. 

      80°F

    • B. 

      90°F

    • C. 

      110°F

    • D. 

      130°F

  • 9. 
    WITH RESPECT TO FIRE SAFETY, THE ANSI/ASHRAE REFRIGERANT SAFETY CLASSIFICATION THAT IS MOST DANGEROUS IS
    • A. 

      A1

    • B. 

      B2

    • C. 

      A3

    • D. 

      B1

  • 10. 
    AT THE CONDENSER, REFRIGERANT ENTERS AS
    • A. 

      HIGH PRESSURE GAS AND LEAVES AS LOW PRESSURE LIQUID

    • B. 

      HIGH PRESSURE GAS AND LEAVES AS HIGH PRESSURE LIQUID

    • C. 

      SUPERHEATED GAS AND LEAVES AS HIGH TEMPERATURE LIQUID

    • D. 

      HIGH TEMPERATURE GAS AND LEAVES AS SUPERHEATED GAS

  • 11. 
    ACCORDING TO NYC FIRE CODE CLASSIFICATION OF REFRIGERANT, AMMONIA WOULD FALL UNDER WHICH GROUP?
    • A. 

      GROUP 1

    • B. 

      GROUP 2

    • C. 

      GROUP 3

    • D. 

      GROUP 4

  • 12. 
    IF AN ELECTRIC MOTOR IS REWOUND TO CUT RESISTANCE BY 1/2, ALL OTHER FACTORS BEING EQUAL, THE MOTOR POWER WOULD:
    • A. 

      REDUCE BY 1/2

    • B. 

      INCREASE BY A FACTOR OF 2

    • C. 

      STAY THE SAME

    • D. 

      INCREASE BY A FACTOR OF 4

  • 13. 
    ASSUME AN OPERATOR IS ABLE TO OBSERVE R-11, WATER AND LUBRICATING OIL TOGETHER AT 70°F.  UNDER THESE CONDITIONS, THE WATER, MOISTURE, AND FLUIDS WOULD SETTLE IN THE CONTAINER FROM TOP TO BOTTOM IN WHAT ORDER?
    • A. 

      WATER, OIL, REFRIGERANT

    • B. 

      OIL, REFRIGERANT, WATER

    • C. 

      REFRIGERANT, OIL, WATER

    • D. 

      OIL, WATER, REFRIGERANT

  • 14. 
    A RECIPROCATING REFRIGERATION COMPRESSOR CYLINDER HAS A 12" BORE AND 16" STROKE, THE VOLUME OF REFRIGERANT IN CUBIC INCHES WOULD BE CLOSER TO
    • A. 

      1204

    • B. 

      1002

    • C. 

      1808

    • D. 

      1406

  • 15. 
    YOU HAVE BEEN INFORMED THAT THE O.A.T. HAS DROPPED 10°C.  THE TEMPERATURE IN °F IS
    • A. 

      32

    • B. 

      28

    • C. 

      40

    • D. 

      18

  • 16. 
    AN AUTOMATIC PURGE UNIT IS REQUIRED FOR THOSE REFRIGERATING SYSTEMS THAT HAVE
    • A. 

      DOUBLE INDIRECT OPEN SPACE SYSTEMS

    • B. 

      SYSTEMS OPERATING BELOW ATMOSPHERIC PRESSURE

    • C. 

      ABSORPTION COMPRESSORS

    • D. 

      OUTSIDE AIR DAMPERS

  • 17. 
    ORIFICE PLATES MAY BE USED AS A METERING DEVICE COMPONENT IN A CENTRIFUGAL SYSTEM.  THE VESSEL WHICH THEY ARE CONTAINED IN CAN ALSO SERVE AS
    • A. 

      VAPOR RECYCLING UNIT

    • B. 

      AN ECONOMIZER

    • C. 

      REFRIGERANT CLEANER

    • D. 

      EVAPORATOR

  • 18. 
    A RUPTURE DISC IN A CENTRIFUGAL REFRIGERATING MACHINE IS NORMALLY LOCATED ON THE
    • A. 

      CONDENSER

    • B. 

      ECONOMIZER

    • C. 

      COMPRESSOR DISCHARGE

    • D. 

      EVAPORATOR

  • 19. 
    A PUMP AFFECTS THE PRESSURE OF A FLUID OR GAS BY: 
    • A. 

      REDUCING PRESSURE

    • B. 

      RAISING PRESSURE

    • C. 

      REGULATING PRESSURE

    • D. 

      STABILIZING PRESSURE

  • 20. 
    AN OPERATOR IS RUNNING TWO CENTRIFUGAL CONDENSER PUMPS IN PARALLEL, ONE OF THE PUMPS IS AT MAXIMUM PUMPING RATE, IF THE OPERATOR THROTTLES BACK ON THE DISCHARGE VALVE OF THE OTHER PUMP, THE MOST LIKELY EFFECT WOULD BE
    • A. 

      A REDUCTION ON BOTH THE WATER FLOW RATE AND PRESSURE INTO THE CONDENSER

    • B. 

      A REDUCTION IN TOTAL FLOW RATE TO CONDENSER

    • C. 

      A REDUCTION IN WATER PRESSURE AT THE CONDENSER INLET

    • D. 

      FOR THE PUMPS TO COMPENSATE TO MAINTAIN BOTH THE FLOW RATE AND DISCHARGE PRESSURE

  • 21. 
    AS AN RMO IN CHARGE, YOU ARE REQUESTED TO REPLACE THE GAUGE ON THE HIGH SIDE OF THE REFRIGERATION SYSTEM.  THE PRESSURE GRADUATION RATE SHOULD BE
    • A. 

      1.2 OF DESIGN PRESSURE (AT LEAST)

    • B. 

      THE RUPTURE GUARD HAS TO BE REPLACED ALSO

    • C. 

      THE GAUGE HAS TO BE A COMPOUND GAUGE

    • D. 

      THE GAUGE SHOULD BE GRADUATED TO PRESSURE

  • 22. 
    WHEN OPERATING A REFRIGERATION UNIT, THE OPERATOR NOTICES THAT THE MOTOR COMPRESSOR IS SHORT CYCLING, THE UNIT IS USING A LOW SIDE FLOAT VALVE.  THE FOLLOWING SERVICE REQUIREMENTS WOULD INDICATE
    • A. 

      INSPECTION SHOULD BE MADE FOR DIRTY TEV STRAINER

    • B. 

      PARTIALLY CLOGGED DISCHARGE LINE

    • C. 

      CHECK COMPRESSOR WIRING, FOR OVERLOADED EQUIPMENT

    • D. 

      ADDITIONAL REFRIGERANT BE CHARGED

  • 23. 
    OF THE FOLLOWING THE MOST CORRECT WAY TO DESCRIBE A BRAZED JOINT IS
    • A. 

      PRESSURE FITTING

    • B. 

      GAS TIGHT FITTING

    • C. 

      START TO MELT AT 400°F

    • D. 

      START TO MELT AT 500°F

  • 24. 
    YOU ARE AN RMO ASSIGNED TO THE 3RD FLOOR IN AN ASSEMBLY ROOM.  ATTENDANCE AND TEMP HAVE INCREASED DURING THE AFTERNOON, THEREFORE A COLDER WATER SUPPLY IS TO BE PRODUCED.  IN ORDER TO ACCOMPLISH THIS YOU SHOULD.
    • A. 

      RE-ADJUST THE TEV SUPERHEAT SETTING

    • B. 

      DEACTIVATE THE FREEZE STAT

    • C. 

      RAISE THE COMPRESSOR DISCHARGE OPERATING PRESSURE

    • D. 

      LOWER THE COMPRESSOR SUCTION OPERATING PRESSURE

  • 25. 
    OF THE FOLLOWING THE MOST UNDESIRABLE PROPERTY IN REFRIGERANT IS
    • A. 

      LOW CORRESPONDING COMPRESSOR DISCHARGE TEMP

    • B. 

      LOW VISCOSITY

    • C. 

      LOW LATENT HEAT

    • D. 

      LOW CORRESPONDING OPERATING PRESSURE

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