Refrigerant Machine Operator Certification Practice Test

100 Questions | Total Attempts: 17173

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Refrigerant Machine Operator Certification Practice Test

Industrial refrigerant machine operators seem to be simple people within the production chain but essentially are very important. Take up the quiz below and see how good you are as a refrigerant machine operator. This test consists of 100 most important questions that will help you clear the certification exam of the same. All the best.


Questions and Answers
  • 1. 
    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

  • 2. 
    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

  • 3. 
    YOU ARE AN RMO ASSIGNED TO FACILITY WHERE A REFRIGERANT HAS BEEN RECENTLY CHANGED FROM A FLAMMABLE REFRIGERANT TO R-22, AT THE MOMENT YOU ARE PLANNING TO BRAZE METAL.  ON SUCH MAKING A REPAIR IN THE MACHINERY ROOM, UNDER THESE CIRCUMSTANCES YOU:
    • A. 

      MUST ENSURE THE FLAME IS ENCLOSED AND VENTED TO OPEN AIR

    • B. 

      MAY MAKE REPAIRS AT LEAST 25 FEET FROM THE REFRIGERANT UNIT

    • C. 

      MAY MAKE REPAIRS WITHOUT ANY RESTRICTIONS IF THE REFRIGERATING UNIT IS SHUT DOWN

    • D. 

      MAY NOT MAKE REPAIR UNDER ANY CIRCUMSTANCES

  • 4. 
    WITH RESPECT TO FIRE SAFETY, THE ANSI/ASHRAE REFRIGERANT SAFETY CLASSIFICATION THAT IS MOST DANGEROUS IS
    • A. 

      A1

    • B. 

      B2

    • C. 

      A3

    • D. 

      B1

  • 5. 
    WHY SHOULD YOU CHARGE WITH VAPOR?
    • A. 

      YOU COULD BREAK THE RUPTURE GUARD WITH LIQUID

    • B. 

      YOU CAN ENTRAIN THE OIL IN THE REFRIGERANT WITH LIQUID

    • C. 

      YOU CAN FREEZE WATER IN THE TUBES WITH LIQUID

    • D. 

      YOU CAN OVER CHARGE THE SYSTEM WITH LIQUID

  • 6. 
    WHY IS SPRING LOADED PRV BETTER TO USE THAN A FUSIBLE PLUG?
    • A. 

      LESS EXPENSIVE

    • B. 

      EASY AVAILABILITY

    • C. 

      FUSIBLE PLUG CANNOT RESET

    • D. 

      LARGER

  • 7. 
    WHILE MONITORING THE OPERATION OF A RECIPROCATING REFRIGERATING UNIT YOU OVERSEE THAT THE CYCLING TIMES ARE NORMAL, COMPRESSOR COMPRESSION AND TEMP ARE THE ONLY READING THAT ARE OUTSIDE THE NORMAL RATE. UNDER THESE CONDITIONS SERVICE REQUIREMENTS WOULD INDICATE INSPECTING FOR
    • A. 

      FAULTY MACHINE CONTROL

    • B. 

      PROPER REFRIGERATION CHARGE

    • C. 

      FAULTY COMPRESSOR VALVES

    • D. 

      POOR CONDENSER OPERATION / DIRTY TUBES

  • 8. 
    WHICH TYPE OF PUMP IS CONSIDERED A NON-POSITIVE DISPLACEMENT PUMP?
    • A. 

      RECIPROCATING

    • B. 

      ROTORY, SCREW

    • C. 

      SCROLL

    • D. 

      CENTRIFUGAL

  • 9. 
    WHICH OF THE FOLLOWING ASHRAE SAFETY GROUPS IS THE MOST DANGEROUS?
    • A. 

      A1

    • B. 

      A2

    • C. 

      B2

    • D. 

      B3

  • 10. 
    WHICH IS NOT USED AS A COOLING MEDIUM IN AN INDIRECT SYSTEM
    • A. 

      R-22

    • B. 

      CALCIUM CHLORIDE

    • C. 

      GLOCOL

    • D. 

      SODIUM CHLORIDE

  • 11. 
    WHEN PROPERLY PURGING YOU SHOULD
    • A. 

      PURGE AT RAPID RATE

    • B. 

      PURGE WITH COMPRESSOR ON

    • C. 

      STOP WHEN PRESSURE CEASES TO DROP

    • D. 

      RUN THE CONDENSER AS MUCH AS POSSIBLE

  • 12. 
    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

  • 13. 
    WHEN OPERATING A REFRIGERATION MACHINE CONDENSER USING R-22 REFRIGERANT, UNDER NORMAL CONDITIONS THE OPERATOR OBSERVES THAT THE COOLING WATER IS BEING SUPPLIED AT 85°F AND LEAVING AT 95°F.  GIVEN THIS INFORMATION, THE CORRESPONDING COMPRESSOR HEAD PRESSURE IN PSI SHOULD BE MOST NEARLY:
    • A. 

      113

    • B. 

      313

    • C. 

      213

    • D. 

      13

  • 14. 
    WHEN INSTALLING A SERVICE VALVE TO ISOLATE A DUAL PRESSURE DEVICE WHILE KEEPING SYSTEM IN SERVICE, YOU WOULD USE A 
    • A. 

      TWO WAY VALVE

    • B. 

      THREE WAY VALVE

    • C. 

      PLUG VALVE

    • D. 

      STOP VALVE

  • 15. 
    WHEN INSTALLING A PIPELINE AND YOU NEED TO MAKE A 90° ELBOW, WHICH IS THE BEST WAY?
    • A. 

      BEND PIPE

    • B. 

      USE FACTORY MADE 90° ELBOW AND BRAZE

    • C. 

      USE FLEXIBLE TUBING

    • D. 

      USE TWO 45° ELBOWS

  • 16. 
    WHEN CONDUCTING A ROUTINE TOUR OF PLANT OPERATION A RMO OBSERVES A SIGNIFICANT INCREASE IN SUPERHEAT TEMP.  FOR THE REFRIGERATING FLUID ENTERING A RECIPROCATING COMPRESSOR.  OF THE FOLLOWING THE MOST LIKELY CAUSE FOR THIS CONDITION IS
    • A. 

      SCALE PARTICLES LODGED IN THE TEV VALVE

    • B. 

      UNRAVELING OF THE INSULATION PROTECTING THE TEV VALVE THERMAL BULB

    • C. 

      BUILD-UP OF NONCONDENSABLES IN THE CONDENSER

    • D. 

      OVERCHARGE OF REFRIGERANT

  • 17. 
    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

  • 18. 
    WHEN CHARGING A SYSTEM WITH LIQUID REFRIGERANT WITH A SET OF MANIFOLD GAUGES, WHAT POSITION ARE THE VALVES ON THE MANIFOLD?
    • A. 

      HIGH AND LOW VALVES BACKSEATED

    • B. 

      HIGH AND LOW VALVES FRONTSEATED

    • C. 

      HIGH SIDE BACKSEATED, LOW SIDE FRONTSEATED

    • D. 

      HIGH SIDE FRONTSEATED, LOW SIDE BACKSEATED

  • 19. 
    WHEN CHANGING WATER TO ICE, WHAT MUST BE REMOVED?
    • A. 

      SPECIFIC HEAT

    • B. 

      SUPER HEAT

    • C. 

      LATENT HEAT

    • D. 

      SENSIBLE HEAT

  • 20. 
    WHAT WOULD HAPPEN IF THE SPRING IN THE TEV WERE TO BREAK?
    • A. 

      FLOOD THE EVAPORATOR

    • B. 

      STARVE THE EVAPORATOR

    • C. 

      NO CHANGE

    • D. 

      DAMAGE FEELER BULB

  • 21. 
    WHAT SAFETY GROUP DOES AMMONIA BELONG?
    • A. 

      GROUP 2, B2

    • B. 

      GROUP 1, A1

    • C. 

      GROUP 3, B1

    • D. 

      BOTH A1 AND B1

  • 22. 
    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

  • 23. 
    WHAT IS THE TEV DIAPHRAM MADE OF
    • A. 

      RUBBER

    • B. 

      METAL

    • C. 

      PLASTIC

    • D. 

      GRAPHITE

  • 24. 
    WHAT IS THE PURPOSE OF THE EQUALIZER LINE?
    • A. 

      TO EQUALIZE PRESSURE IN THE TEV ALONG THE DIAPHRAM AND BELLOWS

    • B. 

      TO MAKE UP FOR THE PRESSURE DROP IN EVAPORATOR

    • C. 

      TO METER REFRIGERANT

    • D. 

      TO REMOVE PRESSURE DROP

  • 25. 
    WHAT IS THE DISADVANTAGE OF HAVING A LOW HEAD PRESSURE?
    • A. 

      EVAPORATOR WOULD FLOOD

    • B. 

      COMPRESSOR WOULD HUNT

    • C. 

      EXPANSION VALVE WOULD NOT FEED PROPERLY

    • D. 

      CONDENSER COULD NOT SUB-COOL