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Book 2 PanGlobal Assessment Test > Chapter 26 Compression Refrigeration System Operations > Flashcards

Chapter 26 Compression Refrigeration System Operations Flashcards

1
Q
  1. The benefits of a good preventative maintenance program may included all of the following except:
    A. Reduced spare parts inventory required
    B. Control of labour and material cost
    C. Better means of identifying causes of breakdowns
    D. Reduced life expectancy of plant and equipment
    E. Accumulation of history records for each piece of equipment
A

D. Reduced life expectancy of plant and equipment

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2
Q
  1. Most refrigeration systems are controlled by a motor demand limiter that limits the:
    A. Maximum refrigerant flow to the compressor
    B. Maximum water flow to the condenser
    C. Minimum current flow to the compressor motor
    D. Maximum current flow to the compressor motor
    E. Minimum refrigerant flow to the evaporator
A

D. Maximum current flow to the compressor motor

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3
Q
  1. The refrigerant low temperature cutout is a safety low limit thermostat that senses the:
    A. Water temperature in the chiller
    B. Refrigerant temperature in the condenser
    C. Refrigerant temperature in the chiller
    D. Water temperature in the evaporator
    E. Refrigerant pressure in the chiller
A

C. Refrigerant temperature in the chiller

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4
Q
  1. What is the symptom of a refrigeration system when the compressor discharge pressure is too low due to too much condenser water?
    A. Water temperature at outlet too low
    B. Lack of refrigerant
    C. Bubbles in sight glass
    D. Leaky relief bypass valve
    E. Low discharge pressure and high suction pressure
A

A. Water temperature at outlet too low

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5
Q 
5.	If the refrigeration compressor is equipped with an oil sump heater, ensure it is energized and that the oil temperature is high enough to drive off any:
A.	Air
B.	Carbon dioxide
C.	Refrigerant
D.	Oil
E.	Water
A

C. Refrigerant

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6
Q
  1. What is the symptom of a refrigeration system when the compressor short-cycles” due to the low pressure controller differential set too close?

A. Compressor operates normally but starts and stops frequently
B. Reduced air flow due to broken fan belt
C. Leaky liquid line solenoid valve
D. Reduced air flow due to dirty air filters
E. Intermittent contact in electrical circuit

A

A. Compressor operates normally but starts and stops frequently

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7
Q 
7.	What is the symptom of a refrigeration system when the compressor suction pressure is too low due an obstructed  expansion valve?
A.	Lack of refrigerant
B.	Evaporator dirty or iced up
C.	Loss of capacity
D.	Compressor short-cycles
E.	Conditioned space too cold
A

C. Loss of capacity

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8
Q
  1. The information card that code requires for refrigeration systems over 125 kW must include all of the following information except:
    A. Instructions for shutting down the system in case of emergency
    B. Instructions for starting up the system in case of emergency
    C. The name, address and day and night telephone numbers for obtaining service
    D. The name, address, and telephone number of the regulatory authority
    E. Instructions to notify said authority immediately in case of emergency
A

B. Instructions for starting up the system in case of emergency

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9
Q 
9.	The vane closed switch is in the motor starting circuit so that the compressor can only be started when the vanes are in the \_\_\_\_\_ position.
A.	Evaporator open
B.	Compressor closed
C.	Compressor open
D.	Evaporator closed
E.	Closed position
A

E. Closed position

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10
Q 
10.	The low oil pressure cutout switch is a safety shutdown device that prevents compressor operation when oil pressure is:
A.	Below a safe minimum value
B.	Too low in the crankcase
C.	Too cold
D.	Too high
E.	Below the refrigerant level
A

A. Below a safe minimum value

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11
Q
  1. Why must you avoid running a refrigeration system below 14 KPa when pumping down?
    A. A slightly positive system pressure is required to prevent air infiltration
    B. Too much refrigerant will be required for a recharge
    C. The compressor will need to be stopped to prevent it running dry
    D. The systems heat exchangers will ice up
    E. The heat exchanges may collapse due to the low pressure
A

A. A slightly positive system pressure is required to prevent air infiltration

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12
Q
  1. On larger capacity refrigeration compressors the _____ valves prior to starting.
    A. Open the suction and discharge
    B. Close the suction and open the discharge
    C. Open the suction and close the discharge
    D. Close the suction and discharge
    E. Open the bypass
A

B. Close the suction and open the discharge

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13
Q
  1. On smaller capacity refrigeration compressors the _____ valves prior to starting.
    A. Open the suction and discharge
    B. Close the suction and discharge
    C. Open the suction and close the discharge
    D. Close the suction and open the discharge
    E. Open the bypass
A

A. Open the suction and discharge

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14
Q
  1. What is the purpose of the chilled water flow switch?
    A. Starts the compressor on a low refrigerant flow condition
    B. Opens the vanes so that the compressor can be restarted under load
    C. Starts the chilled water booster pump
    D. Protects the chiller from freezing due to lack of water flow
    E. It confirms refrigerant flow to the evaporator
A

D. Protects the chiller from freezing due to lack of water flow

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15
Q
  1. What is the symptom of a refrigeration system when the compressor runs continuously due to a lack of refrigerant?
    A. Excessive load
    B. Bubbles in the sight glass
    C. High discharge pressure
    D. Low temperature of substance to be cooled
    E. Thermostat set too low
A

B. Bubbles in the sight glass

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16
Q 
16.	What is the symptom of a refrigeration system that has high suction pressure due to an oversized expansion valve?
A.	Non-condensables in the system
B.	An abnormally cold suction line
C.	Fouled condenser
D.	Contaminants in the refrigerant
E.	Undersized compressor
A

B. An abnormally cold suction line

17
Q
  1. A clause in a code of the authority having jurisdiction states “It shall be the duty of the person in charge of the premises on which a refrigerating system with prime mover(s) having a capacity in excess of _____ is installed to place conspicuously and as near as practicable to the refrigerant compressor a card giving directions for the operation of the system, including precautions to be observed in case of breakdown or leak as follows:
A.	125 kW
B.	100 kW
C.	25 kW
D.	250 kW
E.	500 kW
A

A. 125 kW

18
Q 
18.	The purging unit of the refrigeration system should be operated for at least \_\_\_\_\_ minutes before the compressor is started (time depends on the size of the system). 
A.	15
B.	10
C.	5
D.	25
E.	20
A

B. 10

Book 2 PanGlobal Assessment Test (40 decks)

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