Book 2 Unit 5

Question 1

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

Answer 1

D) Open the suction and discharge

Question 2

The high-pressure float valve is a liquid level operated control valve located on the:
A) Evaporator
B) High-pressure side of the system
C) Low-pressure side of the system
D) Downstream side of the evaporator
E) Downstream side of the expansion valve

Answer 2

B) High-pressure side of the system

Question 3

Positive pressure testing of a refrigeration system is done using dry __________ gas as the pressure agent.
A) Carbon monoxide
B) Helium
C) Nitrogen
D) Hydrogen sulphide
E) Oxygen

Answer 3

C) Nitrogen

Question 4

A pressure-actuated refrigeration control cannot be used in conjunction with a/an __________ expansion valve.
A) Solenoid
B) Humidity
C) Hand
D) Thermostatic
E) Automatic

Answer 4

E) Automatic

Question 5

Flow switches are used on chilled water and cooling water lines and air ducts are used as __________ switches.
A) Safety lockout
B) Low temperature lockout
C) Over pressure lockout
D) Evaporator level control
E) Condenser pressure control

Answer 5

A) Safety lockout

Question 6

The thermostatic refrigeration controller has a differential adjustment that sets the temperature at which the:
A) Cut-in and cut-out occurs
B) Condenser cooling water control activates
C) Expansion valve opens and closes
D) Level in the evaporator control activates
E) Fan starts and stops

Answer 6

A) Cut-in and cut-out occurs

Question 7

The most common application of evaporator capacity control is to use:
A) Adjustable evaporators
B) Sectional condensers
C) Sectional evaporators
D) Variable evaporators
E) Sectional receivers

Answer 7

C) Sectional evaporators

Question 8

What is the symptom of a refrigeration system when the compressor fails to start due to an open control circuit?
A) Seized compressor
B) Circuit breaker closed
C) Power on motor terminals
D) Full line voltage at terminals
E) No power on terminals of starter holding coil

Answer 8

E) No power on terminals of starter holding coil

Question 9

One of the safety devices on a centrifugal refrigeration compressor that acts preventing the compressor from being started is the ____________ switch.
A) Refrigerant level high
B) Refrigerant level low
C) Vane closed
D) Evaporator temperature high
E) Condenser temperature low

Answer 9

C) Vane closed

Question 10

If any moisture or water vapour is present in a refrigerating system that contains chlorine or fluorine an acid is formed that reacts with the compressor oil to produce sludge that will:
A) Coat the evaporator
B) Plug the expansion valve
C) Restrict cooling water flow
D) Corrode metal parts
E) Clog the condenser

Answer 10

D) Corrode metal parts

Question 11

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) 20
B) 10
C) 15
D) 5
E) 25

Answer 11

B) 10

Question 12

One of the disadvantages of evaporator capacity control by face damper is that the:
A) Refrigerant volume to the space is reduced
B) Refrigerant pressure to the space is reduced
C) Temperature of the space is increased
D) Temperature of the space is reduced
E) Air volume to the space is reduced

Answer 12

E) Air volume to the space is reduced

Question 13

The most widely used refrigerant control is the:
A) Capillary tube
B) Automatic expansion valve
C) Hand operated expansion valve
D) Low pressure float
E) Thermostatic expansion valve

Answer 13

E) Thermostatic expansion valve

Question 14

The benefits of a good preventative maintenance program may include all of the following except:
A) Increased operating efficiency and a reduction in energy consumption
B) Reduction of overall maintenance costs
C) More dependable service from the equipment
D) Efficient scheduling of maintenance operations
E) Increase in major breakdown repairs

Answer 14

E) Increase in major breakdown repairs

Question 15

It may be illegal to ____________ a refrigeration system without determining the location of and repairing the system leak.
A) Simply add refrigerant to
B) Drain refrigerant from
C) Change the compressor of
D) Evacuate the evaporator of
E) Flush the condenser of

Answer 15

A) Simply add refrigerant to

Question 16

One design of a refrigeration compressor cylinder Unloader works by keeping:
A) The intake valves in the open position
B) Both intake and exhaust valves in the open position
C) The exhaust valves in the closed position
D) The exhaust valves in the open position
E) The exhaust valves in the closed position

Answer 16

D) The exhaust valves in the open position

Question 17

Refrigeration system log sheets can be obtained from all of the following except:
A) Inspection companies
B) Government agencies
C) Insurance companies
D) Refrigeration system manufacturers
E) Developed by the refrigeration system operator

Answer 17

B) Government agencies

Question 18

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) 500 kW
B) 25 kW
C) 100 kW
D) 125 kW
E) 250 kW

Answer 18

D) 125 kW

Question 19

Ammonia leaks in refrigeration systems can also be detected by using a sulphur candle which, when lit, gives off a cloud of __________ smoke when exposed to ammonia fumes or vapour.
A) Reddish hue
B) Bright green
C) Orange
D) White
E) Light blue

Answer 19

D) White

Question 20

The high motor temperature cutout stops the compressor if there is a loss of motor cooling or a motor overload due to malfunction of the:
A) High oil temperature cutout
B) Operating controls
C) Low limit thermostat
D) Condenser cooling water regulating valve
E) High-pressure safety cutout

Answer 20

B) Operating controls