Book 2: 5-24 - "Refrigeration Cycle Controls"

Question 1

A pressure-actuated refrigeration control cannot be used in conjunction with a/an _____ expansion valve
Select one:

A. Thermostatic

B. Solenoid

C. Automatic

D. Hand

E. Humidity

Answer 1

C. Automatic

Question 2

In the event of a low oil pressure condition, the oil pressure failure switch will:
Select one:

A. Sound an audible alarm

B. Open the recycle valve to take the load off the compressor

C. Stop the flow of refrigerant to the system

D. Shutdown the compressor

E. Stop the air circulation fan

Answer 2

D. Shutdown the compressor

Question 3

The thermostatic refrigeration controller has a range adjustment that sets the temperature level at which the:
Select one:

A. Fan starts and stops

B. Condenser cooling water control activates

C. Level in the evaporator control activates

D. Cut-in and cut-out occurs

E. Expansion valve opens and closes

Answer 3

D. Cut-in and cut-out occurs

Question 4

Motor overload protection is a manual reset device that will take the motor itself offline when the current drawn by the motor exceeds:
Select one:

A. Its minimum allowable value

B. The condenser maximum allowable pressure

C. The evaporator maximum allowable temperature

D. Its maximum allowable oil temperature

E. Its maximum allowable value

Answer 4

E. Its maximum allowable value

Question 5

The high-pressure safety cutout protects the refrigerating system from higher than normal pressures due to the:
Select one:

A. Presence of refrigerants in the system

B. Presence of non-condensables in evaporator

C. High compressor oil pressure

D. Loss of refrigerant

E. Presence of non-condensables in the system

Answer 5

E. Presence of non-condensables in the system

Question 6

Flow switches are used on chilled water and cooling water lines and air ducts are used as _____ switches.
Select one:

A. Evaporator level control

B. Safety lockout

C. Low temperature lockout

D. Over pressure lockout

E. Condenser pressure control

Answer 6

B. Safety lockout

Question 7

The condenser automatic cooling water regulating valve is operated by the:
Select one:

A. Liquid pressure on the compressor suction

B. Vapour pressure on the compressor suction

C. Vapour pressure on the evaporator discharge

D. Liquid pressure on the compressor discharge

E. Vapour pressure on the compressor discharge

Answer 7

E. Vapour pressure on the compressor discharge

Question 8

One of the three distinct classes of refrigeration controls is the _____ control.
Select one:

A. Solenoid

B. Cooling water regulating

C. Limiting and safety

D. Condenser fan

E. Humidity actuated

Answer 8

C. Limiting and safety

Question 9

The sensing device of a humidistat may consist of a/an _____ element.
Select one:

A. Pneumatic

B. Hydrophobic

C. Hydroponic

D. Hydroscopic

E. Hygroscopic

Answer 9

E. Hygroscopic

Question 10

The operation of the compressor (starting, stopping, and unloading) may be accomplished by a _____ type of actuated control.
Select one:

A. Temperature

B. Volume Humidity

C. Mass

D. Density

E. Level

Answer 10

A. Temperature

Question 11

The thermostatic refrigeration controller has a differential adjustment that sets the temperature at which the:
Select one:

A. Level in the evaporator control activates

B. Condenser cooling water control activates

C. Cut-in and cut-out occurs

D. Fan starts and stops

E. Expansion valve opens and closes

Answer 11

C. Cut-in and cut-out occurs

Question 12

The CSA B52 Mechanical Refrigeration Code requires that the pressure limiting device be designed to stop the action of the compressor or generator at a pressure not more than _____ of the system high side design pressure.
Select one:

A. 80%

B. 100%

C. 70%

D. 90%

E. 60%

Answer 12

D. 90%

Question 13

The operation of the compressor (starting, stopping, and unloading) may be accomplished by a _____ type of actuated control.
Select one:

A. Density

B. Volume Humidity

C. Level

D. Pressure

E. Mass

Answer 13

D. Pressure

Question 14

The thermostatic refrigeration controller produces mechanical when subjected to _____ fluctuations in the cooled medium.
Select one:

A. Humidity

B. Electrical

C. Pressure

D. Electronic

E. Temperature

Answer 14

E. Temperature

Question 15

The high oil temperature cutout is a safety control that shuts down the compressor when the lubricating oil temperature becomes too high due to:
Select one:

A. Loss of refrigerant

B. Condenser high pressure

C. Evaporator high temperature

D. Loss of oil cooling

E. Condenser high temperature

Answer 15

D. Loss of oil cooling

Question 16

With the direct type of temperature-actuated refrigeration control the thermostat is located directly in the:
Select one:

A. Receiver

B. Refrigerator

C. Space to be cooled

D. Condenser

E. Evaporator

Answer 16

C. Space to be cooled

Question 17

The solenoid valve is operated by a/an _____ signal.
Select one:

A. Electronic

B. Temperature

C. Humidity

D. Electrical

E. Pressure

Answer 17

D. Electrical

Question 18

The operation of the compressor (starting, stopping, and unloading) is usually accomplished by a _____ type of actuated control.
Select one:

A. Volume

B. Temperature

C. Density

D. Level

E. Mass

Answer 18

B. Temperature

Question 19

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:
Select one:

A. Low limit thermostat

B. High-pressure safety cutout

C. High oil temperature cutout

D. Condenser cooling water regulating valve

E. Operating controls

Answer 19

E. Operating controls

Question 20

One of the most important secondary controls in a refrigerating system is the refrigerant flow control used to regulate the amount of liquid refrigerant flowing into the:
Select one:

A. Receiver

B. Evaporator

C. Refrigerator

D. Condenser

E. Refrigerated space

Answer 20

B. Evaporator