Book 2: 5-25 - "Compression Refrigeration System Pre-Startup Procedures"

Question 1

Just before charging an empty refrigerating system, the entire system should be:
Select one:

A. Hydro tested

B. Pressure tested

C. Boiled out

D. Pressures to the maximum allowable working pressure

E. Put under a very high vacuum

Answer 1

E. Put under a very high vacuum

Question 2

Non-condensable gases in a refrigeration system consist mainly of _____ that may have leaked into the system by improper operating or maintenance procedures.
Select one:

A. Gases caused by lubrication breakdown

B. Sulphur dioxide

C. Air

D. Impurities in the refrigerant

E. Nitrogen oxide

Answer 2

C. Air

Question 3

Evacuation of the refrigeration system should not be attempted unless the temperature of the surrounding air is _____ or higher.
Select one:

A. 0°C (32°F)

B. 10°C (50°F)

C. 20°C (68°F)

D. 15°C (59°F)

E. 5°C (41°F)

Answer 3

C. 20°C (68°F)

Question 4

Once any leaks found in the system are repaired:
Select one:

A. Refrigerant can be added to the system

B. The system should be evacuated

C. The system is ready for operation

D. The pressure can be released

E. A second pressure test should be conducted

Answer 4

E. A second pressure test should be conducted

Question 5

The initial refrigerant charge is given on the _____ side of the system.
Select one:

A. Expansion valve outlet

B. Low-pressure

C. Compressor inlet

D. Evaporator

E. High-pressure

Answer 5

E. High-pressure

Question 6

As the pressurizing gas is admitted to the refrigeration system the pressure is first increased to the required:
Select one:

A. High-pressure side maximum design pressure

B. High-pressure side minimum design pressure

C. Low-pressure side minimum design pressure

D. High-pressure side operating pressure

E. Low-pressure side operating pressure

Answer 6

C. Low-pressure side minimum design pressure

Question 7

Frost formation on the suction line in a _____ system may indicate overcharging.
Select one:

A. Automatic expansion

B. High-pressure float

C. Capillary tube

D. Thermostatic expansion

E. Low-pressure float

Answer 7

C. Capillary tube

Question 8

It is the _____ part of the refrigerant molecular composition that during combustion causes the green flame of the halide detector.
Select one:

A. Hydrogen

B. Chlorine

C. Carbon

D. Fluorine

E. Iodine

Answer 8

B. Chlorine

Question 9

Caution when burned the halocarbon refrigerants containing fluorine produce a very toxic _____ gas.
Select one:

A. Sulphur dioxide

B. Mustard

C. Hydrogen sulphide

D. Phosgene

E. Carbon monoxide

Answer 9

D. Phosgene

Question 10

What personal protective equipment (PPE) is required when charging a system with refrigerant?
Select one:

A. Face shield

B. Goggles

C. Rubber gloves

D. Encapsulated suit

E. Self contained breathing apparatus

Answer 10

B. Goggles

Question 11

Purge systems are required on refrigeration systems that operate:
Select one:

A. Above atmospheric temperature

B. Only with ammonia as the refrigerant

C. Below atmospheric pressure

D. Without a qualified operator in attendance

E. Below atmospheric temperature

Answer 11

C. Below atmospheric pressure

Question 12

The pressurizing gas is admitted to the refrigeration system through the _____ valve.
Select one:

A. Charging

B. King

C. Queen

D. Isolation

E. Drain

Answer 12

A. Charging

Question 13

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:
Select one:

A. Corrode metal parts

B. Plug the expansion valve

C. Restrict cooling water flow

D. Clog the condenser

E. Coat the evaporator

Answer 13

A. Corrode metal parts

Question 14

An alternate method to leak testing with a soap solution when using nitrogen is the:
Select one:

A. X-ray radiography

B. Infrared scanner

C. Magnetic flux tester

D. Ultraviolet scanner

E. Ultrasonic detector

Answer 14

E. Ultrasonic detector

Question 15

The refrigeration system condenser pressure should be slightly higher than the saturation pressure corresponding to the temperature of the refrigerant in the:
Select one:

A. Upstream side of the compressor

B. Accumulator

C. Evaporator

D. Condenser

E. Downstream side of the expansion valve

Answer 15

D. Condenser

Question 16

It may be illegal to _____ a refrigeration system without determining the location of and repairing the system leak.
Select one:

A. Simply add refrigerant to

B. Drain refrigerant from

C. Change the compressor of

D. Flush the condenser of

E. Evacuate the evaporator of

Answer 16

A. Simply add refrigerant to

Question 17

In a process called “copper plating” the acids remove copper from heat exchanger surfaces and redeposit it at points of:
Select one:

A. High flow

B. Low pressure

C. Low temperature

D. High pressure

E. High temperature

Answer 17

E. High temperature

Question 18

If a refrigeration system is not adequately evacuated before being charged with refrigerant the air that remains will accumulate as a _____ causing high compressor discharge pressures and temperatures.
Select one:

A. Refrigerant inhibitor

B. Condensable gas

C. Non-condensable gas

D. Non-condensable liquid

E. Condensable liquid

Answer 18

C. Non-condensable gas

Question 19

During charging of the refrigeration system short cycling of the compressor should be avoided due to the starting stress which is placed on the:
Select one:

A. Compressor motor

B. Expansion valve

C. Evaporator level control

D. Compressor valves

E. Condenser cooling water valve

Answer 19

A. Compressor motor

Question 20

Why should oxygen not be used to pressurize a system for leak checking purposes?
Select one:

A. It could result in an explosion

B. An external source of moisture free oxygen is required

C. The oxygen can cause pitting of the parts of the system

D. Oxygen is not compatible with refrigerants

E. The oxygen combines with any non-condensable gases present to increase the system head pressure

Answer 20

A. It could result in an explosion