Modern Chap 52 - Review questions

Question 1

A field-erected system is a way of referring to a _______ system?

a) packaged
b) electrical
c) vending
d) split

Answer 1

d) split

Question 2

Most municipalities require a technician to obtain a _______ before a commercial refrigeration installation can be made

a) inspection
b) permit
c) specification sheet
d) standing pressure test

Answer 2

b) permit

Question 3

the discharge line from the compressor should be ______ to the condenser

a) kept as level as possible
b) looped
c) sloped downward
d) sloped upward

Answer 3

c) slanted downward

Question 4

All of the following devices are used to prevent excessive pressure in the condensing unit, except;

a) check valves
b) pressure controls
c) rupture discs
d) spring-loaded relief valves

Answer 4

a) check valves

Question 5

A sensing bulb for a thermostatic expansion valve should never be mounted on the _____ of the tube

a) bottom
b) left side
c) right side
d) all of the above

Answer 5

a) bottom

Question 6

A _______ should be connected between a single evaporators outlet and the suction line manifold

a) check valve
b) EPR
c) TXV
d) sensing valve

Answer 6

b) EPR

Question 7

The suction line maintains a gradual slope downward from the evaporator to the compressor in order to

a) aid liquid refrigerant circulation
b) aid oil returning to the compressor
c) prevent moisture from accumulating on the low side
d) prevent vapour from condensing into a liquid

Answer 7

b) aid oil returning to the compressor

Question 8

When tubing must run through a floor or wall, use short runs of _______ to protect the tubing

a) conduit
b) ductwor
c) soft ACR tubing
d) tubing clamps

Answer 8

a) conduit

Question 9

Shutoff valves in refrigerant lines _______

a) require using a refrigeration service valve wrench
b) should be hand operated
c) should be operated automatically
d) should have backup bypass solenoid operation

Answer 9

b) should be hand operated

Question 10

The size of a filter-drier is based on the following criteria, except;

a) compressor horsepower
b) compressor operating cycle
c) refrigerant quantity and type
d) risk of galvanic action

Answer 10

d) risk of galvanic action

Question 11

In a __________ compressor, the compressors crankshaft is connected either directly to the motor shaft or by means of a belt

a) open drive
b) hermetic
c) condensing
d) solenoid

Answer 11

open drive

Question 12

Before a system can be operated, a leak test must be performed by building up system pressure using

a) ammonia
b) nitrogen
c) oxygen

Answer 12

b) nitrogen

Question 13

Low-side charging involves adding refrigerant vapor to a system through the

a) discharge service valve
b) liquid receiver
c) queen valve
d) suction service valve

Answer 13

d) SSV

Question 14

High-side charging involves adjusting a ________ into position and adding liquid refrigerant though it

a) access port on a evaporator pressure regulator
b) access port on a filter drier
c) liquid receiver service valve
d) suction service valve

Answer 14

c) liquid receiver service valve

Question 15

One method of starting a multiple evaporator system requires the technician to throttle the ________

a) evaporator pressure regulator
b) discharge service valve
c) suction service valve
d) thermostatic expansion valve

Answer 15

c) suction service valve

Question 16

Explain why domestic refrigeration systems or other small-capacity systems are not usually covered or included in a municipalitys codes?

Answer 16

Because these systems are inspected and certified by the manufacturer prior to shipping to customer

Question 17

Explain why a flare nut used on a flare connection between an expansion valve and an evaporator in a commercial refrigeration system must be sealed after being secured in place. What could happen if the flare nut is not sealed?

Answer 17

It must be sealed form moisture or else ice could form and potentially collapse the tubing

Question 18

Explain why sensing bulb mounting straps should be made of a material that conducts heat well?

Answer 18

so heat can be transferred across the surface of the entire sensing bulb not just the area it comes in contact with

Question 19

Explain why plastic straps should not be used to mount a sensing bulb to suction line tubing?

Answer 19

temperature changes will eventually break the strap

Question 20

Explain why the suction line should be mounted with a slight slope toward the compressor?

Answer 20

to aid oil returning to the compressor

Question 21

Explain why vibration absorbers are necessary in some commercial refrigeration systems?

Answer 21

to prevent leaks cause by compressor vibration

Question 22

Explain why it is recommended that low-side charging only be used to charge smaller commercial systems or to “top off” the existing charge in a system?

Answer 22

Since refrigerant vapor is much less dense than liquid refrigerant, it takes longer to charge a system with vapor than it would with a equal weight of liquid refrigerant