RACT Unit 22 Review questions/Practice test

Question 1

Why are some water-cooled condensers cleaned with brushes and others with chemicals?

a) chemicals are only used on outdoor condensers, indoor condensers are cleaned with brushes
b) some water-cooled condensers will accumulate scale while others do not
c) all water-cooled condensers are hermetically sealed and cannot be cleaned with brushes
d) some condenser tubes are not straight and will not allow brushes to pass through them

Answer 1

d) some condenser tubes are not straight and will not allow brushes to pass through them

Question 2

The three materials of which air-cooled condensers are normally made are _______

a) brass, aluminum, and cast iron
b) brass, copper, and steel
c) copper , aluminum, and steel
d) copper, cast iron, and brass

Answer 2

C) copper, aluminum, and steel

Question 3

One of the differences between air-cooled and water-cooled condensers is the _______________

A) compressor discharge line temperature

B) Type of compressor used

C) Refrigerant condensing temp

D) Type of refrigerant used

Answer 3

Refrigerant condensing temperature

Question 4

When is the most heat removed from the refrigerant in the condensing process?

A) when the liquid refrigerant leaves the condenser

B) when the vapour enters the receiver

C) During the change in state from a liquid to a vapour

D) During the change in state from a vapour to a liquid

Answer 4

D) during the change in state from a vapour to a liquid

Question 5

After heat is absorbed into the water in a water-cooled condenser, the water can be ____________

a) treated with chemicals and piped to a chiller
b) wasted down the drain or sent to a cooling tower
c) filtered and used for drinking water
d) filtered and then treated with chemicals before being reused domestically

Answer 5

b) wasted down the drain or sent to a cooling tower

Question 6

A water-cooling tower capacity is governed by what aspect of the ambient air temp?

a) dry-bulb temperature
b) wet-bulb temperature
c) altitude
d) enthalpy of the air

Answer 6

b) wet-bulb temperature

Question 7

When a standard-efficiency air-cooled condenser is used, the condensing refrigerant will normally be _________ above the ambient air temperature

A) 15F

B) 60F

C) 45F

D) 30F

Answer 7

30F

Question 8

Fan cycling, air shutters or dampers, condenser flooding, and VFD condenser fan motors are all methods for controlling __________

a) evaporator capacity
b) electrical efficiency
c) suction pressure
d) head pressure

Answer 8

d) head pressure

Question 9

An outdoor air-cooled condenser that has a vertical coil can be affected by the ___________

A) refrigerant oil type

B) prevailing winds

C) indoor ambient temperature

D) municipal water temperature

Answer 9

B) Prevailing winds

Question 10

Air-cooled condensers are ______________

a) being phased out due to their inefficiencies
b) much more efficient than water-cooled cond.
c) less efficient than water-cooled condensers
d) the most efficient condensers on the market

Answer 10

c) less efficient than water-cooled condensers

Question 11

The type of condenser that has straight copper tubes that are fastened into an end sheet within a steel shell that is typically used in large installations is the _____________ condenser

a) shell-and-tube
b) shell-and-coil
c) tube-within-a-tube
d) air-cooled

Answer 11

a) shell-and-tube

Question 12

On a system that uses a floating head pressure, ____________________

a) the condenser must be located outdoors
b) more system heat is available for heat reclaim coils
c) the amount of heat discharged from the condenser is extremely high
d) less system heat is available for heat reclaim coils

Answer 12

d) less system heat is available for heat reclaim coils

Question 13

When the hot discharge gas enters the compressor, it is first _______________

a) condensed
b) de-superheated
c) vaporized
d) sub-cooled

Answer 13

De-superheated

Question 14

A 2-ton wastewater system that operates approximately 16hours per day would use about __________gallons of water per day

a) 5760
b) 2880
c) 7880
d) 11,520

Answer 14

2880?

Question 15

A 10-ton water-cooled system that recirculates water through a cooling tower averages 16 hours of run time per day. The amount of water that would be circulated in a day would be about __________ gallons

Answer 15

3 x 10 x 16 x 60 = 28,800

Question 16

In a water-cooled system that recirculates water through a cooling tower, the refrigerant in the condenser typically condenses at _________ above the leaving water temperature

a) 20F
b) 25F
c) 10F
d) 30F

Answer 16

10F

Question 17

A system that uses heat from the compressor discharge line to provide heated air or water to a conditioned space is called a _____________ system

a) water recirculating
b) energy recovery ventilator
c) latent boost
d) heat reclaim

Answer 17

d) heat reclaim

Question 18

A typical water-cooling tower can cool the water to within _____ of the ambient air wet-bulb temp

a) 3 to 4F
b) 5 to 6F
c) 9 to 10F
d) 7 to 8F

Answer 18

d) 7 to 8F

Question 19

Due to the seasonal temp variations of municipal water, a wastewater system ______________

a) has a constant water flow rate to maintain adequate head pressure
b) should have an auxiliary air-cooled condenser to stabilize system pressures
c) has no definite refrigerant-to-water temp relationship
d) has a defined refrigerant-to-water temp relationship

Answer 19

c) has no definite refrigerant-to-water temperature relationship

Question 20

The component that varies the flow of water through a water-cooled condenser to maintain a stable head pressure is called a _________

a) ORI head pressure valve
b) low-ambient control valve
c) ORD head pressure control
d) water-regulating valve

Answer 20

d) water regulating valve

Question 21

Briefly describe what is meant by floating head pressure and tell why it is used in refrigeration and AC systems?

Answer 21

It’s the term for attaining the lowest possible condensing pressure. These systems allow the condensing press to follow ambient temperature as the seasons swing from summer to winter

Question 22

How to flush impurities from a water-regulating valve that is on a water-cooled condenser?

Answer 22

By using a brush or chemicals

Question 23

Name two problems a refrigeration system may have if the condensing unit is exposed to a low ambient condition when not equipped with a low-ambient head pressure control valve;

Answer 23

1. expansion device could starve evaporator

2. less heat to be available for the heat reclaim coils to heat buildings

Question 24

briefly explain what is meant by condenser splitting and explain its main advantage:

Answer 24

Dividing condenser into two equal circuits to avoid flooding. Reduces extra ref charge needed for condenser flooding

Question 25

A device that passes outside air over water to remove the system heat is a _________ a) shell-and-coil condensers b) water tower c) cooling tower d) shell-and-tube-condenser

Answer 25

c) cooling tower

Question 26

Natural draft, forced draft, and evaporative are all types of; a) cooling towers b) package refrigeration systems c) wastewater systems d) refrigerant phases

Answer 26

a) cooling towers

Question 27

Condensing temperatures can be reduced by reducing the condenser surface area True or False

Answer 27

False

Question 28

For every 1 degree rise in suction gas temperature returning to the compressor, there will be a ________ degree rise in the compressor’s discharge temperature a) 10 b) 1 c) 30 d) 5

Answer 28

b) 1

Question 29

A ____________ can be piped into the high-side of the system to cycle the condenser fan on and off during a low ambient condition a) thermostat b) pressure control c) head pressure regulator d) thermostatic expansion valve

Answer 29

b) pressure control

Question 30

On a system that uses condenser flooding to control head pressure during low ambient conditions, the receiver should be sized so that it is a) 80% full when it contains the entire system charge b) 20% full when the system is operating during a low ambient condition c) 50% full at all times, during all conditions d) 100% full when it contains the entire system charge

Answer 30

a) 80% full when it contains the entire system charge

Question 31

Any refrigerant receiver should be able to hold all of the systems charge and still have a 25% vapour head for safety a) true b) false

Answer 31

b) false

Question 32

Condenser flooding is accomplished by _____________ in both mold and cold weather to keep the head pressure constant a) having enough refrigerant in the system to raise the suction pressure b) having enough refrigerant in the system to flood the evaporator c) having enough refrigerant in the system to flood the condenser d) applying heat to the compressor crankcase

Answer 32

c) having enough refrigerant in the system to flood the condenser

Question 33

Low ambient controls are used on ___________ to maintain head pressure during low ambient conditions a) air-cooled condensers b) waste water systems c) water-cooled condensers d) cooling towers

Answer 33

a) air-cooled condensers

Question 34

_______________ systems use water once, it is then piped to a drain a) air-cooled condenser b) package c) recirculating water d) wastewater

Answer 34

d) wastewater