PIPE Elements 8

A refrigerating unit of one ton capacity can remove:
a. 500 Btu per min
b. 288 Btu per min
c. 200 Btu per min
d. 100 Btu per min

Too much oil in the compressor would
a. absorb too much refrigerant from the system
b. damage the expansion valve
c. cause leakage through the shaft seals
d. deposit oil on the condenser tubes

The refrigerant with the lowest boiling point is:
a. NH₃
b. CO₂
c. F-12
d. F-22

A ton of refrigeration is equal to the removal of:
a. 288

Which of the following would cause a high suction pressure?
a. expansion valve not open wide enough
b. expansion valve open too wide
c. king valve not open wide enough
d. dirty dehydrator

Which of the following would cause high head pressure?
a. dirty condenser
b. insufficient cooling tower
c. air in the cooling tower
d. all of the above

Which of the following would cause low head pressure?
a. too much cooling tower
b. insufficient refrigeration gas
c. insufficient cooling water
d. A and B

The principle of the mechanical refrigeration is
a. the absorption of temperature under heat

The function of the expansion valve is to
a. change the high pressure liquid to low pressure liquid
b. regulate the amount of liquid refrigerant to expansion coils
c. change the gas refrigerants to a liquid
d. shut off the flow of refrigerant to the condenser

The oil separator (trap) is located between the
a. compressor discharge valve and the condenser
b. condenser and the receiver
c. receiver and the king valve
d. receiver and the expansion valve

The purpose of the oil trap is
a. to remove oil from the charging tank
b. to add oil to the compressor
c. to remove oil from the refrigerating gas
d. none of the above

The boiling point of ammonia at atmospheric pressure is
a. -28⁰C
b. +28⁰C
c. +28⁰C
d. -28⁰F

The boiling point of CO₂ at atmospheric pressure is
a. +10⁰F
b. -110⁰C
c. +110⁰C
d. -110⁰C

The boiling point of Freon at atmospheric pressure is
a. -22⁰F
b. +22⁰F
c. +32⁰F
d. -32⁰F

The dehydrator is located between the:
a. receiver and the king valve
b. receiver and the expansion valve
c. condenser and the king valve
d. condenser and receiver

The purpose of the dehydrator is to
a. remove oil from the refrigerant
b. add more refrigerant to the system
c. remove moisture from the refrigerant
d. remove moisture from the crankcase oil

Which of the following would you apply if a person got Freon in his eyes?
a. soapy water
b. sterile mineral oil
c. clean water
d. sodium bicarbonate

The thermal expansion valve
a. controls the amount of gas coming from the dehydrator
b. maintains a constant superheat of the gas leaving the evaporator coils
c. controls the amount of gas going to the receiver
d. removes trap oil from the refrigerant

Water in the refrigerant is liable to
a. freeze on the expansion seat and cut the flow of liquid refrigerant
b. emulsify the oil in the compressor
c. freeze in the king valve
d. clog the oil trap

The purpose of the scale trap is to:
a. control the amount of scale going to the compressor
b. remove insoluble gases from the refrigerant
c. remove dirt

A double seated valve allows the valve to be:
a. packed only in the closed position
b. packed in wide open or closed position
c. operated as a suction or discharge valve
d. removed for replacement without shutting down

Sensible heat
a. can be measured with a thermometer
b. cannot be measured with a thermometer
c. changes in the receiver tank
d. increases with the cold

The latent heat of fusion is the amount of heat required to convert
a. two lbs of ice at 32⁰F to one lb of ice at 32⁰F
b. one lb of ice at 32⁰F to one lb of water 32⁰F
c. one lb of ice at 32⁰F to one lb of steam 32⁰F
d. two lbs of ice at 32⁰F to one lb water at 32⁰F

The latent heat of vaporization of water is
a. 144 Btu
b. 940 Btu
c. 970 Btu
d. 288 Btu

The latent heat of vaporization is the amount of heat required to convert
a. one lb of water at 212⁰F to one lb steam at 212⁰F
b. one lb of water at 180⁰F to one lb of steam at 180⁰F
c. two lbs of water at 212⁰F to one lb of steam at 212⁰F
d. one lb of ice at 32⁰F to one lb of steam at 212⁰F

Too high suction pressure could be caused by
a. expansion valve open too wide
b. leaky suction valves
c. expansion valve bulb not working properly
d. any of the above

How is an ammonia system purged so that the operator will not be overcome by the fumes?
a. into that atmospheric line
b. into a bucket of water
c. into a bucket of lube oil
d. back into compressor

How is CO₂ system purged?
a. when CO₂ comes out

How is Freon system purged?
a. the same as the ammonia system
b. the same as the CO₂ system
c. back to the extra supply bottle
d. with a reefer pump

The solenoid valve is
a. 144 Btu
b. 288 Btu
c. 940 Btu
d. 500 Btu

Where should you charge less than 6 pounds of refrigerant into a system?
a. any point downstream of the liquid line
b. on the low side of the system
c. on the high side of the system
d. the discharge service valve

Latent heat
a. can be measured with a thermometer
b. can be measured with a pyrometer
c. cannot be measured with a thermometer
d. changes as the refrigerant cools

Absolute zero is
a. 970⁰ below zero on the Fahrenheit scale
b. 460⁰ below zero on the Farenheit scale
c. 144⁰ below zero on the Farenheit scale
d. the same as zero on the Centigrade scale

When the evaporator coils are located in the ice box

The amount of CO₂ or Freon in a cylinder is measured by
a. pressure
b. volume
c. weight
d. psi

The solenoid valve is controlled by
a. the amount of liquid in the system
b. the amount of gas in the system
c. the temperature in the condenser
d. the thermal switch operated by the icebox temperature

The purged valve is located
a. in the lowest part of the system
b. in the highest part of the system
c. on the receiver discharge
d. on the evaporator coils

The system should be purged
a. while the system is operating
b. while starting up the system
c. after the system has been shutdown for a few hours
d. once a week

The function of the compressor is to
a. pull the refrigerant gas through the system
b. increase the pressure of the refrigerant
c. discharge the refrigerant to the condenser
d. all of the above

The expansion valve is located between the
a. receiver and evaporator
b. evaporator and compressor
c. compressor and condenser
d. condenser and receiver

If frost forms on the cylinders

Which of the following would cause a high head pressure?
a. icebox door left open
b. insufficient cooling water
c. too much cooling water
d. suction valve not open enough

The high pressure side of the system is sometimes refered to as the
a. suction side
b. cold side
c. hot side
d. filling side

A ton of refrigeration is equal to the cooling effect of
a. 2000 lbs of ice melting in 24 hrs
b. 2000 lbs of ice melting in 12 hrs
c. 2000 lbs of ice melting in 24 hrs
d. 2240 lbs of ice melting in 24 hrs

The scale trap (liquid strainer) is located between the
a. compressor and oul separator
b. king(liquid) valve and expansion valve
c. expansion valve and evaporator coils
d. evaporator coils and compressor

When there is Freon leak

Which of the following could be used to check a leak in an ammonia system?
a. litmus paper
b. halide torch
c. sulphur stick
d. A and C

Valves and piping in an ammonia system are made of
a. iron
b. brass
c. copper
d. bronze

In an ammonia system

Freon is
a. colorless
b. odorless
c. nonpoisonous
d. all of the above

Which of the following gasket materials should be used on a Freon system?
a. metallic
b. asbestos
c. rubber
d. A and B

A double-pipe condenser has
a. two piping system side by side

Air can be prevented from getting into the system by
a. keeping all glands and stuffing boxes on the high-pressure side tight
b. keeping the dehydrator clean at all times
c. keeping all glands and stuffing boxes on the low-pressure side tight
d. running the refrigerant through the aerator

The agent used in an indirect refer system is
a. sodium chloride
b. potassium chloride
c. calcium chloride
d. A and C

An ammonia leak will turn litmus paper
a. blue
b. red
c. green
d. yellow

A sulphur stick burning in the presence of ammonia will give off a
a. dense yellow smoke
b. dense white smoke
c. dense red smoke
d. dense green smoke

If the compressor were to run continuously without lowering the temperature

Ammonia leaks in the condenser can be detected by
a. smelling the discharge water
b. applying litmus paper to the circulating water discharge
c. adding water to peppermint to the system and tracing the smell
d. applying a soapy mixture to the condenser heads and looking for bubbles

When purging an ammonia condenser into a bucket of water

Large leaks in a Freon system cannot always be detected with a halide torch because it changes color with slight test amount of Freon present. A large leak can be detected easier by applying
a. sheets of litmus paper to all joints and watch for color change
b. a soup suds solution

When the evaporator coils are located in a brine solution and the brine is pumped through the ice box

Obstruction of the expansion valve is usually caused by
a. congealed oil in the system
b. scale
c. water in the system
d. all of the above

Too low suction pressure could be caused by
a. dirty scale traps
b. shortage of refrigerant gas
c. too much oil in the system
d. any of the above

If an electrically operated compressor failed to start

The oil separator is located between the
a. evaporator and compressor
b. compressor and condenser
c. condenser and dehydrator
d. solenoid valve and the thermal expansion valve

To help person who have been exposed to ammonia gas

If the compressor short cycles on the low pressure cut-out

Ammonia will corrode
a. copper
b. bronze
c. brass
d. all of the above

The dehydrating agent in the Freon system is usually
a. slaked lime
b. sodium chloride
c. activated alumina
d. calcium chloride

If any of the electrically controlled devices in a Freon system malfunction

Many pressure gages on a Freon system have two dials or graduations on one gage. The two dials represent
a. pressure and temperature
b. liquid pressure and gas pressure
c. suction and discharge pressure
d. cooling-water inlet and outlet temperatures

A leaky discharge valve can usually be detected by
a. a fluctuating high-pressure gage
b. a drop in icebox temperature
c. a discharge pressure lower than normal
d. any of the above

The suction of a Freon should be
a. the pressure which corresponds with a temperature about 20F below the temperature of the ice box
b. the pressure which corresponds with a temperature of the icebox
c. the pressure which corresponds with a temperature about 20 above the temperature of the icebox
d. none of the above

The disadvantage of a CO₂ system over an ammonia system is the fact that:
a. the CO₂ system requires a larger prime mover
b. the CO₂ system operates at much higher pressure
c. the pipes and fittings of a CO₂ system must be of the high pressure type
d. all of the above

One disadvantage of a CO₂ system is the fact that
a. it is different to condense the refrigerant if the circulating water temperature is too high
b. it is difficult to condense the refrigerant if the circulating water temperature is too low
c. due to high pressure it is difficult to keep oil from mixing with refrigerant
d. it takes more refrigerant to keep the iceboxes cold

The crossover connection in an ammonia system can be used to
a. reduce the pressure on the discharge side of the condenser
b. hot-gas defrost
c. pump air out of the system
d. add refrigerant to the system

Another name for discharge pressure is
a. suction pressure
b. absolute pressure
c. head pressure
d. condenser pressure

Oil is used in the refrigerating system is
a. lube oil SAE 20
b. straight mineral oil
c. lube oil SAE 10
d. vegetable oil

The discharge pressure on the compressor should be
a. the pressure which corresponds to a temperature from 5 to 15⁰F below that of the condenser discharge
b. the pressure which corresponds to a temperature from 5 to 15⁰F higher than the condenser discharge
c. the pressure which corresponds to a temperature equal of the condenser discharge
d. none of the above

A leaky suction valve can usually be detected by
a. a fluctuating suction-pressure gage
b. a higher suction pressure
c. closing in on the suction valve having no effect on the suction pressure
d. any of the above

The purpose of relief valves on refrigerating machines is to
a. prevent overloading in the iceboxes
b. bypass the compressor when dehydrating
c. prevent excessive pressure in case of stoppage on the discharge side of the system
d. A and B

The relief valve on an ammonia machine is located
a. on the discharge pipe from the condenser
b. on the discharge pipe from the compressor
c. in the compressor head
d. A or B

The relief valve on a CO₂ machine is located
a. on the discharge pipe from the condenser
b. next to the king valve
c. on the discharge pipe between the compressor and the discharge valve
d. in the compressor head

Excess frost on the evaporator coils
a. keeps the icebox cooler
b. reduces the efficiency of the plant
c. takes the load off the compressor
d. does not affect the system

Air circulation in the icebox is accomplished by the use of
a. louver doors
b. hollow sidewalls
c. diffuser fans
d. air vents to decks

Before securing a compressor to do maintenance on it

Some causes of a noisy compressor are
a. worn bearings

Slugging is usually caused by
a. too much oil in the system
b. too much refrigerant in the system
c. expansion valve not operating properly
d. too much cooling water to condenser

Zinc rods are found in the
a. evaporator coils
b. salt water side of condenser
c. compressor crankcase
d. refrigerant side of crankcase

A double-trunk piston is used to
a. prevent gas from gettinf to crankcase
b. absorb some of the side trust
c. prevent oil from mixing with the refrigerants
d. all of the above

The purpose of the receiver is to
a. cool the refrigerant gas
b. separate the oil from the refrigerant
c. store the refrigerant
d. condense the refrigerant

When a pressure gage reads zero

The heat used to change a solid to a liquid is called
a. latent heat of fusion
b. sensible heat fusion
c. latent heat of liquid
d. specific heat of fusion

The heat used to change a gas to a vapor is called
a. latent heat of fusion
b. latent heat of vaporization
c. specific heat of vaporization
d. latent heat of the gas

Sweating of the crankcase is caused by
a. too much superheat
b. insufficient superheat
c. expansion valve hang up
d. too much oil in the system

If an automatic Freon system will not start up

The cooling-water side of the condenser should be opened for inspection every
a. six months
b. year
c. two years
d. three months

If the thermal expansion vakve becomes inoperative the iceboxes will have to be controlled by the
a. solenoid valve
b. manual expansion valve
c. king valve
d. manual solenoid valve