Question 1

In a 2-ton capillary tube system, the unit does not develop full capacity. Head pressure is low and suction pressure is low. What is the problem?

Accepted Answer

The unit i...

Question 2

An air-cooled R-12 refrigeration system is operating normally with a suction pressure of 25 psig and a head pressure of 136 psig. Which of the following represents a possible set of operating pressures if the condenser fan motor burns out?

Accepted Answer

A)   high side 136 psig, low side 25 psig
B)   high side 100 psig, low side 15 psig
C)   high side 200 psig, low side 20 psig
D)   high side 180 psig, low side 35 psigE) A) and D)
F) B) and C)

Question 3

In a wastewater cooled system, the difference between the condensing temperature of the refrigerant and the leaving water temperature is approximately ____.

Accepted Answer

A)   10°F
B)   20°F
C)   30°F
D)   40°FE) None of the above
F) All of the above

Question 4

For each 12,000 Btu/h capacity, a water-cooled condensing unit and cooling tower combination will circulate approximately ____________________ GPM through the condenser.

Accepted Answer

The answer of For each 12,000 Btu/h capacity, a water-cooled...

Question 5

If a system has a(n) ___ for a metering device, the device will try to maintain evaporator superheat even with an excessive overcharge.

Accepted Answer

The answer of If a system has a(n) ___ for...

Question 6

Why is it that many products that require medium-temperature refrigeration will not freeze at 30°F?

Accepted Answer

Pure water freezes at 32°F. An...

Question 7

In a 2-ton capillary tube system, the unit does not develop full capacity. Head pressure is low and suction pressure is high. What is the problem?

Accepted Answer

The proble...

Question 8

Most water-cooling towers can cool the water that supplies the condenser to a temperature within ____________________°F of the wet-bulb temperature of the ambient air.

Accepted Answer

The answer of Most water-cooling towers can cool the water...

Question 9

Medium-temperature refrigerated cabinet temperatures range from ____.

Accepted Answer

A)   5°F to 20°F
B)   20°F to 35°F
C)   30°F to 45°F
D)   35°F to 50°FE) B) and C)
F) A) and D)

Question 10

A thermostatic expansion valve's capacity will drop if the pressure drop across the valve increases.

Accepted Answer

A) True 
 B)False

Question 11

For each 12,000 Btu/h capacity, a wastewater-cooled condensing unit uses approximately ____________________ GPM.

Accepted Answer

The answer of For each 12,000 Btu/h capacity, a wastewater-cooled...

Question 12

In a 2-ton TX valve system, the unit does not develop full capacity. Head pressure is high, suction pressure is slightly above normal, and subcooling is below normal. What is the problem?

Accepted Answer

The problem is a dir...

Question 13

Since many new replacement refrigerants are being used throughout the industry, a technician should rely on system temperatures to ease the troubleshooting process.

Accepted Answer

A) True 
 B)False

Question 14

High compression ratios will lead to lower compressor discharge temperatures.

Accepted Answer

A) True 
 B)False

Question 15

Because of the low refrigerant flow rate through the compressor and the system being undercharged, the 100% saturated vapor point in the condenser will be very low in the condenser, causing low condenser subcooling.

Accepted Answer

A) True 
 B)False

Question 16

Will the gauge readings be high or low with a system using a capillary tube that has a low refrigerant charge?

Accepted Answer

The answer of Will the gauge readings be high or...

Question 17

The approach of a cooling tower is the ____.

Accepted Answer

A)   difference between the entering and leaving wet-bulb temperatures
B)   number of degrees the water is cooled in the tower
C)   difference in temperature between the entering air wet-bulb temperature and the sump water temperature
D)   difference in temperature between the entering air web-bulb temperature and the water entering the towerE) A) and B)
F) A) and C) C

Question 18

In a high-temperature refrigeration unit, the boiling point of the refrigerant in the coil is normally ____ lower than the cabinet temperature.

Accepted Answer

A)   5°F to 15°F
B)   10°F to 20°F
C)   25°F to 35°F
D)   35°F to 46°FE) B) and C)
F) All of the above

Question 19

Dirty condenser coils are often the cause for inefficient condensers.

Accepted Answer

A) True 
 B)False  True

Question 20

A low refrigerant charge will cause a(n) ____________________ suction pressure, which will increase the compression ratio.

Accepted Answer

low

Exam 29: Troubleshooting and Typical Operating Conditions for Commercial Refrigeration

In a 2-ton capillary tube system, the unit does not develop full capacity. Head pressure is low and suction pressure is low. What is the problem?

Correct AnswerverifiedThe unit i...View AnswerShow Answer

An air-cooled R-12 refrigeration system is operating normally with a suction pressure of 25 psig and a head pressure of 136 psig. Which of the following represents a possible set of operating pressures if the condenser fan motor burns out?

Correct AnswerverifiedShow Answer

In a wastewater cooled system, the difference between the condensing temperature of the refrigerant and the leaving water temperature is approximately ____.

Correct AnswerverifiedShow Answer

For each 12,000 Btu/h capacity, a water-cooled condensing unit and cooling tower combination will circulate approximately ____________________ GPM through the condenser.

Correct AnswerverifiedShow Answer

If a system has a(n) ___ for a metering device, the device will try to maintain evaporator superheat even with an excessive overcharge.

Correct AnswerverifiedShow Answer

Why is it that many products that require medium-temperature refrigeration will not freeze at 30°F?

Correct AnswerverifiedPure water freezes at 32°F. An...View AnswerShow Answer

In a 2-ton capillary tube system, the unit does not develop full capacity. Head pressure is low and suction pressure is high. What is the problem?

Correct AnswerverifiedThe proble...View AnswerShow Answer

Most water-cooling towers can cool the water that supplies the condenser to a temperature within ____________________°F of the wet-bulb temperature of the ambient air.

Correct AnswerverifiedShow Answer

Medium-temperature refrigerated cabinet temperatures range from ____.

Correct AnswerverifiedShow Answer

A thermostatic expansion valve's capacity will drop if the pressure drop across the valve increases.

Correct AnswerverifiedShow Answer

For each 12,000 Btu/h capacity, a wastewater-cooled condensing unit uses approximately ____________________ GPM.

Correct AnswerverifiedShow Answer

In a 2-ton TX valve system, the unit does not develop full capacity. Head pressure is high, suction pressure is slightly above normal, and subcooling is below normal. What is the problem?

Correct AnswerverifiedThe problem is a dir...View AnswerShow Answer

Since many new replacement refrigerants are being used throughout the industry, a technician should rely on system temperatures to ease the troubleshooting process.

Correct AnswerverifiedShow Answer

High compression ratios will lead to lower compressor discharge temperatures.

Correct AnswerverifiedShow Answer

Because of the low refrigerant flow rate through the compressor and the system being undercharged, the 100% saturated vapor point in the condenser will be very low in the condenser, causing low condenser subcooling.

Correct AnswerverifiedShow Answer

Will the gauge readings be high or low with a system using a capillary tube that has a low refrigerant charge?

Correct AnswerverifiedShow Answer

The approach of a cooling tower is the ____.

Correct AnswerverifiedC

In a high-temperature refrigeration unit, the boiling point of the refrigerant in the coil is normally ____ lower than the cabinet temperature.

Correct AnswerverifiedShow Answer

Dirty condenser coils are often the cause for inefficient condensers.

Correct AnswerverifiedTrue

A low refrigerant charge will cause a(n) ____________________ suction pressure, which will increase the compression ratio.

Correct Answerverifiedlow

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Pure water freezes at 32°F. An...
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low