Question 1

What component dissipates the heat from the controlled space?&#10;A) The evaporator&#10;B) The condenser&#10;C) The compressor&#10;D) The thermostatic expansion valve

Accepted Answer

The condenser is responsible for dissipating the heat from the controlled space by releasing it outside of the system. The evaporator absorbs heat from the controlled space, the compressor compresses the refrigerant and the thermostatic expansion valve regulates the flow of refrigerant.

Question 2

What refrigerant is currently being used in refrigeration equipment?&#10;A) R-12 and R-404a&#10;B) R-22 and R-502&#10;C) R-134a and R-12&#10;D) R-134a and R-404a

Accepted Answer

R-134a and R-404a are currently the most commonly used refrigerants in refrigeration equipment, as they have a lower impact on the environment compared to other refrigerants. R-12 and R-22 are being phased out due to their contribution to ozone depletion. R-502 is also being phased out due to its high global warming potential.

Question 3

Why is it necessary to precool the product before loading?&#10;A) To prevent the product from spoiling.&#10;B) To ensure the unit can achieve the set point.&#10;C) Because the unit does not have the refrigeration capacity to cool the product only maintain the temperature.&#10;D) All of the above are reasons to precool the product

Accepted Answer

All of the above are reasons to precool the product. Precooling helps prevent the product from spoiling, ensures the unit can achieve the set point, and is necessary because the unit may not have the refrigeration capacity to cool the product, only maintain its temperature.

Question 4

What directs the flow of air from the evaporator throughout the trailer?&#10;A) The evaporator fan.&#10;B) The chute.&#10;C) The reefer floor ducting.&#10;D) Both B and C direct air flow .

Accepted Answer

Both the chute and the reefer floor ducting work together to direct the flow of air from the evaporator throughout the trailer. The chute helps to distribute the air evenly while the floor ducting directs it along the length of the trailer. The evaporator fan helps to circulate the air, but it does not direct the flow on its own.

Question 5

A multi-temperature refrigeration unit does not share a common:&#10;A) Condenser&#10;B) Evaporator&#10;C) Compressor&#10;D) Drive engine

Accepted Answer

A multi-temperature refrigeration unit has separate evaporators and controls for different temperature zones, but it typically shares a common compressor and condenser system. The drive engine is also typically shared. Therefore, the correct answer is B, as the multi-temperature refrigeration unit does not share a common evaporator.

Question 6

Why is a reefer floor manufactured in a corrugated design?&#10;A) To make the trailer lighter.&#10;B) To make the floor stronger.&#10;C) To allow for air flow underneath the product.&#10;D) To give fork trucks better traction.

Accepted Answer

The corrugated design of a reefer floor allows for air circulation underneath the cargo, which is crucial for maintaining consistent temperature control throughout the refrigerated trailer.

Question 7

If the ambient temperature is 80&#176;F and the unit thermostat is set at 32&#176;F and the box temperature is 34&#176;F what mode of operation will the unit be in?&#10;A) High speed heat&#10;B) Low speed heat&#10;C) High speed cool&#10;D) Low speed cool

Accepted Answer

The unit will be in low speed cool mode because it needs to cool the box temperature down to 32°F, which is below the ambient temperature of 80°F.

Question 8

The refrigeration unit thermostat will not:&#10;A) Establish the switching point between heating and cooling cycles.&#10;B) Establish the switching point between high speed and low speed.&#10;C) Monitor the box temperature of the vehicle.&#10;D) Maintain the engine temperature.

Accepted Answer

The refrigeration unit thermostat is designed to control the temperature within the refrigerated space by establishing the switching points between heating and cooling cycles, and possibly between different operational speeds, but it does not maintain the engine temperature. Engine temperature is typically managed by the vehicle's cooling system, which operates independently of the refrigeration unit.

Question 9

The job of the condenser is:&#10;A) To heat refrigerant&#10;B) To remove heat from the controlled space&#10;C) Cool the controlled space&#10;D) Heat the controlled space

Accepted Answer

The job of the condenser is to remove heat from the controlled space. It does this by transferring the heat from the refrigerant to a cooling medium (usually air or water) flowing around the outside of the condenser coils. This causes the refrigerant to condense back into a liquid, which can then be pumped back into the evaporator to continue the cooling process.

Question 10

Even if a refrigeration unit is operating properly a load can still spoil due to:&#10;A) A load that was not precooled&#10;B) A trailer with poor insulation&#10;C) Improperly loaded trailer&#10;D) All of the above can cause the load to spoil

Accepted Answer

All of the above factors can contribute to a load spoiling, regardless of whether the refrigeration unit is functioning correctly. If a load was not precooled, it may not be able to reach its required temperature even with a working refrigeration unit. A trailer with poor insulation may not be able to maintain a consistent temperature, even if the refrigeration unit is functioning properly. Improperly loading a trailer can cause cold spots or areas where air is not able to circulate properly, leading to spoilage. Therefore, all of these factors can contribute to a load spoiling, even if the refrigeration unit is working correctly.

Question 11

What component controls engine high or low speed operation?&#10;A) The thermostatic expansion valve.&#10;B) The thermostat.&#10;C) The set point.&#10;D) The engine control module.

Accepted Answer

The answer of What component controls engine high or low...

Question 12

When a refrigeration unit starts short cycling because the trailer has been improperly loaded what component is tricked into thinking the temperature within the controlled space is sufficient?&#10;A) The box temperature&#10;B) The thermostat&#10;C) The evaporator inlet temperature sensor&#10;D) The evaporator outlet temperature sensor

Accepted Answer

The answer of When a refrigeration unit starts short cycling...

Question 13

When a trailer is loaded, what is the minimum recommended spacing between the product and the roof?&#10;A) 12 inches&#10;B) 11 inches&#10;C) 10 inches&#10;D) 9 inches

Accepted Answer

The answer of When a trailer is loaded, what is...

Question 14

When a unit is run in the auto stop/start mode and has automatically shut off what will trigger the unit to restart?&#10;A) Box temperature rises a predetermined amount&#10;B) Maximum off time limit has been reached&#10;C) Engine block temperature falls below a predetermined temperature&#10;D) Any of the above will initiate a restart

Accepted Answer

The answer of When a unit is run in the...

Question 15

Unlike a standard van trailer a reefer trailer is constructed with insulation in the floors, walls, ceiling, and doors. Insulating properties are also known as:&#10;A) Insulators&#10;B) Resilient&#10;C) &#34;R&#34; value&#10;D) Rigid value

Accepted Answer

The answer of Unlike a standard van trailer a reefer...

Deck 13: Truck Trailer Refrigeration Equipment