Font size
WorksheetsACR-110 Final Review
Total questions: 28
Worksheet time: 14mins
The temperature inside the temperature controlled environment is
ambient temperature.
box temperature.
setpoint.
Truck-trailer refrigeration equipment operates by bringing outside air into the box, cooling it, and then exhausting the warm, stale air to the outside.
True
False
Heat generated by a product as it ripens is
heat of transportation.
heat of perspiration.
heat of dissipation.
heat of respiration
Truck-trailer refrigeration equipment is designed to quickly reduce product temperature to the desired setpoint.
True
False
Setting the thermostat lower than the desired temperature increases unit output and shortens the time required to precool the box.
True
False
Important factors when loading temperature-sensitive product include:
The product should be pre-cooled to the correct temperature before loading.
The box should be pre-cooled to the correct temperature before loading.
The unit should be turned off when loading.
All of the above.
Which of the following contributes to poor air circulation?
Product stacked directly on flat floors.
Pallets without adequate openings or that are improperly oriented.
Plastic wrap around pallet openings.
All of the above.
A refrigeration unit alternates between the heat and cool modes more often than normal. This is called
Auto stop start
Auto cycle
Modulation
Short cycling.
The heat absorbed by the refrigerated compartment while it is parked empty in the sun is called:
Sensible heat
Latent heat
Residual heat
Super heat
1. The compressor
is responsible to pump the refrigerant through the system.
separates liquid refrigerant from vaporous refrigerant.
acts as a storage tank for liquid refrigerant
releases the heat from the controlled space to the outside air.
Service valves allow the technician to install a manifold gauge set for testing purposes and __________ of the refrigeration system
evacuation
recharging
purging
all of the above
The function of the condenser is:
To release the heat from the controlled space to the outside air.
To store liquid refrigerant until it is needed.
To filter the refrigerant and remove dirt and sludge.
To absorbed heat from the controlled space
The expansion valve
Creates low pressure in the condenser.
Creates high pressure in the evaporator.
Controls the pressure and boiling point in the condenser and evaporator.
All of the above
Which components divide the system between the low side and high side?
The compressor and expansion valve
The expansion valve and condenser
The condenser and evaporator
All of the above
What is the purpose of a heat exchanger?
To remove the heat from the controlled space.
To enable the refrigeration system to operate more efficiently.
To facilitate the condensing of the superheated refrigerant in the condenser section.
To cool the vaporous refrigerant returning to the compressor.
In regards to the thermostatic expansion valve, which force applied to the diaphragm causes the valve to open allowing refrigerant to pass?
Spring pressure.
Evaporator outlet pressure.
Compressor suction pressure.
Sensing bulb pressure.
The purpose of the evaporator is
To allow refrigerant to change states from gas to liquid before reaching the TXV
To aid in the cooling process of the drive engine
To allow the refrigerant to absorb heat from the controlled space.
To dry up any moisture that that may condense on the fins of the evaporator.
What is the function of the accumulator?
To enable the refrigeration system to operate more efficiently.
To allow the refrigerant to absorb heat from the controlled space.
To creates high pressure in the evaporator.
To separate liquid refrigerant from vaporous refrigerant before it enters the compressor.
Why do some truck-trailer refrigeration units use a suction pressure regulator?
To boost suction pressure thereby increasing compressor output.
To limit suction pressure protecting the drive engine from being overloaded.
To create high pressure in the evaporator.
To controls the pressure and boiling point in the condenser..
Both B and C are correct.
There are two forces working together to try to close the TXV. What are these forces?
Equalizer and spring pressure
Suction bulb and equalizer pressure
Suction bulb, equalizer and spring pressure all work together to close the expansion valve,
Sensing bulb and spring pressure
In order to improve the performance of the heat/defrost mode, which component allows hot gas to enter the receiver tank?
Condenser pressure bypass.
Accumulator bypass valve.
Condenser check valve.
Bypass check valve.
What is the purpose of the discharge check valve on a solenoid control system?
To prevent liquid refrigerant from migrating from the condenser to the compressor in the off cycle
To trap refrigerant in the receiver
To prevent liquid refrigerant from flowing from the receiver to the hot gas line.
To prevent refrigerant from flowing into the evaporator.
In what position must the manual liquid line shutoff or (king valve) be to stop the flow of refrigerant on a unit with a solenoid control system?
Back seated
Front seated
Mid seated
Removed
The purpose of the TXV is to meter refrigerant into the evaporator in order to maintain a constant _____________ of the refrigerant at the evaporator outlet.
superheat
pressure
subcooling
flow
If the discharge temperature should exceed safe limits on a solenoid control refrigeration system the ______________ will open to allow a small amount of liquid refrigerant into the suction line.
the TXV
SV3
fusible plug
quench valve
The state of the refrigerant returning to the compressor through the suction vibrasorber is a low-pressure low-temperature _______________.
subcooled liquid
subcooled vapor
superheated vapor
superheated liquid
When the solenoid control system is in the heat/defrost mode the hot gas line delivers high-temperature, high-pressure _______________ to the evaporator.
superheated liquid
superheated vapor
subcooled vapor
subcooled liquid
What is the only difference between the heat and defrost modes of operation?
Air is not circulated over the load in defrost mode.
Defrost mode can only be used when ambient temperature is greater than box temperature.
