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WorksheetsTHEORY TEST DVA 40083 AUTOMOTIVE AIR CONDITIONING TECHNOLOGY
Total questions: 40
Worksheet time: 20mins
State three (3) different phase in air-conditioning system.
Solid, water and steam
Ice, liquid and gas
Solid, liquid and gas
Liquid, water and steam
What type of heat transfer requires in air movement?
Radiation.
Conduction.
Convection.
Evaporation.
What is the purpose of conduction?
Transfer of heat in rays.
Transfer of heat by movement of warmed liquid or gas.
Transfer of heat by direct contact.
Transfer of heat from surrounding matter.
Which of the following describe sensible heat.
It causes a change of state .
It causes a temperature change.
It causes a liquid to boil.
It causes a solid to melt.
Which of the following best describes the low side of a system?
High pressure and high temperature
High pressure and low temperature
Low pressure and high temperature
Low pressure and low temperature
The refrigerant is circulated through the system by a ______________.
condenser
evaporator
compressor
thermal expansion valve
The boiling point of a liquid can be increased by raising the _______.
temperature
pressure
latent heat
sensible heat
Air-conditioning process works through a fluid which is called as ______________ that continuously changes state from liquid to gas and back to liquid.
element
insulator
conductor
refrigerant
When the refrigerant evaporates, it absorbs heat when it changes from liquid to gas. In which unit does this occur?
Filter dryer
Evaporator
Thermostat
Compressor
Which is the unit containing a desiccant to remove moisture from the system?
Receiver-drier
Accumulator
Evaporator
Condenser
The low side of the refrigerant cycle means ________________.
it has low pressure and temperature.
it begins at the compressor and ends at the expansion device.
that the refrigerant condenses.
it is called the liquid line.
The high side of the refrigerant cycle means it ________________.
has low pressure and temperature.
begins at the expansion device and ends at the compressor.
has higher pressures and temperatures.
the refrigerant boils or evaporates.
A ______________ is a variable valve that changes the size of the valve opening in response to the cooling load of the evaporator.
orifice tube
compressor
thermal expansion valve (txv)
receiver-dryer
What the basic designs of automotive air conditioning compressors?
Piston, vane and scroll.
Radial, piston and vane.
Radial, piston and vane.
Fixed scroll, moveable scroll and piston.
“Outside air” is also called ____________air.
recirculation
fresh
plenum
mode
The air inlet control door is also called ____________.
fresh air door.
recirculation door.
outside air door.
inside air door.
The low-side pressure is low and the high-side pressure is higher than normal. What is the most likely cause?
Low refrigerant charge level.
System is overcharged.
Restriction in the low-side fine.
Restriction in high-side line.
State the function of compressor pumps refrigerant.
High liquid that changes to a low liquid
Low liquid that changes to a high vapor
High vapor that changes to a high vapor
Low vapor that changes to a high vapor
To be sure that all of the moisture in air-conditioning system has been boiled and removed, a vacuum of at least ___________in. Hg should be drawn on the system for at least ____________ minutes.
29, 15
29, 60
30, 90
30, 120
Which of the following is not a CFC or HCFC?
R-134a.
R-410a.
R-12.
R-455a.
The thermistor type thermostat is located at the _____________.
condenser
evaporator
compressor
thermal expansion valve
What is the refrigerant inside a condenser?
Liquid.
Gas.
Liquid changing to a gas.
Gas changing to a liquid.
State the function of condenser?
Temporarily storing the refrigerant
Cooling and robbing the heat from the refrigerant
Control the amount of refrigerant
To change refrigerant from liquid to gas
Most air conditioning system cycles the compressor clutch in regular intervals to control _________.
condenser temperature
compressor pressure
evaporator temperature
expansion valve opening
State the refrigerant temperature which is discharge from a compressor.
120 ºC.
100 ºC.
80 ºC.
50 ºC.
The reading on a low side pressure gauge shows the numbers of “0” Psi when compressor running. What is the problem in the air conditioning system?
High temperature in air conditioning system
Expansion valve clogged
No compress in compressor
Blower motor not function
Which is the component that connect the compressor to the evaporator?
Suction hose
Accumulator
Discharge hose
Evaporator
Why the bubbles is shown at the sight glass during the air conditioning is running?
Refrigerant is not enough
Pressure switch not function
Compressor problem
Oil compressor is not enough
How many times should be evacuated moisture from a system air conditioning?
15 minutes
30 minutes
45 minutes
60 minutes
Which is the best way to remove refrigerant from a system?
Vent it into the atmosphere
Vacuum it using a vacuum pump
Capture by recovery machine
Open the pipe connection
How can refrigerant be contaminated with air?
The recovery unit hose is not tight
The system is not thoroughly evacuated before recharging
The technician uses sloppy service procedures
The performance test is not completed
1. What is the function of the diode in shown in the illustration above?
Increase voltage in the clutch coil circuit
Reduce voltage in the clutch coil circuit
Block the flow of current in the electrical system
Prevent voltage spikes in the electrical system
Which sensor is also called the ambient air temperature sensor?
Outside air temperature (OAT).
In vehicle temperature.
Discharge air temperature.
Evaporator outlet temperature.
What is the most common type of sun load sensor?
Potentiometer.
Negative temperature coefficient (NTC) thermistor.
Photodiode.
Positive temperature coefficient (PTC) thermistor.
Why modern vehicle air conditioning systems use an engine temperature sensor?
To prevent heater operation until the coolant is hot
To turns on the NC compressor after the engine has warmed up
To blocks A/C operation when the engine is cold
To allows heater operation as soon as the engine is started
Which sensor in the Automatic Climate Control system that determine the temperature of the incoming air?
Sun-load sensor
Ambient sensor
In-vehicle sensor
Throttle position sensor
Why do evacuating process need to be performed?
To remove moisture from air-conditioning system
To remove oil compressor from air-conditioning system
To recharger refrigerant
To recharger oil compressor
During a refrigerant system performance test, the high-side pressure instantly goes over 370 psi when the compressor is engaged. Which of the following is the most likely cause?
An overcharged system
An undercharged system
Moisture in the system
Expansion valve stuck open
Refrigerant system air contamination may be caused by?
Refrigerant system low-side leak
Improper system evacuation or insufficient evacuation time
Weak evacuation pump
Manifold gauge problem
Which type of air-conditioning unit mounting location?
Dash type
Trunk type
Dual type
Simple type
