WorksheetsHAC-101 Chap 58 Principles of HVAC Test B
Total questions: 20
Worksheet time: 10mins
Air conditioning systems absorb heat from a cab interior through a(n)
a. Condenser
b. Evaporator
c. Compressor
d. Blower
How do the late-model vehicles help maintain a cleaner and dust-free cab interior?
a. Equipped with an air ventilator located at the cab air inlet
b. Equipped with an air filter located at the cab air inlet
c. Equipped with an air compressor located at the cab air inlet
d. Equipped with an air filter located at the cab air outlet
Moisture condensed on a cold _______ helps remove dirt and other particulates.
a. Condenser
b. Evaporator
c. Compressor
d. Ventilator
Which measurement of heat best describes the quantity of heat required to produce a change of state from a solid to a liquid or a liquid to a gas?
a. Latent heat
b. Radiant heat
c. Specific heat
d. Sensible heat
Heating is regulated by circulating engine coolant through an in-cab heat exchanger called a
a. Radiator core
b. Heat core
c. Condenser
d. Pressure control switch
Technician A says removing heat from an object or substance is simple, because cold always moves toward a warmer object. Technician B says all that is necessary for cooling is to provide an even warmer substance for cold to flow into. Who is correct?
a. Technician A
b. Technician B
c. Both Technician A and Technician B
d. Neither Technician A nor Technician B
Which of the following holds true for refrigeration systems?
a. They add moisture to the air passing through the evaporator.
b. The compressor is an engine-driven pump that decreases refrigerant pressure.
c. Air conditioning and refrigeration systems transfer heat from the cab and passenger compartment to the air stream outside the vehicle.
d. The refrigeration system operates in an open loop.
The thermal expansion valve device lowers the pressure of the warm, high-pressure liquid refrigerant entering the
a. Evaporator
b. Condenser
c. Compressor
d. Orifice
Which of these holds true for H-Valve thermal expansion valve (TXV) operation?
a. TVX meters the refrigerant into the evaporator at a variable rate.
b. It maintains the evaporator at low temperature and pressure.
c. Spring tension acting on the orifice ball regulates the quality of refrigerant flow.
d. Inlet temperature also can change the position of the linkage.
The coldest air temperature from the evaporator is when the blower is operated at its
a. Molecular
b. Slowest
c. Fastest
d. Road
An important component in the cooling action of the evaporator is the
a. Blower fan
b. Receiver drier
c. Condenser fan
d. Driver evaporator module
Technician A says accumulators often incorporate an important diagnostic aid-the refrigerant sight glass. Technician B says accumulators collect liquid refrigerant leaving the evaporator and separate vapor from liquid before the refrigerant enters the compressor. Who is correct?
a. Technician A
b. Technician B
c. Both Technician A and Technician B
d. Neither Technician A nor Technician B
The_______ is located in the low-pressure side of the system.
a. Dryer
b. Accumulator
c. Compressor
d. Condenser
What is the viscosity of the oil used in reciprocating piston compressors?
a. 10-30w
b. 15-40w
c. 85-100w
d. 90-120w
When released into the atmosphere, HFO-1234yf decomposes, giving it a lifetime of
a. 11 years
b. 11 days
c. 200 days
d. 2500 years
The air conditioning controls are necessary to
a. Adjust operator comfort levels in the cab of the vehicle
b. Expose major components to damage
c. Improve freezing inefficiency of the system
d. Operate an evaporator by switching it on and off
What switch has three sets of internal contacts?
a. Trinary
b. Thermostatic
c. Pressure-cycling
d. Ambient temperature
Which of the following best explains APADS?
a. The unit receives input from two trinary switches and a thermostat.
b. Operates both air conditioning controls and analog controls
c. Extends the lifespan of the air conditioning system on medium- and heavy-duty trucks
d. The output signals are interpreted by control logic.
Whenever a system fault is detected, the
a. Air conditioning protection and diagnostic system (APADS) receives inputs from the vehicle data link
b. Compressor is not allowed to run
c. Air conditioning system is turned off
d. APADS broadcasts diagnostic information over the data bus
When discussing the function of the air distribution system, Technician A says actuators for the cab air door controls are operated by brush-type stepper motors providing low power consumption. Technician B says a Hall-effect sensor is built into many motors to provide position feedback to the microcontroller to verify the actuators are correctly positioning. Who is correct?
a. Technician A
b. Technician B
c. Both Technician A and Technician B
d. Neither Technician A nor Technician B
