310S Heating, Ventilation and Air Conditioning (HVAC)

Question 1

What refrigerant replaced R-12 (Freon) in automotive A/C systems to reduce ozone depletion?

Accepted Answer

R-134a

Answer

R-22

Answer

R-410A

Answer

R-1234yf

Question 2

What is the primary function of the receiver-drier in an automotive A/C system?

Accepted Answer

To remove moisture and filter contaminants from the refrigerant

Answer

To compress the refrigerant vapour

Answer

To rapidly expand refrigerant and lower its temperature

Answer

To transfer heat from cabin air to the refrigerant

Question 3

In an A/C system using a fixed orifice tube, which component stores refrigerant and separates liquid from vapour on the low side?

Accepted Answer

Accumulator

Answer

Receiver-drier

Answer

Condenser

Answer

Thermostatic expansion valve

Question 4

In what physical state does refrigerant enter the evaporator during normal A/C system operation?

Accepted Answer

Low-pressure liquid/vapour mixture

Answer

High-pressure superheated vapour

Answer

High-pressure subcooled liquid

Answer

Low-pressure superheated vapour

Question 5

What is the primary function of the condenser in an automotive A/C system?

Accepted Answer

To release heat from the refrigerant to the outside air

Answer

To absorb heat from the passenger compartment

Answer

To filter and dry the refrigerant

Answer

To compress refrigerant vapour to high pressure

Question 6

In a TXV-type A/C system, what does the sensing bulb on the thermostatic expansion valve monitor?

Accepted Answer

Evaporator outlet temperature and pressure

Answer

Condenser outlet temperature

Answer

Compressor discharge pressure

Answer

Cabin air temperature

Question 7

What is the typical low-side (suction) pressure range for a properly charged R-134a system at approximately 25°C ambient temperature?

Accepted Answer

138–207 kPa (20–30 psi)

Answer

0–35 kPa (0–5 psi)

Answer

414–483 kPa (60–70 psi)

Answer

690–827 kPa (100–120 psi)