Exam 54: Heating and Air Conditioning

A liquid will boil at a lower temperature when it is put under pressure.

Which statement is false ?

Technician A says the compressor can pump both liquids and vapor. Technician B says the compressor is driven off the crankshaft by a belt. Who is correct?

Refrigerant is a low-pressure liquid as it leaves the condenser.

What are barrier hoses?

____________________ may also be referred to as SUVA.

Technician A says an A/C system using CO₂ [carbon dioxide] for a refrigerant will not contribute to global warming and is environmentally friendly. Technician B says CO₂ refrigerant does not need to be recovered and recycled. Who is correct?

Hybrid vehicles use an electrically driven compressor that needs a specific oil to operate properly.

When the defroster is selected by the driver the air conditioning will turn on to remove moisture from the vehicle's interior.

Technician A says a hybrid vehicle has a large reservoir of liquid refrigerant to keep the passenger compartment cool during long periods when the engine is shut down. Technician B says some hybrid vehicles have electrically driven A/C compressors. Who is correct?

R-134a is a hydrofluorocarbon.

The blower motor fan is sometimes referred to as a(n)____________________ cage.

A vehicle with insufficient heater performance is being discussed. Technician A says the problem could be a stuck-open engine thermostat. Technician B says air could be trapped inside the heater core. Who is correct?

Most current HVAC systems use electric servomotors to move the various doors.

The largest and coolest line/hose in the A/C system is the ______ line.

A heating system includes all the following parts EXCEPT:

Identify three common types of air-conditioning compressors.

The dash-mounted switch and the blower motor ____________________ block are used to control the blower motor speed.

When the ____________________ door is closed, outside air is blocked from entering the ventilation system while air from the interior of the vehicle is drawn into the heater blower.

Technician A says refrigerant leaves the compressor as a high-pressure liquid. Technician B says the condenser changes the high-pressure liquid refrigerant into a high-pressure vapor. Who is correct?