NATE Electrical and Controls

Question 1

What is the standard line voltage for most residential HVAC equipment in the United States?

Accepted Answer

240V/60Hz

Answer

120V/60Hz

Answer

208V/60Hz

Answer

277V/60Hz

Question 2

Which component in an HVAC control circuit is used to sense thermostat demand and energize the compressor contactor?

Accepted Answer

Control relay

Answer

Capacitor

Answer

Transformer

Answer

Thermistor

Question 3

What does the label 'R' on an HVAC thermostat terminal typically represent?

Accepted Answer

24V AC power from the transformer

Answer

Return air sensor

Answer

Reversing valve signal

Answer

Refrigerant charge indicator

Question 4

A single-phase motor fails to start and hums loudly. Which component is MOST likely the cause?

Accepted Answer

Start capacitor

Answer

Run capacitor

Answer

Contactor

Answer

Overload protector

Question 5

What is the purpose of a high-pressure cutout switch in an HVAC system?

Accepted Answer

Protect the compressor from excessive discharge pressure

Answer

Limit refrigerant charge

Answer

Regulate low-side pressure

Answer

Monitor suction line temperature

Question 6

When measuring AC voltage with a multimeter, what type of reading does a standard digital multimeter display?

Accepted Answer

RMS (root mean square) voltage

Answer

Peak voltage

Answer

Peak-to-peak voltage

Answer

Average voltage

Question 7

Which wire color in a standard NEC-compliant 120V residential wiring system is the grounded conductor (neutral)?

Accepted Answer

White

Answer

Black

Answer

Red

Answer

Green