Electricity Unit 13 review

Which of the following is an energy source for heat production in a warm-air furnace?

• Gas

• Oil

• Electricity

• All of the choices are correct

Which of the following choices best describes a limit switch used to detect flame roll-out on a gas furnace?

• Close on rise of pressure

• Close on rise of temperature

• Open on rise of temperature

• Differential temperature switch

Limit switches used in gas furnaces typically monitor the ______________________.

• Temperature within the air cavity of the furnace

• Temperature of the gasses in the flue pipe

• Temperature of the return air to the furnace

• Temperature of the blower motor

If the blower motor fails to start in a gas furnace, what device will prevent the internal temperature of the furnace from getting too high?

• Fan switch

• Limit switch

• Flame roll-out switch

• Vent pressure switch

What device is used on most newer furnaces to prove that the combustion blower is operating properly?

• Limit switch

• Pressure switch

• Roll-out switch

• Vent safety switch

The pressure switch on a typical gas furnace should close _____________________________.

• After the combustion blower starts

• Immediate when the thermostat calls for heat

• After the furnace shuts down

• Right after the burners ignite

A standing pilot is often classified as a(n) ____________________________.

• Intermittent ignition system

• Direct ignition system

• Continuous ignition system

• Electronic ignition system

What are the two most common methods of lighting the burners in a direct ignition system?

• Direct spark and hot surface ignition

• Direct spark and standing pilot ignition

• Hot surface and intermittent pilot ignition

• Standing pilot and intermittent pilot ignition

Which of the following gas furnace ignition systems uses a silicon carbide ignitor?

• Direct spark ignition

• Hot surface ignition

• Intermittent pilot ignition

• Continuous ignition systems

What will be the resulting operation of a gas furnace with a direct ignition system if the flame sensor is not positioned in the flame?

• The ignition control will not see the rectified pulsed DC signal from the flame

• The flame will not be sensed, and the ignition control will close the gas valve after each ignition trial period

• The ignition control will lock out after a set number of ignition trials

• All of the choices are correct