Furnace Operation Quiz

What happens when the thermostat reaches a set temperature or is turned up by the homeowner?

• The gas valve opens

• The furnace ignitor glows

• The thermostat sends a signal for the furnace to turn on

• The blower motor starts

What voltage should you measure between W and C on the control board during the safety check?

• 12 volts AC

• 24 volts AC

• 110 volts AC

• 125 volts AC

What is the function of the inducer motor in the furnace operation sequence?

• To open the gas valve

• To create a vacuum to ensure leftover gases go out the exhaust pipe

• To ignite the furnace

• To start the blower motor

What happens if the pressure switch does not close?

• The gas valve opens

• The furnace ignitor glows

• The inducer motor stops

• The furnace will not proceed to the next step

What should the furnace ignitor do when the control board sends power to it?

• Open the gas valve

• Start the blower motor

• Glow bright orange

• Close the pressure switch

What ensures proper combustion in the furnace?

• The blower motor

• The gas valve opening and combining gas with air

• The furnace ignitor

• The pressure switch closing

What will the flame sensor do if the gas burners do not ignite within 5 to 8 seconds?

• Keep the gas valve open

• Turn the ignition source off

• Start the blower motor

• Close the pressure switch

What happens after a pre-determined amount of time when the blower motor starts?

• The gas valve opens

• The furnace ignitor glows

• Air is passed over the system's heat exchangers to provide heated air

• The thermostat sends a signal for the furnace to turn on

What happens when the thermostat on the wall satisfies the need for heat?

• The gas valve opens

• The blower motor starts

• The voltage in the W wire is broken and the gas burners are cut off

• The furnace ignitor glows

What does the furnace blower motor do after the heat is removed from the furnace's heat exchanger?

• It continues to run for a set amount of time

• It shuts down immediately

• It starts the furnace ignitor

• It opens the gas valve