Forced Air Heating Systems

What is the primary medium used in forced-air heating systems to transfer heat?

Air

What are the key components of forced-air heating systems?

Heat source with heat exchanger, blower, ducts, and controls.

What are the common heat sources for furnaces?

Gas burners, electric resistance coils, and oil burners.

What is the function of the burner vestibule in a furnace?

It houses the burner(s) and controls, allowing combustion air to flow to the burners.

What are the three configurations of furnaces based on air flow?

Upflow, horizontal, and downflow (counterflow).

What components make up the air distribution system in forced-air heating?

Supply ducts and registers, return ducts and grilles, and filters.

What is the goal of an air distribution system?

Efficient air delivery and consistent temperature throughout the building.

What types of blowers are used in forced-air heating systems?

Propeller fans, centrifugal blowers, and axial-flow blowers.

What role does the thermostat play in a forced-air heating system?

It controls when the heat turns on and off.

What is the purpose of a limit switch in heating systems?

To prevent overheating.

How does a gas fuel-fired atmospheric burner ignite the air-fuel mixture?

By a pilot burner or an electric spark igniter.

What is the function of a combination valve in a gas furnace?

It controls the flow of gas fuel to the main burner and the pilot burner.

What type of heating elements are used in electric furnaces?

Resistance heating elements.

What is the function of filters in forced-air heating systems?

To remove particulate matter from the air.

What are registers and how do they function in heating systems?

Registers consist of a panel with vanes and a damper for controlling airflow, throwing air straight out or spreading it evenly.

What is a unit heater?

A self-contained heating unit that is not connected to ductwork.

What distinguishes a duct heater from other heating units?

It is located inside ductwork and uses air from a remote blower.

What is a direct-fired heater?

A unit heater that does not have a heat exchanger.

What is the purpose of troubleshooting matrices in forced-air heating systems?

They assist in diagnosing issues within the systems.

What type of units provide heating and cooling from the roof of a building?

Rooftop packaged units.

What is the function of overload relays in heating systems?

They shut a motor off if it overheats.

What is the role of variable frequency drives (VFDs) in modern blower systems?

To enhance efficiency and comfort by controlling motor speed.