HVAC - Heating, Ventilation, and Air Conditioning Heating Systems 1

Question 1

What does the Annual Fuel Utilization Efficiency (AFUE) rating measure in a gas furnace?

Accepted Answer

The percentage of fuel energy converted to usable heat over a heating season

Answer

The ratio of heat output to electrical energy consumed

Answer

The maximum BTU output the furnace can produce

Answer

The rate at which the furnace cycles on and off per hour

Question 2

Which type of heating system uses water heated by a boiler and distributed through pipes to radiators or radiant floor tubing?

Accepted Answer

Hydronic system

Answer

Forced-air system

Answer

Heat pump system

Answer

Gravity furnace system

Question 3

What is the primary purpose of a heat exchanger in a gas furnace?

Accepted Answer

To separate combustion gases from the air distributed to the living space

Answer

To regulate the gas pressure entering the burner

Answer

To ignite the gas burner during startup

Answer

To control the speed of the blower motor

Question 4

In a hot water boiler system, what is the function of an expansion tank?

Accepted Answer

To accommodate the volume increase of water as it heats and expands

Answer

To store extra fuel for the burner during peak demand

Answer

To increase water pressure when demand is high

Answer

To filter sediment from the return water before it re-enters the boiler

Question 5

What type of ignition system has largely replaced standing pilot lights in modern gas furnaces?

Accepted Answer

Electronic spark or hot surface ignition

Answer

Piezoelectric ignition

Answer

Thermocouple ignition

Answer

Glow plug ignition

Question 6

What is the purpose of a modulating gas valve in a high-efficiency furnace?

Accepted Answer

To vary the gas flow rate so the furnace can operate at partial capacity to match heating demand

Answer

To shut off gas flow immediately if a flame failure is detected

Answer

To regulate gas pressure from the utility supply to burner pressure

Answer

To allow the furnace to switch between natural gas and propane fuels