Home Inspector Forced-Air Furnace Inspection Questions and Answers

Question 1

While inspecting a gas-fired, forced-air furnace, a home inspector observes a consistently yellow, wavering flame at the burners. Which of the following is the MOST likely cause of this condition?

Accepted Answer

Inadequate combustion air

Answer

A cracked heat exchanger

Answer

Improper gas pressure

Answer

A malfunctioning gas valve

Question 2

A home inspector is evaluating a conventional metal flue vent pipe for a gas furnace and notices white, chalky residue and faint streaks on the exterior of the pipe joints. This observation is most indicative of which of the following problems?

Accepted Answer

Condensation and poor drafting of exhaust gases

Answer

Normal oxidation of the galvanized metal

Answer

Excessive heat from the furnace

Answer

A blocked or partially obstructed flue

Question 3

During a furnace inspection, you identify a crack in the heat exchanger. What is the PRIMARY safety concern associated with this defect?

Accepted Answer

The leakage of combustion gases, like carbon monoxide, into the conditioned air

Answer

Reduced heating efficiency and higher utility bills

Answer

The potential for fire within the furnace cabinet

Answer

Damage to the blower motor from excessive heat

Question 4

Which of the following furnace components is a safety device designed to shut down the burners if the temperature in the plenum becomes excessively high, preventing damage to the heat exchanger?

Accepted Answer

High-limit switch

Answer

Flame rollout switch

Answer

Pressure switch

Answer

Gas valve

Question 5

A home inspector observes significant rust and corrosion on the exterior of a furnace's heat exchanger. This condition is MOST likely an indicator of:

Accepted Answer

Past or present condensation issues

Answer

A refrigerant leak from the evaporator coil

Answer

High humidity in the utility room

Answer

Normal aging on a furnace older than 10 years

Question 6

When inspecting a forced-air furnace system, an inspector notes that the metal flue pipe has a horizontal run of 8 feet before it enters the chimney. For proper drafting of exhaust gases, this horizontal pipe should:

Accepted Answer

Have a continuous upward slope towards the chimney

Answer

Be perfectly level to ensure even flow

Answer

Have a downward slope away from the chimney

Answer

Be insulated to maintain high gas velocity

While inspecting a gas-fired, forced-air furnace, a home inspector observes a consistently yellow, wavering flame at the burners.Which of the following is the MOST likely cause of this condition?

While inspecting a gas-fired, forced-air furnace, a home inspector observes a consistently yellow, wavering flame at the burners.
Which of the following is the MOST likely cause of this condition?