Home Inspector Forced-Air Furnace Inspection Flashcards
7 cards from real Home Inspector Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Home Inspector Forced-Air Furnace Inspection flashcards as text
A furnace located in a bedroom closet requires combustion air. What is the most common compliant solution for this confined space?
Answer: Using a sealed-combustion (direct-vent) appliance that draws combustion air from outside
A sealed-combustion furnace draws all combustion air directly from outdoors through a dedicated pipe, making it ideal for confined installations.
What is the purpose of a condensate neutralizer on a high-efficiency furnace?
Answer: To raise the pH of acidic condensate before it enters the drain system
Condensing furnace condensate is mildly acidic (pH 2.9–6.5) and can corrode drain lines; a neutralizer raises pH to acceptable levels before disposal.
During inspection, the inspector notices the furnace burners produce a lazy yellow or orange flame rather than a sharp blue flame. What does this indicate?
Answer: Incomplete combustion due to improper air-fuel mixture, possibly indicating a dirty burner or restricted air supply
A properly adjusted gas burner burns with a blue flame; yellow or orange flames indicate incomplete combustion, which can produce carbon monoxide.
Which of the following is the correct test method a home inspector uses to check for a cracked heat exchanger?
Answer: Observing flame behavior when the blower activates, listening for odors, and using a combustion gas analyzer
Home inspectors check for heat exchanger cracks by observing flame deflection when the blower starts, noting odors at registers, and using a combustion gas detector — not by disassembly.
A gas furnace is installed in a garage. Which additional safety requirement applies to this installation?
Answer: The furnace burner and ignition sources must be elevated at least 18 inches above the floor
In garages, furnaces must be elevated 18 inches above the floor to keep ignition sources above the level where gasoline vapors (which are heavier than air) can accumulate.
What does the term 'AFUE' stand for, and what does it measure?
Answer: Annual Fuel Utilization Efficiency — the percentage of fuel energy converted to heat
AFUE measures what percentage of fuel energy the furnace converts to usable heat over an entire heating season; a 95 AFUE furnace wastes only 5% of fuel.
An inspector finds the furnace vent connector passing through a combustible interior wall without a proper thimble or listed pass-through device. This is reported as:
Answer: A safety defect requiring correction before occupancy
Vent connectors passing through combustible walls require a listed thimble or pass-through device to maintain required clearances and prevent fire risk.