Heating, Ventilation, & Air Conditioning (HVAC) Inspection Flashcards

A home inspector observes that a gas furnace has a cracked heat exchanger. Why is this a critical safety defect?

Answer: It can allow carbon monoxide to mix with conditioned air circulated throughout the home

A cracked heat exchanger can allow combustion gases, including deadly carbon monoxide, to enter the air distribution system and be circulated throughout the living space.

What does the SEER rating measure on an air conditioning system?

Answer: Seasonal Energy Efficiency Ratio — cooling output divided by energy input over an entire cooling season

SEER (Seasonal Energy Efficiency Ratio) measures the total cooling output over a typical cooling season divided by the total electrical energy input, with higher numbers indicating greater efficiency.

When inspecting ductwork, which condition indicates a significant problem that should be reported?

Answer: Disconnected or separated duct sections in unconditioned spaces

Disconnected or separated ducts in unconditioned spaces such as attics or crawlspaces cause conditioned air to be delivered outside the living area, significantly reducing system efficiency and potentially creating moisture problems.

A radiant floor heating system inspector notices that one zone does not heat up while others function normally. What is the MOST likely cause?

Answer: A failed zone valve or circuit issue for that specific loop

When only one zone fails to heat in a radiant system, the most likely cause is a failed zone valve or an air lock/blockage in that specific hydronic loop, since other zones are operating normally.

What is the purpose of a combustion air intake on a high-efficiency (condensing) furnace?

Answer: To supply outside air directly to the burner for combustion, avoiding depressurization of the home

A dedicated combustion air intake draws outside air directly to the burner, preventing the furnace from depressurizing the home and potentially causing backdrafting of other combustion appliances.

When inspecting a central air conditioning system, the inspector notices ice forming on the refrigerant suction line near the air handler. What does this indicate?

Answer: Restricted airflow or low refrigerant charge causing the evaporator to freeze

Ice on the suction line indicates the evaporator coil is freezing due to restricted airflow (dirty filter or coil) or low refrigerant charge, both of which cause the refrigerant temperature to drop below freezing.

A home inspector is evaluating a whole-house humidifier attached to the furnace. Which defect is MOST important to report?

Answer: The humidifier water supply line shows signs of active leaking onto the furnace

An active water leak from the humidifier supply line can cause water damage to the furnace, surrounding structure, and create conditions favorable for mold growth.