Practice Test Geeks(HERS) Certified Home Energy Rating System Rater Practice Test
← All HERS Flashcard Decks

Combustion Safety Flashcards

7 cards from real HERS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Combustion Safety flashcards as text

  1. A HERS rater tests a home with a gas range and finds elevated CO in the kitchen. What is the most likely cause if only the range top burners are running normally?

    Answer: Incomplete combustion at the range burner due to improper air-fuel mixture or dirty burner

    Gas range burners with improper air-fuel ratios or partially blocked burner ports produce elevated CO due to incomplete combustion even during normal operation.

  2. Which of the following best describes the hazard of a cracked heat exchanger in a forced-air gas furnace?

    Answer: Combustion gases including CO can mix with and be distributed through supply air throughout the home

    A cracked heat exchanger allows combustion gases to cross into the supply airstream, distributing CO and other combustion byproducts to every room served by the duct system.

  3. What safety device is required by most codes in sleeping areas and on each level of a home to protect against CO poisoning?

    Answer: CO alarm

    CO alarms are required on each level of a home and outside sleeping areas to provide early warning of dangerous CO concentrations from combustion appliances.

  4. During a worst-case CAZ test, which exhaust device typically contributes the most depressurization?

    Answer: Range hood (400+ CFM)

    Large range hoods with high CFM ratings typically dominate CAZ depressurization because they exhaust far more air than bathroom fans or dryers.

  5. A home has been air-sealed and tightened significantly. What combustion safety issue may arise if no other changes were made?

    Answer: Reduced infiltration may starve atmospheric appliances of combustion air, increasing backdrafting risk

    Air sealing reduces the infiltration that previously supplied combustion air to atmospheric appliances, potentially increasing depressurization and backdrafting risk.

  6. What is the correct procedure if a HERS rater discovers steady-state CO spillage from a water heater draft hood during testing?

    Answer: Immediately shut down the appliance and advise the homeowner not to use it until repaired

    Steady-state spillage is an immediate health and safety hazard; the appliance must be shut down and the homeowner advised not to use it until a qualified technician performs repairs.

  7. Which type of gas appliance venting is most resistant to changes in house pressure conditions?

    Answer: Sealed-combustion (direct-vent) appliance

    Sealed-combustion direct-vent appliances draw combustion air from and exhaust directly to the outdoors through dedicated pipes, making them completely unaffected by indoor pressure changes.