Heating, Ventilation & Air Conditioning (HVAC) Flashcards
7 cards from real BPI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Heating, Ventilation & Air Conditioning (HVAC) flashcards as text
What is the primary risk of installing an oversized air conditioner in a humid climate?
Answer: Short cycling that prevents adequate dehumidification
An oversized AC cools the space quickly and shuts off before running long enough to remove sufficient moisture, leading to high indoor humidity despite comfortable temperatures.
When assessing duct leakage with a duct blower, what does 'duct leakage to outside' (CFM25-out) measure?
Answer: Leakage from ducts located outside the conditioned space only
CFM25-out measures only the leakage from ducts located outside the conditioned building envelope (e.g., attic, crawlspace ducts), which directly affects energy loss.
Which of the following best describes the role of the economizer in a commercial HVAC system?
Answer: Using outdoor air for free cooling when conditions are favorable
An economizer uses outdoor air for cooling when outdoor temperature and humidity are below set thresholds, reducing or eliminating mechanical cooling energy.
What is the recommended method to verify adequate combustion air supply for a naturally drafted appliance?
Answer: Perform a draft test with a manometer before and after closing interior doors
Measuring draft pressure before and after closing interior doors reveals whether the appliance loses adequate combustion air supply under realistic building conditions.
A homeowner's energy bills are high and the duct system is located in an unconditioned attic. What is the MOST impactful improvement?
Answer: Seal duct leaks and insulate ducts to at least R-8
Ducts in unconditioned attics lose substantial energy through both leakage and conduction; sealing leaks and adding R-8 insulation typically yields the greatest energy savings.
What does a negative reading on a manometer connected to measure appliance zone pressure indicate during a depressurization test?
Answer: The zone is depressurized relative to outdoors, increasing backdraft risk
A negative pressure reading in the appliance zone means that zone is depressurized relative to outside, which can cause backdrafting of combustion gases into the living space.
According to BPI, which ventilation strategy is considered most appropriate when tightening a leaky house?
Answer: Installing a continuous exhaust fan sized per ASHRAE 62.2
BPI requires that when a house is air-sealed, mechanical ventilation must be installed per ASHRAE 62.2 to maintain indoor air quality since natural infiltration can no longer be relied upon.