BAP BAP Combustion & Mechanical Systems 1 — Questions and Answers
Question 1: What is the primary purpose of a combustion analyzer in a building analyst's assessment?
- To measure flue gas composition and efficiency of combustion appliances (Correct answer)
- To detect carbon monoxide in living spaces only
- To measure natural gas pressure at the meter
- To test electrical continuity in HVAC controls
Correct answer: To measure flue gas composition and efficiency of combustion appliances
A combustion analyzer measures flue gas constituents such as O2, CO, and CO2 to calculate appliance efficiency and identify unsafe combustion conditions.
Question 2: Which condition most commonly causes a gas furnace to produce elevated carbon monoxide (CO) levels?
- Oversized supply ducts
- Incomplete combustion due to improper air-to-fuel ratio (Correct answer)
- High static pressure in the return plenum
- Refrigerant leaks in the air handler
Correct answer: Incomplete combustion due to improper air-to-fuel ratio
Incomplete combustion, often caused by insufficient combustion air or a cracked heat exchanger, is the primary source of elevated CO in gas furnaces.
Question 3: What does a steady CO reading of 400 ppm in a furnace's flue gases indicate to a BAP analyst?
- Normal combustion conditions for an older unit
- A potentially hazardous combustion problem requiring immediate action (Correct answer)
- Low natural gas pressure at the appliance
- A dirty air filter restricting return airflow
Correct answer: A potentially hazardous combustion problem requiring immediate action
400 ppm CO in flue gases signals seriously incomplete combustion; BPI standards require the analyst to shut down the appliance and notify the client.
Question 4: What is the purpose of a spillage test on a naturally drafted combustion appliance?
- To verify the gas valve opens fully under load
- To confirm combustion gases are venting properly and not spilling into the living space (Correct answer)
- To measure the BTU output at the burner
- To check for refrigerant leaks near the flue collar
Correct answer: To confirm combustion gases are venting properly and not spilling into the living space
A spillage test, typically performed with a smoke pencil or mirror, confirms that flue gases draft correctly up the vent rather than spilling into conditioned space.
Question 5: Which test is used to determine whether a combustion appliance zone (CAZ) has enough air for safe combustion and venting?
- Blower door depressurization of the CAZ (Correct answer)
- Duct leakage to outside test
- Infrared scan of the heat exchanger
- Manometer reading at the gas meter
Correct answer: Blower door depressurization of the CAZ
A CAZ depressurization test uses a blower door to simulate worst-case house pressures and determine if backdrafting of combustion appliances can occur.
Question 6: What is the BPI maximum allowable ambient CO level in a combustion appliance zone before work should stop?
- 9 ppm
- 35 ppm (Correct answer)
- 70 ppm
- 100 ppm
Correct answer: 35 ppm
BPI protocols require analysts to stop work and evacuate if ambient CO in the CAZ reaches or exceeds 35 ppm, following OSHA/EPA safety thresholds.
BAP BAP Combustion & Mechanical Systems 1
What is the primary purpose of a combustion analyzer in a building analyst's assessment?