Certified Energy Auditor Certification Certified Energy Auditor HVAC Systems and Performance Questions and Answers 2 — Questions and Answers
Question 1: What is the primary purpose of measuring static pressure in an HVAC duct system during an energy audit?
- To determine airflow resistance and identify duct restrictions (Correct answer)
- To calculate the refrigerant charge level
- To measure indoor humidity levels
- To assess the electrical load of the blower motor
Correct answer: To determine airflow resistance and identify duct restrictions
Static pressure measurements reveal airflow resistance caused by dirty filters, undersized ducts, or blocked dampers that force the system to work harder.
Question 2: Which metric best indicates the seasonal cooling efficiency of a central air conditioning system?
- AFUE
- SEER (Correct answer)
- COP at peak load
- Supply air temperature
Correct answer: SEER
SEER (Seasonal Energy Efficiency Ratio) measures cooling output divided by electrical input over an entire cooling season.
Question 3: During a combustion efficiency test on a gas furnace, a high concentration of carbon monoxide in the flue gas most likely indicates what condition?
- Excess combustion air
- Incomplete combustion due to insufficient air or burner problems (Correct answer)
- A cracked heat exchanger allowing conditioned air into the flue
- Over-fired gas valve with too much fuel pressure
Correct answer: Incomplete combustion due to insufficient air or burner problems
Elevated CO in flue gases signals incomplete combustion, typically caused by inadequate combustion air, dirty burners, or improper gas-air mixing.
Question 4: What is the recommended minimum outdoor air ventilation standard that energy auditors reference for commercial HVAC systems in the United States?
- ASHRAE Standard 62.1 (Correct answer)
- ASHRAE Standard 90.1
- EPA Indoor airPLUS
- ICC International Mechanical Code Chapter 1
Correct answer: ASHRAE Standard 62.1
ASHRAE Standard 62.1 establishes minimum ventilation rates and indoor air quality requirements for commercial buildings.
Question 5: An energy auditor finds that a rooftop unit's economizer dampers remain fully closed during mild outdoor conditions when free cooling should be available. What is the most likely cause?
- The compressor is short-cycling on high pressure
- The outdoor air temperature sensor or economizer controller has failed (Correct answer)
- The condensate drain is clogged
- The supply fan VFD is operating at minimum speed
Correct answer: The outdoor air temperature sensor or economizer controller has failed
A failed outdoor air sensor or economizer controller prevents the system from recognizing favorable conditions for free cooling.
Question 6: What does a low superheat reading at the evaporator coil of a direct-expansion cooling system typically indicate?
- The system is overcharged or the expansion valve is feeding too much refrigerant (Correct answer)
- The condenser coil is dirty and needs cleaning
- The compressor is losing capacity due to worn valves
- The air filter is excessively dirty reducing airflow
Correct answer: The system is overcharged or the expansion valve is feeding too much refrigerant
Low superheat means liquid refrigerant is not fully evaporating, indicating overcharging or an expansion valve feeding excess refrigerant.
Certified Energy Auditor Certification Certified Energy Auditor HVAC Systems and Performance Questions and Answers 2
What is the primary purpose of measuring static pressure in an HVAC duct system during an energy audit?