HVAC Flashcards
7 cards from real NHIE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 HVAC flashcards as text
What does the SEER rating measure on air conditioning equipment?
Answer: Seasonal Energy Efficiency Ratio — cooling output vs. electrical energy consumed over a season
SEER (Seasonal Energy Efficiency Ratio) measures total cooling output during a typical cooling season divided by total electrical energy consumed, with higher numbers indicating greater efficiency.
A home inspector observes an oil-fired boiler with the pressure gauge reading 30 PSI during operation. What should the inspector report?
Answer: This is high and potentially dangerous — normal operating pressure is 12-25 PSI
Hot-water boilers typically operate between 12-25 PSI; a reading of 30 PSI exceeds normal operating range and may indicate a failed pressure reducing valve or waterlogged expansion tank.
Which of the following is a common indication of a refrigerant leak in a central air conditioning system observed during a home inspection?
Answer: Ice formation on the evaporator coil and refrigerant lines
Ice forming on the evaporator coil and suction line indicates low refrigerant charge, which causes the coil to drop below freezing and freeze moisture from the air.
What type of filter has the highest MERV rating capability and most effective particulate removal?
Answer: HEPA filter
HEPA filters achieve MERV 17-20 equivalent ratings and remove 99.97% of particles 0.3 microns or larger, making them the most effective filtration option.
During inspection of a gas furnace, the inspector notices the pilot flame is yellow/orange rather than blue. What does this indicate?
Answer: Incomplete combustion, likely due to insufficient combustion air or a dirty burner
A yellow or orange pilot or burner flame indicates incomplete combustion, which can produce carbon monoxide and suggests insufficient air supply or contaminated burners.
An inspector finds that supply air registers in several rooms are not delivering airflow. The filter is clean and the blower is running. What should be checked next?
Answer: Dampers in the duct system that may be closed
Manual dampers inside duct branches can be closed, restricting or stopping airflow to specific zones, and should be checked when some rooms receive no air despite the system running.
What is the primary function of the metering device (expansion valve or orifice tube) in an air conditioning refrigeration circuit?
Answer: To reduce refrigerant pressure and temperature before it enters the evaporator coil
The metering device restricts refrigerant flow, causing a pressure drop that lowers the refrigerant temperature so it can absorb heat in the evaporator coil.