CHI Heating, Ventilation, & Air Conditioning (HVAC) Inspection 3 — Questions and Answers
Question 1: Which type of filter has the highest MERV rating capability and provides the best filtration for an HVAC system?
- Fiberglass panel filters
- Pleated polyester filters
- Electrostatic filters
- HEPA filters (Correct answer)
Correct answer: HEPA filters
HEPA filters achieve MERV 17-20 ratings, capturing 99.97% of particles 0.3 microns and larger, making them the highest-efficiency option for HVAC systems.
Question 2: When inspecting a boiler system, what does a consistently high-pressure reading on the pressure gauge indicate?
- The system is operating at peak efficiency
- The expansion tank may be waterlogged or failed (Correct answer)
- The circulator pump is working correctly
- The boiler needs more water added
Correct answer: The expansion tank may be waterlogged or failed
Consistently high pressure in a boiler system typically indicates a waterlogged or failed expansion tank, which can no longer absorb pressure fluctuations as water expands when heated.
Question 3: What is the purpose of the flue gas spillage test performed near a draft hood on a natural draft furnace?
- To measure furnace efficiency rating
- To detect if combustion gases are backdrafting into the living area (Correct answer)
- To verify the thermocouple is functioning correctly
- To test igniter spark timing
Correct answer: To detect if combustion gases are backdrafting into the living area
A spillage test—typically using a match or smoke pencil near the draft hood—determines whether combustion gases are being properly exhausted or are spilling back into the living space.
Question 4: A home inspector observes rust staining and corrosion on the exterior of a central air conditioner's refrigerant line set insulation. What does this MOST likely indicate?
- Normal weathering with no functional concern
- Condensation forming due to damaged or missing insulation (Correct answer)
- High refrigerant charge causing exterior frost
- Pest damage from rodents nesting in the unit
Correct answer: Condensation forming due to damaged or missing insulation
Rust and corrosion on line set insulation typically indicates that the insulation is compromised, allowing condensation to form on the cold suction line and cause moisture damage.
Question 5: Which condition would require a home inspector to recommend evaluation of a ductless mini-split system by a qualified HVAC technician?
- The outdoor unit makes a brief clicking sound at startup
- Oil staining is visible around the refrigerant line connections at the outdoor unit (Correct answer)
- The system has two indoor heads connected to one outdoor unit
- The outdoor unit is mounted on a wall bracket rather than on the ground
Correct answer: Oil staining is visible around the refrigerant line connections at the outdoor unit
Oil staining around refrigerant line connections indicates a refrigerant leak, since refrigerant oil travels with the refrigerant and leaves visible residue at leak points.
Question 6: What is the function of a barometric damper (draft regulator) found on an oil-fired furnace flue?
- To increase draft by forcing more air into the combustion chamber
- To regulate draft by allowing dilution air to enter the flue when draft is excessive (Correct answer)
- To prevent backdrafting by sealing the flue when the burner is off
- To measure flue gas temperature for efficiency calculations
Correct answer: To regulate draft by allowing dilution air to enter the flue when draft is excessive
A barometric damper opens to admit room air into the flue when draft becomes too strong, maintaining a consistent, correct draft level for proper burner operation.
Question 7: During an HVAC inspection, the inspector notices the thermostat is set to 70°F but the system is not reaching that temperature on a mild day. What should the inspector check FIRST?
- Refrigerant charge level in the outdoor unit
- Air filter condition and return air restrictions (Correct answer)
- Condenser fan motor amperage draw
- Compressor capacitor voltage rating
Correct answer: Air filter condition and return air restrictions
A clogged air filter is one of the most common causes of HVAC performance issues and should always be checked first before investigating mechanical components.
CHI Heating, Ventilation, & Air Conditioning (HVAC) Inspection 3
Which type of filter has the highest MERV rating capability and provides the best filtration for an HVAC system?