Air Conditioning Repair Air Conditioning Repair Preventive Maintenance and System Efficiency 1 — Questions and Answers
Question 1: How often should air conditioning system air filters typically be inspected or replaced in a residential application?
- Every 1–3 months depending on usage and filter type (Correct answer)
- Once every 2 years
- Only when the system stops cooling
- At the time of installation only
Correct answer: Every 1–3 months depending on usage and filter type
Residential AC air filters should be inspected monthly and replaced every 1–3 months to maintain airflow and system efficiency.
Question 2: What is the recommended minimum coil cleaning frequency for a residential split-system AC under normal operating conditions?
- Once per year (Correct answer)
- Every 5 years
- Every 10 years
- Only when ice forms on the coil
Correct answer: Once per year
Evaporator and condenser coils should be cleaned at least once per year to prevent dirt buildup that reduces heat transfer.
Question 3: Which tool is used to measure refrigerant system pressures during a preventive maintenance check?
- Manifold gauge set (Correct answer)
- Megohmmeter
- Anemometer
- Psychrometer
Correct answer: Manifold gauge set
A manifold gauge set is used to measure both suction (low-side) and discharge (high-side) pressures during AC system servicing.
Question 4: What does a high delta-T (temperature difference) across the evaporator coil typically indicate?
- Good system performance with proper heat absorption (Correct answer)
- Low refrigerant charge
- Dirty condenser coil
- Overcharged refrigerant
Correct answer: Good system performance with proper heat absorption
A temperature difference of 16–22°F across the evaporator coil typically indicates the system is properly absorbing heat and operating efficiently.
Question 5: During a preventive maintenance visit, a technician finds the condenser fins are bent and partially blocking airflow. What is the correct action?
- Straighten the fins using a fin comb (Correct answer)
- Replace the entire condenser unit
- Add refrigerant to compensate for reduced efficiency
- Increase the thermostat set point
Correct answer: Straighten the fins using a fin comb
A fin comb is the proper tool to straighten bent condenser fins and restore airflow without damaging the coil.
Question 6: What is the purpose of checking and tightening electrical connections during preventive maintenance?
- To prevent resistance heating, arcing, and component failure (Correct answer)
- To increase system airflow
- To reduce refrigerant charge requirements
- To lower the superheat setting
Correct answer: To prevent resistance heating, arcing, and component failure
Loose electrical connections create resistance, generate heat, cause arcing, and can lead to component or control board failures.
Air Conditioning Repair Air Conditioning Repair Preventive Maintenance and System Efficiency 1
How often should air conditioning system air filters typically be inspected or replaced in a residential application?