HVAC Review Questions and Answers
| Latest Version | 2025/2026 | Correct &
Verified
What is the function of a centrifugal pump in HVAC systems?
✔✔To move water or other fluids through a piping system.
What does the term “enthalpy” represent in thermodynamics?
✔✔The total heat content of a system, including internal energy and flow work.
What is the primary function of a cooling tower?
✔✔To reject heat from water-cooled systems into the atmosphere.
What is the difference between a chiller and a heat pump?
✔✔A chiller removes heat for cooling, while a heat pump can provide both heating and cooling.
Why is airflow measurement important in duct systems?
✔✔To ensure proper ventilation and efficient system operation.
What is the role of a coil in an HVAC system?
✔✔To transfer heat between air and a refrigerant or water.
What is the purpose of a variable air volume (VAV) system?
1
,✔✔To adjust airflow to maintain zone temperature efficiently.
What is superheat in refrigeration systems?
✔✔The temperature of refrigerant vapor above its boiling point at a given pressure.
What is subcooling in a refrigeration system?
✔✔The temperature of refrigerant liquid below its condensation point at a given pressure.
Why is insulation used on HVAC piping?
✔✔To reduce heat loss or gain and prevent condensation.
What is the purpose of an expansion tank in a hydronic system?
✔✔To accommodate water expansion and maintain system pressure.
What is the function of a condenser in a refrigeration cycle?
✔✔To release heat from the refrigerant to the surroundings.
What is a common method to control humidity in HVAC systems?
✔✔Using cooling coils to condense moisture or adding humidification equipment.
Why is refrigerant charge critical in air conditioning systems?
✔✔To ensure efficient operation and prevent compressor damage.
2
, What is the purpose of a duct damper?
✔✔To regulate or redirect airflow within ductwork.
What is a heat exchanger?
✔✔A device that transfers heat between two fluids without mixing them.
Why is air filtration important in HVAC systems?
✔✔To improve indoor air quality and protect equipment.
What is the function of a blower fan in a furnace?
✔✔To circulate air through ductwork and across heating or cooling coils.
What is the purpose of a pressure relief valve in a hydronic system?
✔✔To protect the system from excessive pressure.
What does COP (Coefficient of Performance) measure in HVAC systems?
✔✔The efficiency of heating or cooling equipment.
Why is refrigerant oil necessary in a compressor?
✔✔To lubricate moving parts and ensure proper operation.
3
| Latest Version | 2025/2026 | Correct &
Verified
What is the function of a centrifugal pump in HVAC systems?
✔✔To move water or other fluids through a piping system.
What does the term “enthalpy” represent in thermodynamics?
✔✔The total heat content of a system, including internal energy and flow work.
What is the primary function of a cooling tower?
✔✔To reject heat from water-cooled systems into the atmosphere.
What is the difference between a chiller and a heat pump?
✔✔A chiller removes heat for cooling, while a heat pump can provide both heating and cooling.
Why is airflow measurement important in duct systems?
✔✔To ensure proper ventilation and efficient system operation.
What is the role of a coil in an HVAC system?
✔✔To transfer heat between air and a refrigerant or water.
What is the purpose of a variable air volume (VAV) system?
1
,✔✔To adjust airflow to maintain zone temperature efficiently.
What is superheat in refrigeration systems?
✔✔The temperature of refrigerant vapor above its boiling point at a given pressure.
What is subcooling in a refrigeration system?
✔✔The temperature of refrigerant liquid below its condensation point at a given pressure.
Why is insulation used on HVAC piping?
✔✔To reduce heat loss or gain and prevent condensation.
What is the purpose of an expansion tank in a hydronic system?
✔✔To accommodate water expansion and maintain system pressure.
What is the function of a condenser in a refrigeration cycle?
✔✔To release heat from the refrigerant to the surroundings.
What is a common method to control humidity in HVAC systems?
✔✔Using cooling coils to condense moisture or adding humidification equipment.
Why is refrigerant charge critical in air conditioning systems?
✔✔To ensure efficient operation and prevent compressor damage.
2
, What is the purpose of a duct damper?
✔✔To regulate or redirect airflow within ductwork.
What is a heat exchanger?
✔✔A device that transfers heat between two fluids without mixing them.
Why is air filtration important in HVAC systems?
✔✔To improve indoor air quality and protect equipment.
What is the function of a blower fan in a furnace?
✔✔To circulate air through ductwork and across heating or cooling coils.
What is the purpose of a pressure relief valve in a hydronic system?
✔✔To protect the system from excessive pressure.
What does COP (Coefficient of Performance) measure in HVAC systems?
✔✔The efficiency of heating or cooling equipment.
Why is refrigerant oil necessary in a compressor?
✔✔To lubricate moving parts and ensure proper operation.
3
