To check air delivery and balancing of an air conditioning system, you would use which instrument?

• A. Velometer
• B. Manometer
• C. Anemometer
• D. Thermometer

Answer: (A)

Measuring how fast air is moving through the ducts is key to verifying how much air is actually delivered to each area. A velometer is designed to measure the velocity of air in ductwork and at diffusers, which lets you calculate the airflow (CFM) when you know the duct area. By taking readings at multiple outlets and comparing them to design values, you can adjust dampers to achieve proper balance across the system.

Other instruments don’t directly measure the delivery flow for balancing: a manometer checks pressure differences, which helps diagnose losses; an anemometer also measures air velocity but is more general and not as specifically tied to duct balancing; a thermometer measures temperature.