Which statement best describes the function of the supply blower?

Which statement best describes the function of the supply blower?

• A. Delivers conditioned air to living spaces; ducts must be sized to match the statics pressure capability of the supply blower being used
• B. Filters outdoor air
• C. Circulates air within the equipment room only
• D. Expels air to outdoors

Answer: (A)

The supply blower’s job is to push conditioned air through the duct system and out to the living spaces. To do this effectively, the ducts must be sized to match the blower’s static pressure capability. Static pressure is the resistance the duct network presents to airflow; the blower has to overcome that resistance to deliver the desired amount of air. If the ducts are too restrictive for the blower, airflow at the vents drops because the blower hits its pressure limit. If the ducts are oversized, the blower can still move air, but efficiency and delivery at the outlets aren’t optimized—the key is balancing the blower’s pressure capability with the duct design to achieve the required airflow. The other statements aren’t describing the blower’s function: filtering outdoor air is typically handled by filters in the air path (not the blower itself), circulating air only within the equipment room isn’t the blower’s purpose, and expelling air outdoors is an exhaust function, not supplying conditioned air to living spaces.

The supply blower’s job is to push conditioned air through the duct system and out to the living spaces. To do this effectively, the ducts must be sized to match the blower’s static pressure capability. Static pressure is the resistance the duct network presents to airflow; the blower has to overcome that resistance to deliver the desired amount of air. If the ducts are too restrictive for the blower, airflow at the vents drops because the blower hits its pressure limit. If the ducts are oversized, the blower can still move air, but efficiency and delivery at the outlets aren’t optimized—the key is balancing the blower’s pressure capability with the duct design to achieve the required airflow.

The other statements aren’t describing the blower’s function: filtering outdoor air is typically handled by filters in the air path (not the blower itself), circulating air only within the equipment room isn’t the blower’s purpose, and expelling air outdoors is an exhaust function, not supplying conditioned air to living spaces.