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You are checking for proper airflow in CFM on a three ton heat pump system. The system has one return grill measuring 24" x 24", which has a net free area of 3.5 square feet. You measure air velocity and calculate an average of 243 FPM. What can you conclude from this information?

User Gnos
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1 Answer

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Final answer:

The airflow in CFM calculated for a three ton heat pump system is 850.5 CFM, which is below the typical requirement of 1200 CFM. This indicates a shortfall in airflow potentially affecting the system's efficiency.

Step-by-step explanation:

To assess proper airflow in CFM for a three ton heat pump system, we need to calculate the cubic feet per minute (CFM) of air movement through the return grill. The information provided states that the return grill is 24 inches by 24 inches with a net free area of 3.5 square feet and that the average air velocity is 243 feet per minute (FPM).

To calculate the CFM, you multiply the area in square feet by the velocity in feet per minute:

CFM = Area (sq ft) × Velocity (FPM)

Therefore:

CFM = 3.5 sq ft × 243 FPM = 850.5 CFM

A three ton heat pump typically requires about 1200 CFM for efficient operation. From our calculation, we observe that the system is experiencing a shortfall in airflow as the measured CFM is below the required CFM for a three ton system. This implies that airflow efficiency may be inadequate for optimal performance of the heat pump system.

User Ali Motevallian
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