What is a purge cycle in an air handling unit, and when is it typically used?

What is a purge cycle in an air handling unit, and when is it typically used?

• A. A brief purge of outdoor or stale air from the ductwork to refresh air; used during start-up, after occupancy changes, or in ventilation-only periods
• B. A continuous purge of indoor air during operation
• C. Purging only occurs during high humidity conditions
• D. Purging cycles are obsolete and not used

Answer: (A)