Residential HVAC Installation Practice Exam

What is the purpose of an auxiliary drain pan when the evaporator is installed above the conditioned space?

1. A. To increase airflow

2. B. To improve energy efficiency

3. C. To prevent water damage

4. D. To reduce noise

The correct answer is: C. To prevent water damage

The purpose of an auxiliary drain pan is to prevent water damage in the event of a leak in the primary drain pan. An auxiliary drain pan is necessary when the evaporator is located above the conditioned space because any potential leak would cause water to drip into the living area rather than the attic or crawlspace. Option A is incorrect because an auxiliary drain pan does not affect airflow in any way. Option B is incorrect because improving energy efficiency is not the purpose of an auxiliary drain pan. Option D is incorrect because reducing noise is not the purpose of an auxiliary drain pan.