Massachusetts Oil Burner License Practice Test

How can a damaged heat exchanger be identified in a forced warm air system?

1. By checking the thermostat settings

2. With a smoke trace candle

3. Through visual inspection only

4. Using a moisture meter

The correct answer is: With a smoke trace candle

A damaged heat exchanger in a forced warm air system can be identified effectively with a smoke trace candle. This method involves introducing smoke into the heat exchanger and observing if it escapes into the living space. A properly functioning heat exchanger should contain combustion gases within its structure, so any smoke that leaks out indicates a breach. This can be critical since such breaches can lead to dangerous carbon monoxide exposure. While other methods like visual inspection can reveal issues like rust or cracks, they may not detect all types of damage, especially those that are not immediately visible. Thermostat settings do not provide any information about the physical condition of the heat exchanger, and a moisture meter is designed to measure humidity levels rather than structural integrity. Therefore, using a smoke trace candle is a reliable way to diagnose potential leaks and ensure safe operation of the heating system.