Massachusetts Oil Burner License Practice Test

If a second oil-burning appliance is installed in a single chimney, what must be ensured?

1. Flue size is increased

2. Isolation from the first appliance

3. Sufficient draft for safe operation

4. Electrical compatibility of appliances

The correct answer is: Sufficient draft for safe operation

When a second oil-burning appliance is installed in a single chimney, ensuring sufficient draft for safe operation is critical. The draft is the upward flow of gases through the chimney, which is necessary to expel combustion by-products effectively. If the chimney does not provide adequate draft, it can lead to backdrafting or the accumulation of dangerous fumes inside the building, which poses safety hazards. Proper calculation and evaluation are required to ensure that the combined flue gases from both appliances can be vented safely, maintaining the integrity of the system and the safety of those within the structure. In contrast, while increasing the flue size, isolating the appliances, and ensuring electrical compatibility may all be considerations in other contexts of appliance installation or operation, they do not directly address the fundamental necessity for adequate draft in a chimney servicing multiple appliances. Sufficient draft directly impacts the safety and efficiency of the appliances, making it the primary concern when adding another oil-burning unit to a shared chimney system.