Under what condition are two or more oil burning appliances allowed to connect to a single chimney?

The correct answer is based on the principle of ensuring proper draft in the chimney system. Adequate draft is crucial for the efficient and safe operation of any oil-burning appliance connected to a chimney. When two or more oil-burning appliances share a single chimney, the system must create enough upward airflow to properly vent combustion gases. This is essential to prevent backdrafts, which can lead to dangerous situations such as carbon monoxide buildup inside the home.

Factors like appliance type, BTU output, and the height and size of the chimney all influence whether or not the chimney can effectively handle multiple appliances. While there are many considerations when installing oil-burning appliances, ensuring that there is adequate draft is a fundamental requirement that safeguards both performance and safety.

In contrast, the other choices address unnecessary specifics, such as matching models or technician certification, which do not ensure the primary function of safe venting. While those factors may play a role in the installation process, they do not inherently guarantee that the chimney can manage multiple appliances effectively under the safety standards set forth by the Maine Journeyman Oil Fuel Board.