Where must the draft control device be installed if the location is not specified by the appliance manufacturer’s instructions?

• A. On the floor near the appliance
• B. On the roof
• C. Inside the living space
• D. Attached to the flue collar of the equipment or as near to the equipment as practical

Answer: (D)

Draft control devices regulate the flow of flue gases to keep venting safe and reliable. When the manufacturer doesn’t specify a location, install the draft control as close to the appliance as practical, typically attached to the flue collar. Placing it near the equipment ensures the control senses the actual draft generated by that appliance and can respond quickly to changes, keeping combustion safe and preventing backdraft or spillage.

Attaching the device to the flue collar is preferred because it places the sensing point right at the source of the exhaust, where drafts are most representative of the system’s operating conditions. Installing it on the floor, on the roof, or inside the living space would subject it to unrelated air currents or conditions away from the appliance, making the control less accurate and potentially unsafe.