What diameter is specified for a Single Wall Vent Connector for a single appliance with an input of 1,000,000 BTUH and other defined factors?

For a single appliance with an input of 1,000,000 BTUH, the standard practice is to refer to the manufacturer's specifications and relevant codes, which often dictate the size of the vent connector needed for proper performance and safety. In the case of this input level, the correct diameter for a single wall vent connector is indeed 12 inches.

The size must be adequate to handle the flue gases produced by the appliance, ensuring that they can exit effectively while minimizing any risk of backdraft or inefficiency. The 12-inch diameter is a common requirement for appliances with high BTUH inputs because it balances the need for adequate airflow and reduces the risk of overheating or obstruction.

The other dimensions listed, while they may be relevant for other appliances or configurations, do not meet the requirements set for a 1,000,000 BTUH input appliance according to standard industry practices and codes. Therefore, selecting 12 inches is essential for ensuring safety and efficiency in the venting process.