When does an electrically operated automatic vent damper on a mid-efficiency furnace open?

An electrically operated automatic vent damper on a mid-efficiency furnace is designed to optimize the combustion and venting process by ensuring that proper airflow is achieved before ignition occurs. When the vent damper opens before the ignition cycle, it allows fresh air to flow through the furnace's combustion chamber, which is essential for efficient combustion of the gas once the ignition sequence commences.

This pre-ignition opening helps to create the necessary conditions for the furnace to operate safely and efficiently, minimizing the risk of backdrafts or incomplete combustion. Proper venting establishes a draft, which is crucial in ensuring that flue gases are expelled appropriately during operation.

The timing of the damper opening is critical for safe operation, as it allows the system to function effectively without creating hazardous conditions.