Damper

Damper


The main damper in the stack is used to control draft in the furnace. It is normal adjusted to achieve a negative 0.05 inches H2O pressure at the bridgewall. It is not used to control combustion air which is controlled by air plenum dampers or air registers at the burner(s). In the example used herein, it is used to redirect the flue gasses to the air preheat system.