Automatic Combustion Air Dampers

Most building codes require that outside air be provided for the ventilation of boiler and furnace rooms. Fixed or manually-operated combustion air dampers can allow cold winter air into the room even when burners are not operating. By installing automatic combustion air dampers, which only open when the burners are operating, exposure of the boiler and piping to cold outside air is reduced. This reduces heat loss, which saves you money.

Both the manual and the automatic combustion air dampers are effective in providing outside air, but the manual mode is far less energy efficient. With a manually operated damper, the opening is almost always left open, letting in cold air. The result is that heating equipment is cooled and equipment energy efficiencies are reduced. With an automatic damper, the opening is closed when the burner is off and is opened just before it comes on. The system should be set up so that the damper opens before the burner can operate.

Installing an automatic damper many require making changes in ductwork which must follow building codes. Check with your local building inspector on code compliance and hire a qualified mechanical contractor or electrician to do the installation.

Weatherstripping an existing or new combustion air damper is easy and cost effective. There are several products which can be used for the weatherstripping . One inexpensive type consists of vinyl edges, which can be attached to the damper blades with glue or other type of adhesive. Felt weatherstripping is not recommended because it wears out very quickly. Note: Should the installation of weatherstripping require disassembly of the damper, don't attempt to do it yourself; contact a mechanical contractor.