Door heaters are designed for mounting directly over the door opening close to the wall. They should be installed with the coil side facing the inside of the building. This is important as these door heaters are recirulating heaters and should draw air from the inside of the building.

The centrifugal fans draw the air in a horizontal flow across the coil and then direct the heated air downward through the high velocity discharg outlet below the fans. The construction of the discharge permits varying the width of the air pattern by means of adjusting vanes.

If a high negative condition due to excessive exhaust systems exists in the building, no door heater or air curtain can prevent infiltration of “makeup air”. Properly selected, a high velocity door heater can effectively temper the incoming air by mixing it with hot discharge air. This prevents cold air from entering the work areas and maintains a balanced heating system.