Direct-Fired Systems

Flexible units for space heating, make-up air, and ventilation applications

Gas Burner Section

Factory set and tested to ETL standards for 100% efficiency.

Gas Manifold

Completely factory assembled and tested.

Optional Intake Hood

For outdoor models (DFC, DFL), Applied Air offers a complete matching intake hood.

Filter

Optional filter module keeps out bugs and helps minimize accumulation of dust, dirt, and airborne particles in the space.

Access Doors

Full size doors provide easy access to fan, burner, and controls. Access doors are hinged and use industrial grade fasteners.

Blowers

Direct Fired units feature centrifugal blowers tested to AMCA standards and motors with adjustable bases.

When more air is exhausted from a building than is supplied by the mechanical systems, the building is under a "negative" condition and air will leak into the building through cracks, windows and doors. A negative condition results in the following:

• Flues and stacks will experience a backdraft and cause dangerous contaminants to remain in the occupied space. In the case of flues, the products of combustion may condense and corrode the equipment.
• The exhaust system sees a greater static pressure which reduces the capacity of each fan, resulting in an inadequate removal of contaminants and wasted horsepower.
• Drafts and cross currents will increase, causing an uncomfortable or unhealthy work environment.

Direct Firing eliminates the need for heat exchangers, resulting in 100% efficiency. All products of combustion are introduced into the supply air stream at concentrations well below code requirements. As natural gas is an abundant, clean and low cost fuel that is readily available, this system is very cost effective to operate.

How Direct Fired Gas Heating Works

Direct Fired gas heating is one of the simplest and most cost-effective methods for heating air. Outside air enters the unit (at point C) and is either filtered or not. If desired, a quantity of returning room air can be added (B) to this outside air in a balanced fashion to assure a constant total airflow. This air then passes over a line burner: The airflow pattern is closely controlled using profile plates, resulting in 100% efficient combustion.

The air is directly heated by this clean, controlled gas flame and distributed into the building using heavy duty centrifugal blowers (G). By carefully controlling the airflow pattern and volume, the system can provide complete, 100% combustion. Complete combustion produces only water vapor and carbon dioxide (CO2). Harmful combustion by-products are the result of incomplete combustion and a good reason why you should buy from an established expert in gas heating technology.

Features and Benefits of Direct Fired Gas Heating

• The heavy gauge galvanized steel outer panels are designed to eliminate rust for longer life.
• Blowers tested to AMCA standards assure proper airflow for efficient operation.
• The ETL approved, single speed, natural gas fired unit offers adjustable burner profile plates and control system for modulation down to 4% of full input. This delivers the precise amount of gas to the burner, maintaining the exact temperature setting with the lowest possible gas usage.
• The 140 point final test procedure for every Applied Air Direct Fired unit means fewer start-up problems.
• For maximum flexibility, units can be installed indoors or outdoors, vertically or horizontally, or include evaporative cooling modules.
• Direct Fired units are 100% efficient.