Two-stage or full modulation direct fired air make-up system designed for use on automotive spray booths. Damper in the system allows for multiple passes through the furnace resulting in higher temperature rise in the bake cycle.

The DFM800R is a direct fired air make-up system designed for use on automotive spray booths. Firing the heater directly into the air stream results in 98% efficiency, providing a rapid temperature rise in the spray booth.

Typically, this air make-up system uses the 700 series control panel for its control system.

Temperature stability is achieved by use of a two-stage burner. When the booth thermostat first signals for heat, the burner initially fires at the full 1,075,000 BTU/hr until the required temperature is reached, at which time it drops to LOW fire, approximately 60% of maximum. The temperature is then maintained by cycling between LOW fire and pilot fire. This bi-level heat system prevents shut-off of the burner which could allow cold air to be pumped into the booth.

Temperature stability is much, much more precisely controlled when the air make-up system is equipped with a full modulation burner. For comparison with the two-stage burner, think of high fire as 100, low fire as 60, and off or pilot flame only as 0 (zero); full modulation is all the numbers from 100 down to 0 (zero). Three steps to zero in the two-stage vs. 100 steps in the full modulation. Precision in the temperature control process allows for more temperature stability in the heating process. However, more temperature stability comes at a cost. Working of DFM800RThe full modulation burner is much more expensive than the two-stage modulation burner. For most automotive spray applications, the two-stage modulation is sufficient.

In order to achieve a higher temperature rise during the CURE cycle, a percentage of the incoming air is routed back past the burner before entering the booth. This proprietary process allows the temperature rise to take place much faster. This technique enables the DFM800R to achieve a temperature rise of 160 degrees Fahrenheit over an outside ambient temperature of 0 degree Fahrenheit. However, the integrity of the system is maintained by superheating only the clean air entering the booth. Competitive designs recycle a portion of the air removed from the booth which contains dirt and solvents. This results in hazing or die-back of the finish and requires cutting and buffing to achieve a good finish. By using only fresh air in our superheating process, AFC has eliminated or minimized this extra work.

The DFM800R is constructed of 18 gauge galvanized steel for strength and durability and is designed to be weather-proof so it can be mounted on the roof of the building as well as the standard roof of the booth. Shown above is the vertically floor mounted configuration. It is also adaptable for use on the REVERSED Aire-Flo booths as well as custom installation on other booths.

For the larger truck booths, AFC supplies the DFM2000, with a two million BTU/hr burner.

Drawings of standard variation of the DFM800R: