FDG Indirect Gas-Fired

FDG-Series Indirect Gas-Fired Dehydrators

In the world of industrial drying and dehydrating systems, the choice between indirect gas-fired dehydrators and conventional direct-fired systems is a pivotal decision that can significantly impact process efficiency, product quality, and safety. Indirect gas-fired dehydrators, which employ a heat exchanger to separate the combustion process from the product load, offer numerous advantages over their direct-fired counterparts.

Each system includes a burner assembly, an insulated drying chamber, air handling components, and PLC-based electrical controls with an operator screen to create the perfect conditions to dry your products.

Product Documents

    Benefits of Indirect Gas-Fired Systems

  • Improved Product Quality: Indirect gas-fired dehydrators excel in preserving product quality. In this system, the product load is never exposed to the byproducts of combustion. The heat exchanger, typically a radiant tube, heats the air, which is then gently circulated over the product. This indirect heat transfer method eliminates the risk of contamination and maintains the integrity of the product. In direct-fired systems, the product load comes into contact with recirculated air-containing combustion byproducts, potentially compromising the quality and safety of the final product.

  • Enhanced Safety: Safety is paramount in industrial operations. Indirect gas-fired dehydrators provide a clear advantage by safely venting combustion byproducts to the atmosphere through a chimney system. This design minimizes the risk of harmful gases, such as carbon monoxide, entering the workspace. In direct-fired systems, byproducts are recirculated within the drying chamber, increasing the potential for workplace hazards.

  • Energy Efficiency: Indirect gas-fired dehydrators are more energy-efficient than their direct-fired counterparts. By separating the combustion process from the product load, less energy is wasted. Heat is transferred directly to the air, resulting in faster and more efficient drying, ultimately saving on fuel costs. In direct-fired systems, energy efficiency is compromised as the combustion process and product drying are intertwined, leading to heat loss and higher operating expenses.

  • Greater Flexibility: Indirect gas-fired dehydrators offer increased flexibility in temperature control. The separation of combustion and product load allows for precise control over the drying process. Operators can easily adjust temperatures without the risk of overheating or negatively affecting product quality. In direct-fired systems, adjusting temperatures can be more challenging, as changes in combustion directly impact the product environment.

How Our FDG Indirect Gas-Fired Dehydrators Work

The burner directs the combustible process into a radiant tube, which acts as a heat exchanger. The air passing over the tube is heated before coming into contact with the product load. The byproducts of combustion pass through the tube and are vented to the atmosphere through the chimney system, unlike a direct-fired system, which circulates the byproducts of combustion through the product load.

What Capacity Do You Need?

Which water removal rate best fits your process? Ideal rates are highly product-dependent. However, it can be calculated with three measurements of your existing process: product wet weight, product dry weight, and time from wet to dry.

By finding the product weight change (wet weight minus dry weight) and dividing this by the time measurement (in hours), you can find the average water removal rate (in pounds per hour) occurring in your current process. Next, you can scale this number based on the amount of wet product you wish to start with or the amount of dry product you want to end with. Now, you need to decide how much drying area you need.


Nyle Systems FDG-Series Indirect Gas-Fired series controllers are the best in the industry. Each unit comes with an intuitive touchscreen controller programmed with flexible drying scheduling software. Drying schedules can be saved and modified as necessary and remote access is available as long as there is an internet access point.

Product Comparison


Water Removal Rate

Number of Racks*

Total Drying Space**

Loading Space
(L x W x H )

Total Footprint
(L x W x H )

200+ lbs/hr
18 Racks
1,170 Sq Ft

15' 2" x 5' 7" x 6' 0"

25' 0" x 6' 3" x 11' 0"

300+ lbs/hr
30 Racks
1,950 Sq Ft

24' 10" x 5' 7" x 6' 0"

34' 0" x 6' 3" x 11' 0"

1000+ lbs/hr
138 Racks
8,970 Sq Ft

52' 4" x 11' 0" x 6' 0"

53' 1" x 23' 3" x 10' 4"

* Based on standard rack dimensions of 26" D x 20 3/8" W x 69 1/2" H.
** Based on 20 layers per rack with a capacity of 3.25 Sq Ft per layer.

High Quality 
& Efficient Dehydrators 

High Quality & Efficient Dehydrators 

12 Stevens Rd,
Brewer ME, 04412
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