AF/AB Series

Agricultural Series Gas-Fired Unit Heaters

Gas-Fired Unit Heaters Certified for Commercial and Industrial Applications

Built to thrive in the harshest environments, our AF/AB Series unit heaters are thoughtfully engineered with durability and performance in mind. Each unit comes standard with a corrosion-resistant cabinet, ensuring long-lasting protection against moisture and airborne contaminants. Inside, high-quality stainless steel components—including tubular heat exchangers, in-shot burners, and flue collectors—deliver superior resistance to rust and corrosion while maintaining optimal heat transfer efficiency. A totally enclosed motor rounds out the robust design, shielding internal components from dust, humidity, and debris. The AF/AB Series isn't just built to perform—it's built to last.

The Sterling AF (propeller) and AB (blower) series convertible venting type tubular gas-fired unit heaters offer a highly efficient, extremely durable alternative to the traditional clam shell design. These propeller and blower type units combine the latest tubular heat exchanger and in-shot burner technology with the quality and reliability you have come to know from Sterling.

Available in 9 sizes from 100,000 to 400,000 BTUs

All AF/AB Series Literature

Standard Features

100 - 400 MBH
83% Thermal Efficiency
Corrosion-Resistant Cabinet
Stainless Steel Tubular Heat Exchangers
Stainless Steel In-Shot Burners
Stainless Steel Flue Collector
Totally Enclosed Motor
Separated or Standard Combustion All-in-One Units
Power Vented
Direct Spark Ignition System
Redundant Single Stage Gas Valve
Rear Burner Access for Ease of Service
Individually Adjustable and Removable Horizontal Louvers
Category I or III Venting
10-Year Heat Exchanger, Flue Collector and Burner Warranty

Corrosion-Resistant Cabinet

Long Lasting Performance

To meet the equipment demands of agricultural facilities, each unit comes standard with a corrosion-resistant cabinet, ensuring long-lasting protection against moisture and airborne contaminants. AF/AB Series unit heater cabinets are built with a state-of-the-art hot-dipped Zinc-Aluminum-Magnesium (ZAM) alloy steel cabinet designed to deliver superior performance and durability in moisture-corrosive environments. The benefits of ZAM Coated Jacketry include;
. Longer life than other coatings
. Cut edge rust protection
. Excellent in severe environments
. Cost saving through less maintenance
. Self-healing properties allow potential scratches to have improved resistance to corrosion

All-In-One Units

Standard or Separated Combustion

The AF/AB Series unit heater is designed to be installed in either standard or separated combustion venting configurations right out of the box, with no modifications required. Optional concentric vent kits are available.

Literature

All the Literature associated with the AF/AB Series

For additional items browse the full Literature library at the link below.

Literature Library

Performance

Performance, Materials and Features for each AF/AB Series capacity model.

Name
MBH Input	100 MBH	400 MBH
Thermal Efficiency	83%	83%

Markets

The AF/AB Series is quite versitile it can be installed in a variety of applications. Here are a few key ways The AF/AB Series can make your space more comfortable.