Sterling TF125A1NS111 Heater

The Sterling TF125A1NS111 is a high-efficiency, power-vented industrial gas unit heater designed for rugged commercial environments like warehouses and large workshops. This 125,000 BTU gas heater features a heavy-duty 20-gauge aluminized steel tubular heat exchanger with a serpentine design that eliminates the stress points found in traditional clamshell models, ensuring long-term durability under heavy cycling. Utilizing inshot burner technology and a direct spark ignition system, this natural gas suspended heater achieves an 83% thermal efficiency rating while minimizing standby energy loss.

Operating on a standard 115V single-phase power supply, the unit includes an integrated power venter and a pressure switch to ensure safe combustion and flexible horizontal or vertical venting. The propeller-style fan delivers approximately 2,200 CFM of heated air, controlled by a 24V single-stage gas valve and an advanced LED diagnostic system for simplified troubleshooting on the job site. Contractors will appreciate the individually adjustable louvers for precise air distribution and the factory-installed 120/24V transformer that simplifies field wiring.

• Tubular Heat Exchanger: 20-gauge aluminized steel construction with a non-welded design reduces thermal fatigue and extends service life.
• Enhanced Efficiency: ETL-certified 83% thermal efficiency reduces operational overhead compared to older gravity-vented unit heaters.
• Inshot Burners: Precision-engineered burners isolate the flame within the tube to maximize heat transfer and prevent common corrosion issues.
• Low Maintenance: The built-in diagnostic light allows technicians to identify ignition or pressure issues without opening the cabinet.
• Flexible Installation: Compact low-profile design supports suspended mounting in tight clearances, ideal for commercial retrofits.

What is the proper venting requirement for the Sterling TF125?
This model is a power-vented Category I or III appliance. It requires a dedicated vent pipe; installers should consult the manual for specific horizontal or vertical termination clearances to ensure proper flue gas drafting.

Can this unit be converted to Propane (LP)?
As shipped, the TF125A1NS111 is configured for natural gas. For propane applications, a manufacturer-approved field conversion kit must be installed by a licensed technician to ensure safe manifold pressure and orifice sizing.

Is this heater suitable for use in high-altitude regions?
Standard ratings apply up to 2,000 feet. For installations at higher elevations, the gas input must be derated by 4% for every 1,000 feet above sea level to maintain clean combustion and prevent soot buildup.

This item must ship via truck. Please contact us for freight quote.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.