Sterling XF Series Gas-Fired Unit Heaters

High-Efficiency Heat for Commercial and Light-Commercial Spaces

The Sterling XF Series Gas-Fired XF400A1NS111 Unit Heater delivers powerful, efficient heating performance for warehouses, workshops, commercial garages, and other light-commercial environments. Built with a tubular heat exchanger and in-shot burner system, this rugged heater is engineered for superior durability and long service life. Its curved, non-welded serpentine design reduces thermally induced stress and creates a low-pressure drop ensuring even air distribution and dependable comfort throughout your space—all in a compact, propeller-style unit heater.

Engineered for Efficiency & Reliability

The XF Series’ tubular heat exchanger maximizes surface area for exceptional heat transfer while minimizing thermal stress. Constructed from heavy-duty 20-gauge aluminized steel, these heaters are built to last. This 400 MBH (400,000 BTU) unit, provides effective comfort for both commercial and light-industrial heating applications. This model delivers 83% thermal efficiency, verified by ETL certification.

Flexible Venting Options

Every Sterling XF Series Unit Heater is designed for standard or separated combustion, giving installers maximum flexibility without extra conversion kits. For standard venting, the combustion air inlet remains open to the surrounding atmosphere. For separated combustion, air intake piping connects directly to the rear inlet collar, isolating the burner and flue system from the room environment. This design is ideal for dusty, dirty, or high-humidity conditions where clean combustion air is essential for performance and safety.

The XF Series also meets Category I and III venting standards, allowing both vertical and horizontal venting using single-wall or double-wall materials. Optional concentric vent kits simplify installation by combining intake and exhaust through a single termination point—ideal for clean, professional installations.

Smart Ignition & Service Accessibility

Sterling XF heaters feature a direct spark ignition system that eliminates the need for a standing pilot light. The integrated electronic control board manages all ignition and fan functions, with a visible LED status indicator for quick diagnostics. All controls are centrally located for easy service access—designed with HVAC professionals in mind.

QUICK FACTS

400 MBH (400,000 BTU) heating capacity

Gas-fired tubular heat exchanger design for long-term durability

83% combustion efficiency (ETL certified)

Propeller-style fan for open-space air circulation

Convertible for standard or separated combustion (no modifications required)

Vertical or horizontal venting with concentric kit options

Direct spark ignition with LED status indicator

Heavy-duty aluminized heat exchanger

Easy-access service panel and centralized control system

Warranty

The XF400A1NS111 comes with a standard 10 year heat exchanger warranty from the manufacturer.

Additional Information

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