The Sterling XF175A1NS111 is a commercial unit heater rated at 175,000 BTUs with an efficiency rating of 83%. The XF Series uses a Tubular Heat Exchanger - a curved, non-welded design for more uniform heat transfer. The low-pressure drop associated with this design enables heated air to be evenly distributed to the conditioned space. A tubular heat exchanger is an extremely durable alternative to the traditional welded clamshell design. The XF Series is NOT certified for residential use.
The Sterling “XF” Series are all-in-one unit heaters which can be easily converted from standard open combustion (single pipe exhaust) to separated combustion (exhaust and intake pipes) without modification. Located on the rear cover panel of each unit, combustion air inlet collars are left open in a standard combustion venting configuration. When set up for separated combustion, combustion air piping is connected to the inlet collars so that the burners, spark ignitor, and flue system are enclosed within the unit. Air Inlet Kits are available separately and they allow for concentric venting through a single wall or roof opening.
Separated combustion venting configurations are best used where dusty, dirty or mildly corrosive conditions exist, or where high humidity or slightly negative pressures prevail. Standard combustion installation requires vertical or horizontal venting, while separated combustion installations require the Air Inlet Kit for single wall (or roof) penetration. The XF175A1NS111 must be vented outside either horizontally or vertically with 5" venting (a flue collar is supplied). A venting system is required but is not supplied with the unit and must be purchased separately. The “XF” series is ETL certified in accordance with Categories I and III venting requirements. This certification allows units to be vented both vertically and horizontally using either single wall or double wall venting materials. Please refer to the installation manual for separated combustion installation and venting details and requirements. Once installed you and your employees will experience a warmer, quieter thermostat controlled work environment.
These units utilize a direct spark, pilotless ignition of the burner, providing fast heat delivery. This highly reliable and efficient ignition system incorporates an integrated electronic control board to regulate the system sequence of operation, including an externally mounted LED indicator for simple troubleshooting. Designed with the service person in mind, ignition and fan controls can be found in one centrally located control panel.
The unit heater comes standard for Natural Gas usage. An LP gas conversion kit is also available (sold separately). The XF Series has a 115/24V Control Transformer making it usable with 24V thermostats. The 20-gauge steel cabinet of the XF series has a long-lasting baked enamel finish. The tubular heat exchanger, constructed of heavy-duty 20-gauge aluminized steel, carries a 10-year heat exchanger warranty.
For installation, the XF unit heaters have a 4-point suspension for threaded rods. The heater is set for elevations up to 2,000 feet above sea level. For installation above 2,000 ft, the unit must be field adjusted in accordance with the service manual.