Reznor UDX400 409-Stainless Steel Power Vented Gas Unit Heater ODP 115V, 1-Stage Gas Valve - Factory Installed

Natural Gas: Natural Gas
Fan Guard: Close Mesh
SF Motor Options: Default

Estimated Arrival: Between and . (To All Contiguous States)

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Reznor HVAC has 130 years of experience manufacturing a wide range of industry-leading industrial and commercial HVAC products. Reznor built its reputation by providing reliable, high-quality heating, ventilation and cooling systems.

Since its founding in 1888, Reznor has remained at the forefront of HVAC technology. Reznor is a global leader thanks to its innovative, extended range of gas-fired unit heaters, air handlers, condensers and rooftop units.



Our industry-leading unit heaters are easy to install and accommodate any need. They feature a compact design that fits into any minimal design. And, their zoning capabilities can save energy by directing the heat where it needs to go. A wide range of energy-efficient, aesthetically-pleasing designs provides many sizes and types to choose from while delivering a durable design with a showroom appearance.



Reznor® model UDX gas-fired unit heaters are great for space heating applications. These units are power vented to eliminate heat losses up the flue pipe. Model UDX is available in 14 sizes ranging from 30,000 to 400,000 BTUH gas input and is approved for installation in the United States and Canada by ETL.

UDX unit heaters feature a two-tone black and white powder-coated, scratch-resistant paint scheme. Each unit has clean rounded corners and edges with no visible screws or fasteners.

For air circulation, model UDX uses an axial propellor fan.

  • Certified for residential heating application
  • Certified for commercial/industrial heating application
  • Up to 82%-83% thermal efficiency
  • 50-60º F temperature rise range
  • 115/1/60 Supply
  • External terminal strip connector for 24-volt wiring
  • Integrated circuit board with 7-segment display
  • External diagnostic LED
  • Hinged access door for easier service
  • Single or two-stage gas valve with external gas service connection
  • 4-point and 2-point suspension
  • Serpentine titanium stabilized heat exchanger design
  • Direct spark ignition with 100% cutoff



Model UDX400
Product Type Unit Heater
Fuel Type Natural Gas or Propane
Gas Control 1-Stage Valve
Ignition Type Direct-Spark
Installation Type Ceiling Mount
Heat Exchanger Material 409 Stainless Steel
Input Heating Capacity 400,000 BTU/H
Output Heating Capacity 332,000 BTU/H
Thermal Efficiency 83%
Gas Connection Size 3/4"
Vent Connection Size
Air Volume CFMs
5123 - M³/minute: 145.1
Motor RPM 1050
Noise Level dBA @ 15ft
Normal Power Consumption
ODP 115V
H 34.125" x W 41" x D 48.90625"


Clearance from Combustibles

Size Top Flue Connector Access Panel* Non-Access Side Bottom* Rear*
30-125 1" 6" 18" 1" 1" 18"
150-400 4" 6" 18" 2" 1" 18"

*Access Panel clearance is required for service clearance to controls
*Bottom Suspend the heater so that the bottom is a minimum of 5’ (1.5M) above the floor.
*Rear clearance is required for air movement. Rear clearance should be measured from the fan motor


The UDX can be used in many markets including:

  • Retail
  • Showrooms
  • Workshops
  • Schools
  • Exhibition Halls
  • Hospital/Medical
  • Sports Facilities
  • Water Treatment
  • Transportation Terminals
  • Industrial Manufacturing
  • Warehouse/Distribution
  • Food & Beverage
  • Residential



Reznor warrants to the original owner-user that this product will be free from defects in material and workmanship. This warranty is limited to twelve (12) months from the date of original installation, whether or not actual use begins on that date, or eighteen (18) months from date of shipment, whichever occurs first.



 Safety Information: See CA Prop 65 Warning