Reznor UDX 125,000 BTU Natural Gas Unit Heater - NUDX125

Reznor UDX 125,000 BTU Natural Gas Unit Heater - NUDX125

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. Each heater features a two-tone black and white powder coated, scratch-resistant paint scheme and has clean rounded corners and edges with no visible screws or fasteners. For air circulation, the UDX series utilize an axial propellor fan.

Features

• 83% AFUE Efficiency
• TCORE2 titanium stabilized aluminized steel heat exchanger
• Multi-try, direct spark ignition with time lockout
• Vibration/noise isolated fan and venter motors designed for low noise operation
• External status indicating LED that blinks if there is a problem that needs service
• 7-segment display board that shows fault code for quick and easy troubleshooting
• Optional integrated downturn nozzle and integrated vertical louvers

What our Experts Think

• Efficient small‑space propane heating
  The Reznor UDX 45,000 BTU Propane Unit Heater (NUDX45, N1036536R) delivers efficient 45 k BTU heating for workshops, garages, utility rooms, or smaller commercial spaces, offering strong warmth without oversizing.
• Solid efficiency for daily use
  With about 83 % AFUE thermal efficiency, it strikes a good balance of fuel economy and heat output, helping manage propane costs over time.
• Durable commercial‑grade build
  Features a TCORE2 titanium‑stabilized aluminized steel heat exchanger for long service life under frequent use, ideal for commercial or workshop environments.
• Quiet, reliable airflow
  The axial propeller fan and power‑vent design promote effective circulation with low noise operation, making it comfortable in busy workspaces.
• Service‑friendly design
  Power‑venting and external gas connection improve installation flexibility, while diagnostic LEDs aid in quick troubleshooting and maintenance.
• Flexible installation options
  Can be ceiling‑mounted or suspended to suit layout needs, and includes options for different venting configurations.

Q&A

Q1: What space size is the Reznor UDX45 heater best for?
A: With 45,000 BTU input and up to ~37,300 BTU output, it’s suited for small to medium garages, workshops, and commercial spaces needing efficient propane heating.

Q2: What fuel type does this model use?
A: It operates on liquid propane (LP) using the factory‑specified propane configuration (SKU N1036536R).

Q3: How efficient is the UDX45?
A: It delivers around ~82–83 % AFUE efficiency, maximizing heat output with reduced energy waste.

Q4: What durability features does this heater include?
A: It features a TCORE2 titanium‑stabilized aluminized steel heat exchanger for long‑term durability and corrosion resistance.

Q5: What are airflow and noise specs?
A: The unit circulates air with an axial propeller fan (~629 CFM) and runs at a low noise level (~40 dBA) — comfortable for workspace environments.

Q6: Is installation and maintenance easy?
A: Yes — the heater includes status LED, 7‑segment diagnostic display, multi‑try direct spark ignition, and external gas connection for straightforward service and troubleshooting.

Q7: What are the electrical and venting requirements?
A: It runs on 115 V single‑phase power (~2.4 A) and uses a 4″ power vent for safe venting of exhaust gases.

Maintenance Tips

• Clean air pathways: Regularly remove dust from the fan, louvers, and intake screen to maintain strong airflow and efficient heat distribution.
• Inspect heat exchanger: Annually check for cracks, corrosion, or soot buildup to ensure safe combustion and long service life.
• Test ignition & propane supply: Verify the direct spark ignition and propane pressure/connections to prevent misfires and uneven heating.
• Keep venting clear: Make sure the power vent and flue are unobstructed to avoid exhaust buildup and heat loss.
• Check electrical components: Inspect wiring, controls, and diagnostic LEDs; tighten loose connections to prevent faults and downtime.
• Verify conversion kit (N1036536R): Ensure proper installation and calibration for safe propane operation.
• Annual professional service: Scheduled servicing helps maintain efficiency, reliable performance, and warranty compliance.