1. Introduction
This manual provides essential instructions for the safe and efficient installation, operation, and maintenance of your Reznor UDXC-125 Natural Gas Unit Heater. Please read this manual thoroughly before attempting any installation or operation. Retain this manual for future reference.
The Reznor UDXC-125 is a 120,000 BTU natural gas-fired, forced-air unit heater designed for indoor use in various commercial, industrial, and residential spaces such as garages, workshops, and warehouses. It features an 83% thermal efficiency rating and is built with durable components for reliable performance.
Figure 1: Front view of the Reznor UDXC-125 Natural Gas Unit Heater. This image displays the compact design of the heater with its front grille and the Reznor branding on the side.
2. Safety Information
WARNING: Improper installation, adjustment, alteration, service, or maintenance can cause property damage, injury, or death. Read the installation, operating, and maintenance instructions thoroughly before installing or servicing this equipment.
This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.
- Always ensure proper ventilation when operating the heater.
- Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.
- Keep the area around the heater clear of combustible materials.
- Installation and service must be performed by a qualified installer, service agency, or gas supplier.
- Ensure all gas and electrical connections comply with local codes and regulations.
3. Setup and Installation
The Reznor UDXC-125 heater is designed for indoor use and can be mounted from the ceiling or on a wall. Mounting hardware is sold separately. Ensure the chosen location provides adequate clearance from combustible materials and allows for proper venting.
3.1 Mounting Options
The unit features threaded-nut retainers at four suspension points, facilitating secure ceiling or wall mounting. Consult local building codes for specific mounting requirements.
Figure 2: Reznor UDXC-125 Unit Heater suspended from a ceiling. This image illustrates the heater's capability for ceiling installation, highlighting its compact form factor in an industrial setting.
3.2 Venting Requirements
This unit is compatible with Category 3 single-wall vent pipe. Venting can be configured vertically through a roof or horizontally through a sidewall. Proper venting is crucial for safety and efficient operation, ensuring exhaust gases are safely expelled.
3.3 Gas and Electrical Connections
- An external gas connection point is provided for ease of maintenance and installation.
- The unit requires a 24V electrical connection, accessible via an external terminal strip.
- A built-in enhanced disconnect switch is included for safety during service.
- All connections must be made by a licensed professional in accordance with all applicable local and national codes.
4. Operating Instructions
The Reznor UDXC-125 features an integrated circuit board with a 7-segment display and status-indicating LED for operational feedback.
4.1 Starting the Heater
- Ensure the gas supply valve is open.
- Verify electrical power is supplied to the unit and the disconnect switch is in the "ON" position.
- Set the thermostat to the desired temperature. The heater will initiate its ignition sequence.
- The status-indicating LED and 7-segment display will provide feedback during startup and operation.
4.2 Heating Flexibility
The single-burner design offers two BTU outputs, allowing for efficient heating in varying conditions. A higher output is available for colder days, and a lower output for milder temperatures, optimizing energy use.
Figure 3: Reznor UDXC-125 Unit Heater installed in a workshop. This image demonstrates the heater's application in a typical workspace, illustrating its heating flexibility for different environmental needs.
4.3 Air Circulation
The unit utilizes a low static pressure axial fan and power venting to ensure effective air circulation and minimize heat loss, distributing warmth evenly throughout the space.
5. Maintenance
Regular maintenance ensures the longevity and efficient operation of your Reznor UDXC-125 heater. Always disconnect power and gas supply before performing any maintenance.
- Annual Inspection: Have a qualified service technician inspect the heat exchanger, burner, ignition system, and venting system annually.
- Cleaning: Keep the area around the heater clean and free of dust and debris. Periodically clean the fan blades and motor to ensure optimal airflow. The updated cabinet structure with a removable front face and hinged access door panel simplifies access for cleaning and service.
- Filter Replacement: If your installation includes an air filter, inspect and replace it regularly according to manufacturer recommendations.
6. Troubleshooting
The integrated circuit board with a 7-segment display and status-indicating LED provides diagnostic codes to assist in troubleshooting. Refer to the specific diagnostic code chart in the full installation manual for detailed information.
| Problem | Possible Cause | Solution |
|---|---|---|
| Heater does not turn on. | No power, gas supply off, thermostat setting too low, safety lockout. | Check power supply and disconnect switch. Ensure gas valve is open. Adjust thermostat. Check LED for lockout codes. |
| Heater cycles on and off frequently. | Improper thermostat placement, restricted airflow, oversized unit. | Relocate thermostat away from drafts or heat sources. Clear obstructions from air intake/output. Consult a professional. |
| Insufficient heating. | Low gas pressure, dirty burner, fan issues. | Verify gas pressure. Clean burner. Inspect fan for proper operation. Contact service technician. |
For complex issues or if diagnostic codes persist, contact a qualified HVAC service technician.
7. Specifications
| Feature | Detail |
|---|---|
| Model | UDXC-125 |
| Heat Output | 120,000 BTU |
| Fuel Type | Natural Gas |
| Thermal Efficiency | 83% AFUE |
| Indoor/Outdoor Usage | Indoor Only |
| Mounting Type | Ceiling Mount, Wall Mount (mounting hardware sold separately) |
| Product Dimensions (D x W x H) | 34.28" x 27" x 24.75" |
| Fan Type | Low Static Propeller Fan |
| Heat Exchanger | TCORE2 Titanium-Stabilized Aluminized Steel |
| Special Features | Fast Heating, Integrated Circuit Board with 7-Segment Display, Status-Indicating LED, Built-in Disconnect, Multi-Try Direct Spark Ignition, External Gas Connection, ETL Approved |
Figure 4: Dimensions of the Reznor UDXC-125 Unit Heater. This image provides a visual representation of the heater's physical size, indicating its depth, width, and height.
8. Warranty and Support
For warranty information, please refer to the documentation provided with your purchase or contact the seller, 1HVAC, directly. Keep your proof of purchase for warranty claims.
For technical support or service inquiries, please contact your authorized Reznor dealer or the point of purchase. Ensure you have your model number (UDXC-125) and serial number ready when contacting support.
