Reznor Gas Conversion Kit Installation for Gas-Fired Unit Heaters

General Information

These gas conversion kits are designed for gas-fired unit heaters equipped with either a single-stage or two-stage gas valve. To ensure correct conversion, the complete heater model number, found on the heater rating plate, is necessary. Compare this with the label on the gas valve.

Table 1. Model Configuration

*Standard units may be field-converted to separated-combustion units.

Important Safety Information

Refer to the installation manual provided with the heater for important safety information. Pay attention to all dangers, warnings, cautions, and notes highlighted in this manual. Safety markings are used frequently to designate a degree of seriousness.

A DANGER ⚠️

• All gas conversion must be performed by a qualified service person in accordance with these instructions and all applicable codes and requirements. In Canada, conversions must comply with Provincial Authorities having jurisdiction and CAN/CGA-B149.1 and CAN/CGA-B149.2 installation codes.
• The gas burner is designed for safe, complete combustion. Incomplete combustion, due to inadequate combustion air supply, can produce carbon monoxide, a poisonous gas that can cause death.
• Proper venting of all flue products to the outside atmosphere is crucial for safe operation of indirect-fired gas burning equipment. Failure to provide proper venting creates a health hazard that could cause serious personal injury or death.
• Always comply with combustion air requirements specified in installation codes and instructions. Standard power vent heaters in confined spaces require adequate combustion air as per code and the heater installation manual. For separated-combustion heaters, use the supplied concentric adapter for horizontal or vertical combustion air/vent systems. Combustion air at the burner must be regulated only by manufacturer-provided equipment. Never restrict or alter the combustion air supply. Maintain the vent or vent/combustion air system in a structurally sound and proper operating condition.
• Improper installation, adjustment, alteration, service, or maintenance can cause property damage, injury, or death. Read the installation, operation, and maintenance instructions thoroughly before installing or servicing this equipment.

DO NOT DESTROY. PLEASE READ CAREFULLY. KEEP IN A SAFE PLACE FOR FUTURE REFERENCE.

Heater Component Locations

Figure 1 illustrates the key components of the Reznor unit heater, including the burner assembly, venturi tube, flame sensor, ignitor, circuit board, high temperature limit switch, pressure switch, venter wheel and motor assembly, fan motor, disconnect switch, combination gas valve, and flame rollout switch.

Conversion Kit Selection

A DANGER ⚠️

The conversion kit must be selected and installed by a qualified service person in accordance with these instructions and all applicable codes and requirements. Failure to follow instructions could result in death, serious injury, and/or property damage. The qualified agency performing this work assumes responsibility for the conversion.

Each conversion kit contains specific components, including spring kits and burner orifices. Some parts may not be used; select parts carefully.

Table 2. Conversion Kit Common Components—All Models

Refer to Table 3 for specific burner orifice details.

Table 3. Burner Orifices—All Models

Table 4. NG to LP Kit-Specific Components for UBX, UBXC, UBZ, UDX, UDXC, and UDZ Models

Table 5. LP to NG Kit-Specific Components for UBX, UBZ, UDX, and UDZ Models

Table 6. NG to LP Kit-Specific Components for UDAP, UDAS, UDBP, and UDBS Models

*The plate from kit PN 1036538R is not used on unit size 125 models. The plate from kit PN 1036539R is not used on unit size 175 models for residential or commercial applications.

Installation

Install the conversion kit following these steps, ensuring the kit is correct for the heater size.

1. Remove gas supply and electrical power:
   • Turn OFF gas supply at the shutoff valve outside the heater.
   • Turn OFF electrical power.
   • Open the control access panel.
2. Install regulator spring kit:

   A WARNING ⚠️ Regulator spring kits are not interchangeable. Use only the kit designated for the specific gas valve model and type. Verify compatibility before installation.

   • Select the regulator spring kit that matches the gas valve on the heater. Conversion kits include one or two spring kits for single-stage valves and one for two-stage valves; unused kits should be discarded.
   • Install the regulator spring kit according to the gas valve manufacturer's instructions, which are included with the kit.

A CAUTION ⚠️ After installing a new regulator spring kit, adjust the spring to set manifold pressure. This adjustment is made while the heater is operating (refer to step 7).

3. Remove or install air restrictor plate as necessary and replace burner orifice:
   • Carefully remove the existing burner orifice (see Figure 2, DETAIL A).

   A DANGER ⚠️

   • The air restrictor plate MUST BE INSTALLED when converting unit sizes 30, 45, 60, 75, 100, and 150 (all models) and unit size 125 (models UDBP, UDBS, UBX, UBXC, and UBZ) to propane.
   • The air restrictor plate MUST BE REMOVED when converting unit sizes 30, 45, 60, 75, 100, and 150 (all models) and unit size 125 (models UDBP, UDBS, UBX, UBXC, and UBZ) to natural gas.
   • Failure to install or remove the air restrictor plate as directed for these models/unit sizes can cause death, injury, and/or property damage.
   • For unit sizes 30, 45, 60, 75, 100, and 150 (all models) and unit size 125 (models UDBP, UDBS, UBX, UBXC, and UBZ), proceed to step c. For all other models/unit sizes, proceed to step e.
   • If converting from propane to natural gas, remove the air restrictor plate. If converting from natural gas to propane, install the air restrictor plate per step d.
   • See Figure 2, DETAIL B for locating the air restrictor plate held by bent tabs on the venturi tube.
   • Use pliers to unbend tabs (as shown in Figure 2, DETAIL A) to remove the air restrictor plate.
   • For natural gas to propane conversion, refer to Table 4 or Table 6 to select the correct air restrictor plate. Slide the plate over the venturi tube opening, hooking the 45-degree angle over the rear of the venturi tube (see Figure 2).
   • While holding the plate, use pliers to bend the tabs to secure the plate (see Figure 2, DETAIL B). Ensure the air restrictor is aligned and secure.

   Figure 2 shows the Burner Orifice and Air Restrictor Plate. DETAIL A illustrates the plate with tabs not bent, and DETAIL B shows the plate installed with tabs bent. The asterisk indicates the plate is used only on specific unit sizes and models for propane conversion.

   • For all conversions, select replacement burner orifices according to Table 3. Conversion kits include two or three orifices; other included orifices will not be used.

   A WARNING ⚠️ Do not attempt to drill burner orifices. Use only factory-supplied orifices.

   • Install the replacement burner orifice (see Figure 2, DETAIL A).
4. High-Elevation Operation:

   A CAUTION ⚠️ If the heater will operate at elevations above 6,000 feet (>1,830 meters), a high-elevation pressure switch must be installed.

   • NOTES:
   • If the installation elevation is >6,000 feet (>1,830 meters), verify the rating plate or high-elevation label indicates this elevation. If not, order and install the appropriate high-pressure switch kit.
   • If the heater is equipped for high-elevation installation but is being installed at a lower elevation, order and install the appropriate switch.
   • Contact your distributor for factory-authorized replacement parts (refer to the replacement parts manual).
5. Replace pressure switch (for installations >6,000 feet): Follow instructions in the Pressure Switch Replacement section of the installation/operation/maintenance manual.
6. Restore electrical power and gas supply:
   • Turn ON electrical power.
   • Turn ON gas supply and relight the heater following the heater's instructions.
7. Perform leak test:
   • Check all connections for gas leaks using commercial leak-detecting fluid or a soap and water solution. Bubbles indicate leaks.
   • If a leak is detected and cannot be stopped by tightening the connection, replace the affected part(s).

   NOTES:

   • Conversion kits do not alter the heater's input rate. Refer to the rating plate for input rate and other information.
   • Adjusting for high-elevation operation will affect the input rate.
   • The high-elevation adjustment label is not used for units operating at elevations of ≤2,000 feet (≤610 meters).
8. Adjust manifold (outlet) gas pressure: Follow instructions in the Measure and Adjust Manifold (Outlet) Gas Pressure section of the installation/operation/maintenance manual.
9. Close control access panel.