Natural Gas Conversion Kit Installation Instructions

Safety Considerations and Warnings

Failure to follow this warning may result in damage to unit components.

This kit must not be used on PGD4********2, PGB4********2, PGS4********2, PGB5********2, PGR5********2, WPG4********U and WPG5********U models.

General Safety Considerations

Installation and servicing of this equipment can be hazardous due to mechanical and electrical components. Only trained and qualified personnel should install, repair, or service this equipment.

Untrained personnel can perform basic maintenance functions such as cleaning and replacing air filters. All other operations must be performed by trained service personnel. When working on this equipment, observe precautions in the literature, on tags, and on labels attached to or shipped with the unit and other safety precautions that may apply.

Follow all safety codes. Wear safety glasses, protective clothing, and work gloves. Use quenching cloth for brazing operations. Have fire extinguisher available. Read these instructions thoroughly and follow all warnings or cautions included in literature and attached to the unit.

Consult local building codes, the current editions of the National Electrical Code (NEC) NFPA 70 and NFPA 90B-Installation Warm Air Heating and A/C Systems (Residential). In Canada refer to the current editions of the Canadian Electrical Code CSA C22.1.

Recognize safety information. This is the safety-alert symbol ⚠️. When you see this symbol on the unit and in instructions or manuals, be alert to the potential for personal injury. Understand these signal words: DANGER, WARNING, and CAUTION. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in personal injury or death. CAUTION is used to identify unsafe practices which may result in minor personal injury or product and property damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation.

Failure to follow this warning could result in personal injury, death or property damage.

This conversion kit shall be installed by a qualified service agency in accordance with the manufacturer's instructions and all applicable codes and requirements of the authority having jurisdiction. The qualified service agency is responsible for the proper installation of this kit. The installation is not proper and complete until the operation of the converted furnace is checked as specified in the manufacturer's instructions supplied in the kit.

Failure to follow this warning could result in personal injury, death or property damage.

This conversion kit shall be installed by a qualified service agency in accordance with the manufacturer's instructions and all applicable codes and requirements of the authority having jurisdiction. The qualified service agency is responsible for the proper installation of this kit. The installation is not proper and complete until the operation of the converted furnace is checked as specified in the manufacturer's instructions supplied in the kit.

Failure to follow this caution could result in local or state fines or legal consequences.

Failure to install proper baffles in this unit will violate applicable laws regulating NOx emissions in those districts.

CALIFORNIA INSTALLATIONS ONLY: When this unit is operated with natural gas fuel in certain State of California Air Quality Management Districts, the firing tubes must be equipped with V-shaped NOx baffles to reduce NOx emissions below mandated limits. This unit was originally factory equipped to operate with natural gas fuel and NOx baffles, but the baffles were removed during field conversion to propane gas. These baffles MUST be reinstalled as shown in Fig. 1. If the original baffles are no longer available, order replacement baffles from the factory.

Fig. 1 – Low NOx Baffle Location (California Installations Only): Diagram showing the location of a V-shaped NOx baffle within the firing tube of a furnace, specifically for California installations.

Failure to follow this warning could result in personal injury, death.

This unit is designed to operate at 3.5 IN. W.C. (+/– 0.3 IN. W.C.) of manifold pressure on high stage with natural gas. Refer to Table 4 for proper manifold pressure settings for high stage and low stage.

Two-Stage Kit Contents

* Refer to Table 4 to determine the correct orifice to use.

Two-Stage Kit Installation

Failure to follow this warning could result in personal injury, death or property damage.

Gas supply MUST be shut off before disconnecting electrical power and proceeding with conversion.

Before installing or servicing system, always turn off main power to system. There may be more than one disconnect switch. Lock out and tag disconnect switch with suitable warning label.

1. Turn off gas supply first, then power to unit.
2. Remove the control access panel from unit.
3. Disconnect the gas pipe from the gas valve.
4. Remove the screw attaching the gas manifold to the basepan, and partially slide out the entire burner rack assembly from unit. Save screw. The fan partition mounting bracket may be removed for easier access to the burner assembly. The bracket may be removed by removing 2 screws (located on the left side of the control compartment on the fan partition panel) and sliding the bracket forward, bottom first. See Fig. 5.
5. Disconnect the gray, blue, brown and green/yellow wires from the gas valve and remove violet or blue wires from the rollout switch. NOTE: To locate rollout switch, see Fig. 9.
6. Disconnect orange sparker cable from the sparker.
7. Disconnect white flame sensor wire from the flame sensor.
8. Disconnect low gas pressure switch (see Fig. 11).
9. Remove the ground screw securing the brown wire from the burner assembly. Ground screw is attached to the fan partition. Save screw.
10. Completely slide out the entire burner rack assembly from unit.
11. Using a 5/16 in. nut driver, remove the four screws securing the manifold/gas valve assembly to the burner assembly. Save these screws.
12. For 2-stage 40,000 Btu/hr and 60,000 Btu/hr only (see Fig. 7). Remove the burners from the rack, save the screws. Remove the snap ring from the end of each burner. Remove burner insert in the end of each burner. Replace the snap ring insert (see Fig. 7 for correct orientation). Replace the burners in the rack using the saved screws, making sure closed crossovers of burners are at each end.
13. If there is a low gas pressure switch mounted to the gas valve (see Fig. 10) it must be removed. Disconnect all of the 1/8-in. NPT pipe fittings leading back to the gas valve. Plug the open hole in the gas valve with the 1/8-in. pipe plug contained in this kit. Use a suitable pipe sealant (field-supplied, must be certified for use with natural gas) to prevent leakage of combustible gas.
14. Remove the propane gas orifices from the manifold using a 9/16 in. wrench and install the correct natural gas orifices in the manifold (see Table 4 to select correct orifice size based on rated input. See Fig. 3 and Fig. 6 for orifice installation).
15. Replace the manifold/gas valve assembly into the burner assembly using the four screws saved from Step 11.
16. Remove regulator cover screws for both high and low stage gas regulators (see Fig. 2). Save regulator cover screws.
17. Using a screwdriver, remove plastic adjust screws from both high and low stage gas regulators (see Fig. 2). Save plastic adjust screws.
18. Remove regulator springs (white) from both high and low stage gas regulators (see Fig. 2). Discard regulator springs.
19. Install natural gas regulator springs (silver) shipped with this kit. One into the low stage gas regulator and one into the high stage gas regulator (see Fig. 2).
20. Install plastic adjust screw into the high stage gas regulator, turn clockwise 12 turns (see Fig. 2).
21. Install plastic adjust screw into the low stage gas regulator, turn clockwise 9 turns (see Fig. 2).
22. Verify igniter, flame sensor, orifice/main burner relationship prior to completing conversion. (See Fig. 3.) Partially slide burner rack assembly into unit.
23. Reconnect the violet or blue wires removed in Step 5 to the rollout switch and reinstall the rollout switch.
24. Reconnect the orange wire removed in Step 8, to the combustion air pressure switch.
25. Reconnect orange sparker cable to sparker and reconnect the white flame sensor wire to the flame sensor.
26. Reconnect the remaining wires removed in Step 5 to the gas valve. Connect the gray wires to (HI). Connect the blue wires to (M). Connect the brown and green/yellow wires to (C).
27. Slide burner rack assembly into base pan. Align burner rack with screws on sheet metal partition and slide assembly back tight to the partition. Replace the screw attaching the burner rack to the base pan removed in Step 4. If the Fan partition mounting bracket was removed, slide bracket back into placed and fasten with 2 screws. (See Fig. 5.)
28. Reconnect the brown wire from the burner assembly to the fan partition panel, using the ground screw saved from Step 9.
29. Remove the 1/8 in. pipe plug on the gas manifold and connect a pressure manometer (see Fig. 4).
30. Reconnect electrical power and gas supply to the unit. For natural gas applications, the inlet gas pressure must not be less than 7.0 IN. W.C. or greater than 10.5 IN. W.C. at the unit connection. A 1/8 in. NPT plugged tapping, accessible for test gauge connection, must be installed immediately upstream of the gas supply connection to the gas valve and downstream of the manual equipment shutoff valve.
31. IMPORTANT: Restart unit and leak check all gas connections including the main service connection, gas valve, gas spuds, and manifold pipe plug. All leaks must be repaired before firing unit.
32. Fire unit and verify proper ignition and proper sequence of operation (Table 2). See Table 4 for proper manifold pressure setting for your unit. Adjust the gas valve setting by turning the plastic adjustment screw clockwise to increase pressure and counter-clockwise to decrease pressure. Refer to Table 3 for required rated heating input rates. Replace regulator cover screw when finished (see Fig. 12).

Fig. 2 – Two-Stage Gas Valve: Diagram of a two-stage gas valve, highlighting components like the ON/OFF switch, regulator cover screw, plastic adjust screw, regulator spring, inlet/outlet, pressure taps, manifold, and flame sensor.

Fig. 3 – Two-Stage Igniter, Flame Sensor, Orifice/Main Burner Relationship: Diagram illustrating the relationship between the igniter, flame sensor, orifice, and main burner in a two-stage system.

Fig. 4 – Two-Stage Burner Assembly: Exploded view diagram of a two-stage burner assembly, showing the manifold and pipe plug.

Fig. 5 – Fan Partition Bracket Removal: Diagram illustrating the removal and reinstallation of a fan partition bracket for improved access to the burner assembly.

Fig. 6 – Monoport Burner: Diagram of a monoport burner, showing the burner, manifold, and flame.

Table 2 – Two-Stage Sequence of Operations: Describes the inducer pre-purge, trial-for-ignition, and flame-proving sequences for the furnace.

Table 3 – Two-Stage Rated Heating Input, Natural Gas (0-2000 ft [0-610 m] Altitude): Table listing nameplate input and corresponding rated heating input for natural gas at various stages.

Verify Natural Gas Input Rate

High Stage Input Rate Verification:

1. Turn off all other gas appliances and pilots served by the gas meter.
2. If unit is not running, set unit to run for 20 minutes in high stage gas heat operation using the "INSTALLER CHECKOUT" menu on the UI.
3. Record number of seconds for gas meter to complete 1 revolution.
4. Divide number of seconds in step c, into 3600 (number of seconds in 1 hour).
5. Multiply result of step d. by the number of cubic feet shown for one revolution of test dial to obtain cubic feet of gas flow per hour.
6. Multiply result of step f. by Btu heating value of the gas to obtain total measured input shown in Table 4. (Consult the local gas supplier if the heating value of gas is not known).

EXAMPLE: Assume a 90,000 high stage input unit is being installed. Assume that the size of the dial is 2 cubic ft., one revolution takes 84 seconds, and the heating value of the gas is 1025 Btu/ft³. Proceed as follows: 1. 84 seconds to complete one revolution 2. 3600/84 = 42.9 3. 42.9 x 2 = 85.8 ft³of gas flow/hr. 4. 85.8 x 1050 = 90,090 Btuh input.

In this example, the nominal input rate for high stage is 90,000 Btu/hr, so the high stage manifold pressure is correctly set. If the measured high stage rate is too low, increase the manifold pressure to increase rate. If the measured high stage rate is too high, decrease the manifold pressure to decrease rate.

NOTE: Double-check the User Interface is running on high stage gas heat while clocking the low stage firing rate.

Low Stage Input Rate Verification:

1. Turn off all other gas appliances and pilots served by the gas meter.
2. If unit is not running, set unit to run for 20 minutes in low stage gas heat operation using the "INSTALLER CHECKOUT" menu on the UI.
3. Record number of seconds for gas meter to complete 1 revolution.
4. Divide number of seconds in step c, into 3600 (number of seconds in 1 hour).
5. Multiply result of step d. by the number of cubic feet shown for one revolution of test dial to obtain cubic feet of gas flow per hour.
6. Multiply result of step f. by Btu heating value of the gas to obtain total measured input shown in Table 4. (Consult the local gas supplier if the heating value of gas is not known).

EXAMPLE: Assume a 90,000 high stage input unit is being installed. Assume that the size of the dial is 2 cubic ft., one revolution takes 129 seconds, and the heating value of the gas is 1025 Btu/ft³. Proceed as follows: 1. 129 seconds to complete one revolution 2. 3600/129 = 27.9 3. 27.9 x 2 = 55.8 ft³of gas flow/hr. 4. 55.8 x 1050 = 58,590 Btuh input.

In this example, the nominal input rate for low stage is 58,590 Btu/hr, so the low stage manifold pressure is correctly set. If the measured low stage rate is too low, increase the manifold pressure to increase rate. If the measured low stage rate is too high, decrease the manifold pressure to decrease rate.

NOTE: Double-check the User Interface is running on low stage gas heat while clocking the low stage firing rate.

32. With control access panel removed, observe unit heating operation in both low stage operation and high stage operation. Watch burner flames to verify that they are blue in appearance, and that the flames are approximately the same for each burner (see Fig. 15).

33. Turn off unit, remove pressure manometer and replace the 1/8 in. pipe fitting on the gas manifold (see Fig. 4).

34. Attach warning label (P/N 1177093) to visible side of gas valve.

35. Attach conversion label (P/N 50CY502886) above unit rating plate on exterior of unit.

36. Attach completed conversion responsibility label (see Fig. 8, P/N 50CY502887) inside control access panel.

37. After all leaks are eliminated, replace control access panel.

Fig. 7 - Burner Insert Removal and Orifice Installation: Diagrams showing burner insert removal and orifice installation for 3-cell 60,000 BTUH units and 40,000 BTUH units.

Natural Gas Orifice Sizes and Manifold Pressures

Table 4 - Natural Gas Orifice Sizes and Manifold Pressures

NA = Not Applicable

May be any 2 digits.

Fig. 8 - Conversion Responsibility Label: Image of a conversion responsibility label, with fields for date, kit number, and installer information, including bilingual text (English/French).

Single-Stage Kit Introduction

These instructions cover the installation of a natural gas conversion kit on models PDB4, PDD3, PDD4, PDS3, PDS4, PGB4, PGD3, PGD4, PGD5, PGN4, PGN5, PGS3, PGS4, PGS5, WPG3**4, WPG4**4, and WPG5 that are equipped with a White Rodgers single-stage automatic gas valve regulator.

Failure to follow this warning may result in damage to unit components.

This kit must not be used on PGD4********2, PGB4********2, PGS4********2, PGB5********2, PGR5********2, WPG4********U and WPG5********U models.

Description and Usage

This single-stage kit is applicable to units with heating inputs from 40,000 to 130,000 Btu/hr installed at standard altitudes from 0 ft to 2000 ft. (0-610 m). It cannot be used for high altitude installation. For high altitude conversion please contact your local supplier. All such units were factory equipped to operate on natural gas, but may have been field converted to operate on propane gas. This kit restores the unit to original factory conditions.

Single-Stage Kit Installation

Failure to follow this warning could result in personal injury, death or property damage.

Gas supply MUST be shut off before disconnecting electrical power and proceeding with conversion.

Before installing or servicing system, always turn off main power to system. There may be more than one disconnect switch. Tag disconnect switch with suitable warning label.

1. Turn off gas supply first, then power to unit.
2. Remove the control access panel from unit.
3. Disconnect the gas pipe from the gas valve.
4. Remove the screw attaching the gas manifold to the basepan, and partially slide out the entire burner rack assembly from unit. Save screw. The fan partition mounting bracket may be removed for easier access to the burner assembly. The bracket may be removed by removing 2 screws (located on the left side of the control compartment on the fan partition panel) and sliding the bracket forward, bottom first. See Fig. 5.)
5. Disconnect the gray and brown wires from the gas valve and remove blue wires from the rollout switch. NOTE: To locate rollout switch, see Fig. 9.
6. Disconnect orange sparker cable from the sparker.
7. Disconnect yellow flame sensor wire from the flame sensor.
8. Disconnect low gas pressure switch (see Fig. 11).
9. Remove the ground screw securing the brown wire from the burner assembly. Ground screw is attached to the fan partition. Save screw.
10. Completely slide out the entire burner rack assembly from unit.
11. Using a 5/16 in. nut driver, remove the four screws securing the manifold/gas valve assembly to the burner assembly. Save these screws.
12. For single stage 40,000 Btu/hr and 3 cell 60,000 Btu/hr only (see Fig. 7). Remove the burners from the rack, save the screws. Remove the snap ring from the end of each burner. Remove burner insert in the end of each burner. Replace the snap ring insert (see Fig. 7 for correct orientation). Replace the burners in the rack using the saved screws, making sure closed crossovers of burners are at each end.
13. If there is a low gas pressure switch mounted to the gas valve (see Fig. 17) it must be removed. Disconnect all of the 1/8-in NPT pipe fittings leading back to the gas valve. Plug the open hole in the gas valve with the 1/8-in. pipe plug contained in this kit. Use a suitable pipe sealant (field- supplied, must be certified for use with natural gas) to prevent leakage of combustible gas.
14. Remove the propane gas orifices from the manifold using a 9/16 in. wrench and install the correct natural gas orifices in the manifold (See Table 4 to select correct orifice size based on rated input. See Fig. 13 and Fig. 16 for orifice installation).
15. Replace the manifold/gas valve assembly into the burner assembly using the four screws saved from Step 11.
16. Remove regulator cover screw from the gas regulator (see Fig. 12). Save regulator cover screw.
17. Using a screwdriver, remove the plastic regulator adjust screw from the gas regulator (see Fig. 12). Save plastic regulator adjust screw.
18. Remove regulator spring (white) from the gas regulator (see Fig. 12. Discard regulator spring.
19. Install natural gas regulator spring (silver) shipped with this kit. (See Fig. 12).
20. Install plastic adjust screw into the gas regulator, turn clockwise 12 turns (see Fig. 12).
21. Verify igniter, flame sensor, orifice/main burner relationship prior to completing conversion. (See Fig. 13.) Partially slide burner rack assembly into unit.
22. Reconnect the orange wire removed in Step 8 to the combustion air pressure switch.
23. Reconnect the blue wires removed in Step 5 to the rollout switch and reinstall the rollout switch.
24. Reconnect orange sparker cable to sparker and reconnect the yellow flame sensor wire to the flame sensor.
25. Reconnect the gray and brown wires removed in Step 5 to the gas valve.
26. Slide burner rack assembly into base pan. Align burner rack with screws on sheet metal partition and slide assembly back tight to the partition. Replace the screw attaching the burner rack to the base pan removed in Step 4. If the fan partition mounting bracket was removed, slide bracket back into place and fasten with 2 screws (see Fig. 5).
27. Reconnect the brown wire from the burner assembly to the fan partition panel, using the ground screw saved from Step 9.
28. Remove the 1/8 in. pipe plug on the gas manifold and connect a pressure manometer (see Fig. 14).
29. Reconnect electrical power and gas supply to the unit. For propane applications, the gas pressure must not be less than 7.0 IN. W.C. or greater than 10.5 IN. W.C. at the unit connection. A 1/8-in. NPT plugged tapping, accessible for test gauge connection, must be installed immediately upstream of the gas supply connection to the gas valve and downstream of the manual equipment shutoff valve.
30. WARNING FIRE AND EXPLOSION HAZARD: Failure to follow this warning could result in personal injury and/or property damage. Never test for gas leaks with an open flame. Use a commercially available soap solution made specifically for the detection of leaks to check all connections. A fire or explosion may result causing property damage, personal injury or loss of life.
31. IMPORTANT: Restart unit and leak check all gas connections including the main service connection, gas valve, gas spuds, and manifold pipe plug. All leaks must be repaired before firing unit.
32. Fire unit and verify proper ignition and proper sequence of operation (Table 6). See Table 4 for proper manifold pressure setting for your unit. Adjust the gas valve setting by turning the plastic adjustment screw clockwise to increase pressure and counter-clockwise to decrease pressure. Refer to Table 7 for required rated heating input rates. Replace regulator cover screw when finished (see Fig. 12).

Fig. 12 – Single-Stage Gas Valve: Diagram of a single-stage gas valve, showing components like the ON/OFF switch, regulator cover screw, plastic adjust screw, regulator spring, inlet/outlet, pressure taps, manifold, and flame sensor.

Fig. 13 – Single-Stage Igniter, Flame Sensor, Orifice/Main Burner Relationship: Diagram illustrating the relationship between the igniter, flame sensor, orifice, and main burner in a single-stage system.

Fig. 14 – Single-Stage Burner Assembly: Diagram of a single-stage burner assembly.

Fig. 15 – Monoport Burner: Diagram of a monoport burner, showing the burner flame, burner, and manifold.

Fig. 16 – Single-Stage Orifice Installation: Diagrams illustrating single-stage orifice installation for different BTUH unit ranges.

Fig. 17 – Removing Elbows, Nipples, and Low Gas Pressure Switch on Single-Stage Units: Diagram showing the removal of elbows, nipples, and the low gas pressure switch on single-stage units, detailing connections to the gas valve.

Single-Stage Sequence of Operation

Table 6 - Single-Stage Sequence of Operation

For Units With a Separate Blower Fan Control Board

Trial-for-Ignition Sequence: The ignition sequence is to immediately energize the inducer motor on a call for heat. Within approximately 5 sec of the call for heat, the gas valve will open and the igniter will spark. Seven sec will be allowed to prove flame sense on the far burner.

Flame-Proving: Once flame is proven, the control will wait an additional 45 sec to energize the indoor blower motor. On removal of the call for heat, the gas valve will immediately shut down, the inducer motor will run for an additional 5 sec, and the indoor blower will run for an additional 45 sec (minimum).

For Units With an Integrated Ignition/Blower Fan Control

Trial-for-Ignition Sequence: The ignition sequence is to turn on the inducer motor for 5 second pre-purge after a call for heat is established. The gas valve will then open and the igniter will spark. Seven seconds will be allowed to prove flame to sense on the far burner.

Flame-Proving: Once flame is proven, the control will wait an additional 30 sec to energize the indoor blower motor. On removal of the call for heat, the gas valve will immediately shut down, the inducer motor will run for an additional 5 sec, and the indoor blower will run for an additional 90 sec (minimum).

Single-Stage Rated Heating Input, Natural Gas (0-2000 ft [0-610 m] Altitude)

Table 7 - Single-Stage Rated Heating Input, Natural Gas (0-2000 ft [0-610 m] Altitude)

Final Checks and Labels

Verify natural gas input rate: Follow the detailed steps provided in the document for verifying both high stage and low stage input rates using a gas meter and the provided example calculations.

Final Checks:

• Observe unit heating operation for proper ignition and flame appearance (blue, consistent across burners).
• Turn off unit, remove pressure manometer, and replace the 1/8 in. pipe fitting on the gas manifold.
• Attach warning label (P/N 1177093) to the visible side of the gas valve.
• Attach conversion label (P/N 50CY502886) above the unit rating plate on the exterior of the unit.
• Attach completed conversion responsibility label (see Fig. 8, P/N 50CY502887) inside the control access panel.
• After all leaks are eliminated, replace the control access panel.