The conversion kits listed below are intended for use with Williams Furnace Company heaters manufactured after 2013. Conversion kits for furnaces manufactured prior to 2013 may not be currently available. Please call Williams Technical Support at 888-444-1212 to check on availability for your specific furnace.
How to Determine Your Furnace’s Manufacturing Year
To find the year your furnace was manufactured, check the serial number. The serial number is interpreted as follows: digits 1 and 2 indicate the week your furnace was manufactured, and digits 3 and 4 indicate the year.
Conversion Kits and High Altitude Orifices
The following table lists the available conversion kits and high altitude orifices for various Williams Furnace models:
| Furnace Model Number | Furnace Description | Conversion Kits | High Altitude Orifice | High Altitude Kit with All Required Orifices | |||
|---|---|---|---|---|---|---|---|
| Natural Gas to LPG | LPG to Natural Gas | 2001’–4000′ Elevation | 4001’–6000′ Elevation | 6001’–8000′ Elevation | |||
| 1403821 | Direct-Vent Gravity 14,000 Btu/hr. LPG Furnace | N/A | 8942 | P090557 | P090560 | P090561 | 8A144 |
| 1403822 | Direct-Vent Gravity 14,000 Btu/hr. Natural Gas Furnace | 8939 | N/A | P090551 | P090553 | P090553 | 8A141 |
| 2203821 | Direct-Vent Gravity 22,000 Btu/hr. LPG Furnace | N/A | 8943 | P090555 | P090556 | P090556 | 8A145 |
| 2203822 | Direct-Vent Gravity 22,000 Btu/hr. Natural Gas Furnace | 8940 | N/A | P090547 | P090548 | P090550 | 8A142 |
| 2509821 | Monterey Plus 25,000 Btu/hr. LPG Top-Vent Furnace | N/A | 8910 | P090554 | P090554 | P090556 | 9A334 |
| 2509822 | Monterey Plus 25,000 Btu/hr. Natural Gas Top-Vent Furnace | 8907 | N/A | P090544 | P090546 | P090548 | 9A331 |
| 3003821 | Direct-Vent Gravity 30,000 Btu/hr. LPG Furnace | N/A | 8944 | P090553 | P090553 | P090554 | 8A146 |
| 3003822 | Direct-Vent Gravity 30,000 Btu/hr. Natural Gas Furnace | 8941 | N/A | P090541 | P090542 | P090545 | 8A143 |
| 3508231 | Forsaire Top-Vent Counterflow LPG 35,000 Btu/hr. Furnace Intermittent Ignition | N/A | 7717 | P332617 | P090552 | P090553 | 7A312 |
| 3508232 | Forsaire Top-Vent Counterflow Natural Gas 35,000 Btu/hr. Furnace Intermittent Ignition | 7716 | N/A | P090538 | P090540 | P332618 | 7A311 |
| 3508631 | Forsaire Top-Vent Counterflow LPG 35,000 Btu/hr. Furnace Standing Pilot | N/A | 7719 | P090551 | P332619 | P332623 | 7A314 |
| 3508632 | Forsaire Top-Vent Counterflow Natural Gas 35,000 Btu/hr. Furnace Standing Pilot | 7718 | N/A | P090537 | P090540 | P090542 | 7A313 |
| 3509821 | Monterey Plus 35,000 Btu/hr. LPG Top-Vent Furnace | N/A | 8911 | P090552 | P090553 | P090553 | 9A335 |
| 3509822 | Monterey Plus 35,000 Btu/hr. Natural Gas Top-Vent Furnace | 8908 | N/A | P090538 | P090540 | P090543 | 9A332 |
| 4007331 | Forsaire Direct-Vent Counterflow LPG 40,000 Btu/hr. Furnace Intermittent Ignition | N/A | 7729 | P090549 | P090550 | P090551 | 7A324 |
| 4007332 | Forsaire Direct-Vent Counterflow Natural Gas 40,000 Btu/hr. Furnace Intermittent Ignition | 7728 | N/A | P090535 | P090537 | P090539 | 7A323 |
| 4007731 | Forsaire Direct-Vent Counterflow LPG 40,000 Btu/hr. Furnace Standing Pilot | N/A | 7729 | P090549 | P090550 | P090551 | 7A324 |
| 4007732 | Forsaire Direct-Vent Counterflow Natural Gas 40,000 Btu/hr. Furnace Standing Pilot | 7728 | N/A | P090535 | P090537 | P090539 | 7A323 |
| 5008631 | Forsaire Top-Vent Counterflow LPG 50,000 Btu/hr. Furnace Standing Pilot | N/A | 7721 | P332624* | P090554* | P090555* | 7A316 |
| 5008632 | Forsaire Top-Vent Counterflow Natural Gas 50,000 Btu/hr. Furnace Standing Pilot | 7720 | N/A | P090543* | P090544* | P090546* | 7A315 |
| 5009821 | Monterey Plus 50,000 Btu/hr. LPG Top-Vent Furnace | N/A | 8912 | P090554* | P090555* | P090556* | 9A336 |
| 5009822 | Monterey Plus 50,000 Btu/hr. Natural Gas Top-Vent Furnace | 8909 | N/A | P090544* | P090545* | P090547* | 9A333 |
| 5507331 | Forsaire Direct-Vent Counterflow LPG 55,000 Btu/hr. Furnace Intermittent Ignition | N/A | 7731 | P090553* | P332624* | P090554* | 7A326 |
| 5507332 | Forsaire Direct-Vent Counterflow Natural Gas 55,000 Btu/hr. Furnace Intermittent Ign | 7730 | N/A | P090542* | P090543* | P090544* | 7A325 |
| 5508231 | Forsaire Top-Vent Counterflow LPG 55,000 Btu/hr. Furnace Intermittent Ignition | N/A | 7723 | P090553* | P332626* | P090555* | 7A318 |
| 5508232 | Forsaire Top-Vent Counterflow Natural Gas 55,000 Btu/hr. Furnace Intermittent Ignition | 7722 | N/A | P332625* | P090544* | P090546* | 7A317 |
| 6007731 | Forsaire Direct-Vent Counterflow LPG 60,000 Btu/hr. Furnace Standing Pilot | N/A | 7733 | P332627* | P332623* | P332628* | 7A328 |
| 6007732 | Forsaire Direct-Vent Counterflow Natural Gas 60,000 Btu/hr. Furnace Standing Pilot | 7732 | N/A | P090540* | P090542* | P090544* | 7A327 |
| 6008831 | Forsaire Top-Vent Counterflow LPG 60,000 Btu/hr. Furnace Standing Pilot | N/A | 7725 | P090552* | P090553* | P332627* | 7A320 |
| 6008832 | Forsaire Top-Vent Counterflow Natural Gas 60,000 Btu/hr. Furnace Standing Pilot | 7724 | N/A | P090541* | P090542* | P090544* | 7A319 |
| 6508631 | Forsaire Top-Vent Counterflow LPG 65,000 Btu/hr. Furnace Standing Pilot | N/A | 7727 | P332621* | P332627* | P332624* | 7A322 |
| 6508632 | Forsaire Top-Vent Counterflow Natural Gas 65,000 Btu/hr. Furnace Standing Pilot | 7726 | N/A | P090539* | P090541* | P332618* | 7A321 |
| 2001621A | Room Console Heater – Enclosed Front 20,000 Btu/hr. LPG | N/A | 8949 | P501801 | P501803 | P322915 | 9A338 |
| 2001622A | Room Console Heater – Enclosed Front 20,000 Btu/hr. Natural Gas | 8945 | N/A | P501771 | P501802 | P501782 | 9A337 |
| 2509621A | Monterey 25,000 Btu/hr. LPG Top-Vent Furnace | N/A | 8915 | P090554 | P090554 | P090556 | 9A334 |
| 2509622A | Monterey 25,000 Btu/hr. Natural Gas Top-Vent Furnace | 8913 | N/A | P090544 | P090546 | P090548 | 9A331 |
| 3501521A | Room Console Heater – Enclosed Front 35,000 Btu/hr. LPG | N/A | 8950 | P500430 | P500352 | P500431 | 9A345 |
| 3501522A | Room Console Heater – Enclosed Front 35,000 Btu/hr. Natural Gas | 8946 | N/A | P500338 | P500341 | P500342 | 9A344 |
| 3501921A | Room Console Heater – Enclosed Front 35,000 Btu/hr. LPG with Blower | N/A | 8950 | P500430 | P500352 | P500431 | 9A345 |
| 3501922A | Room Console Heater – Enclosed Front 35,000 Btu/hr. Natural Gas with Blower | 8946 | N/A | P500338 | P500341 | P500342 | 9A344 |
| 3502521A | Room Console Heater – Fireplace Front 35,000 Btu/hr. LPG | N/A | 8950 | P500430 | P500352 | P500431 | 9A345 |
| 3502522A | Room Console Heater – Fireplace Front 35,000 Btu/hr. Natural Gas | 8946 | N/A | P500338 | P500341 | P500342 | 9A344 |
| 3502921A | Room Console Heater – Fireplace Front 35,000 Btu/hr. LPG with Blower | N/A | 8950 | P500430 | P500352 | P500431 | 9A345 |
| 3502922A | Room Console Heater – Fireplace Front 35,000 Btu/hr. Natural Gas with Blower | 8946 | N/A | P500338 | P500341 | P500342 | 9A344 |
| 3509621A | Monterey 35,000 Btu/hr. LPG Top-Vent Furnace | N/A | 8916 | P090552 | P090553 | P090553 | 9A335 |
| 3509622A | Monterey 35,000 Btu/hr. Natural Gas Top-Vent Furnace | 8914 | N/A | P090535 | P090540 | P090543 | 9A332 |
| 4505621A | Floor Furnace LPG 45,000 Btu/hr. | N/A | 8955 | P500348 | P500350 | P500351 | 9A377 |
| 4505622A | Floor Furnace Natural Gas 45,000 Btu/hr. | 8953 | N/A | P500332 | P500335 | P500336 | 9A375 |
| 5001521A | Room Console Heater – Enclosed Front 50,000 Btu/hr. LPG | N/A | 8951 | P500346 | P500348 | P500350 | 9A347 |
| 5001522A | Room Console Heater – Enclosed Front 50,000 Btu/hr. Natural Gas | 8947 | N/A | P500331 | P500332 | P500334 | 9A346 |
| 5001921A | Room Console Heater – Enclosed Front 50,000 Btu/hr. LPG with Blower | N/A | 8951 | P500346 | P500348 | P500350 | 9A347 |
| 5001922A | Room Console Heater – Enclosed Front 50,000 Btu/hr. Natural Gas with Blower | 8947 | N/A | P500331 | P500332 | P500334 | 9A346 |
| 5002521A | Room Console Heater – Fireplace Front 50,000 Btu/hr. LPG | N/A | 8951 | P500346 | P500348 | P500350 | 9A347 |
| 5002522A | Room Console Heater – Fireplace Front 50,000 Btu/hr. Natural Gas | 8947 | N/A | P500331 | P500332 | P500334 | 9A346 |
| 5002921A | Room Console Heater – Fireplace Front 50,000 Btu/hr. LPG with Blower | N/A | 8951 | P500346 | P500348 | P500350 | 9A347 |
| 5002922A | Room Console Heater – Fireplace Front 50,000 Btu/hr. Natural Gas with Blower | 8947 | N/A | P500331 | P500332 | P500334 | 9A346 |
| 5009621A | Monterey 50,000 Btu/hr. LPG Top-Vent Furnace | N/A | 8912 | P090554* | P090555* | P090556* | 9A336 |
| 5009622A | Monterey 50,000 Btu/hr. Natural Gas Top-Vent Furnace | 8909 | N/A | P090544* | P090545* | P090547* | 9A333 |
| 6005621A | Floor Furnace LPG 60,000 Btu/hr. | N/A | 8956 | P500344 | P500345 | P500347 | 9A385 |
| 6005622A | Floor Furnace Natural Gas 60,000 Btu/hr. | 8954 | N/A | P500362 | P500364 | P500365 | 9A382 |
| 6501521A | Room Console Heater – Enclosed Front 65,000 Btu/hr. LPG | N/A | 8952 | P500343 | P500344 | P500345 | 9A371 |
| 6501522A | Room Console Heater – Enclosed Front 65,000 Btu/hr. Natural Gas | 8948 | N/A | P500328 | P500329 | P500330 | 9A358 |
| 6501921A | Room Console Heater – Enclosed Front 65,000 Btu/hr. LPG with Blower | N/A | 8952 | P500343 | P500344 | P500345 | 9A371 |
| 6501922A | Room Console Heater – Enclosed Front 65,000 Btu/hr. Natural Gas with Blower | 8948 | N/A | P500328 | P500329 | P500330 | 9A358 |
| 6502521A | Room Console Heater – Fireplace Front 65,000 Btu/hr. LPG | N/A | 8952 | P500343 | P500344 | P500345 | 9A371 |
| 6502522A | Room Console Heater – Fireplace Front 65,000 Btu/hr. Natural Gas | 8948 | N/A | P500328 | P500329 | P500330 | 9A358 |
| 6502921A | Room Console Heater – Fireplace Front 65,000 Btu/hr. LPG with Blower | N/A | 8952 | P500343 | P500344 | P500345 | 9A371 |
| 6502922A | Room Console Heater – Fireplace Front 65,000 Btu/hr. Natural Gas with Blower | 8948 | N/A | P500328 | P500329 | P500330 | 9A358 |
| AC2030TN | High Efficiency Top Vent Gas Wall Heater – NG | M117853 | N/A | NA | NA | NA | NA |
| AC2030TP | High Efficiency Top Vent Gas Wall Heater – LP | N/A | M117854 | NA | NA | NA | NA |
| *Please purchase two high altitude orifices for each furnace model you need to convert. | |||||||