Skip to product information
1 of 1

SKU:3508231

Williams Furnace 35,000 BTU Forsaire Top - Vent Counterflow Intermitted Ignition Furnace

Williams Furnace 35,000 BTU Forsaire Top - Vent Counterflow Intermitted Ignition Furnace

Regular price $3,999.99
Regular price Sale price $3,999.99
Sale Sold out
Fuel Type

Thermostat & Venting Options

Gas Conversion Kit

  • Free Shipping on Orders Over $300
  • Same-Day Order Processing
  • Easy Monthly Installments Starting at 0% APR*
Got a question?
• Text or call 888-992-1556
• Email support@usfireplacestore.com
• Start a live chat

Our team is available to serve you 8:00 AM - 11:59 PM ET, 7 days a week.

Overview

Williams Comfort Products Made In America Since 1916!

For over 100 years, Williams has designed and manufactured quality heating, ventilation, and air conditioning products for both the home and business. It all started in 1916, when Jesse Williams began building gas steam radiators in Los Angeles under the banner Williams Radiator Company. Williams’ commitment to quality was clear from the start, and the company’s product line expanded over the next few decades to include gas-fired heating, gravity wall heating and counterflow furnaces. By 1954, Williams had expanded to a nationwide player, with a distribution and sales network that reached customers throughout the United States.

Williams reputation for quality products only increased, and in 1958 they were acquired by Continental Materials Corporation, an AMEX-listed company whose notoriety brought new levels of prestige to the firm, now called Williams Furnace Company. The company acquired Hydro-Aire/LANCO in 1986, a major manufacturer of fan coils and air handlers. As a result, Williams now offers more fan coil sizes and configurations than any other HVAC company in all of the United States. Finally, the product line was expanded in 1996 to include room console heaters.

Jesse Williams understood that his company had to adapt to grow, and so do we. Today, numerically controlled machinery is used to ensure both precision and quality. All Williams products are tested to the highest standards according to specifications set by the National Bureau of Standards. Engineering, R&D, testing and manufacturing take place at our factory in Colton, California.

Above all, we aim to treat the customer with respect and integrity to ensure that our customers come to expect the same quality from us that they will from our fine line of products.

Heating Solution to Fit Any Project Need

For nearly 100 years, Williams has offered a wide range of safety-tested, cost-efficient heating solutions to fit any home. From a studio apartment to a palatial estate, we’ve got you covered with a complete line of heating products, including both gas and electric furnaces. Come inside, and let Williams warm you up.

Forsaire Counterflow Furnaces

Top - Vent Counterflow

Models require less than one square foot of floor space. They may be recessed int the stud space or surface mounted and vented vertically through the ceiling and roof.

 Features and Benefits

  • Freestanding or recessed, Forsaire™ furnaces are ideal for homes, apartments, offices, schools, cabins and many other applications
  • Counterflow blower system circulates ceiling-to-floor warm air
  • “Matchless” pilot igniter
  • Multi-room heating with optional outlet accessories to heat up to three rooms
  • Equipped with a four-foot service cord
  • Natural or propane models (conversion kits available)
  • Automatic temperature and safety controls
  • Resettable vent-limit safety switch (top-vent models)
  • Thermostat Sold Separately - Part #8967

Dimensions and Clearances

  • 4" to an intersecting wall
  • 4" from the top of the furnace to the ceiling or overhang
  • 2" from the top of the furnace to the ceiling or overhang on 60085 Series
  • 0" to finished floor


 Accessories      

Click to See Additional Accessories 
Williams Furnace Ignition Control Wires for 3508/5008/5508 Series

This replacement ignition shield is for use with specified Williams Forsaire Counterflow Direct Vent and Top Vent Furnaces.

  
It is compatible with the following Counterflow Direct Vent models:
  • 4007332, 4007331
  • 5507332, 5507331
It is compatible with the following Counterflow Top Vent models:
  • 3508231, 3508232
  • 5508231, 5508232
Williams Furnace 4318 Vent Shield Deflector for all Direct Vent Models ( Except HE DV )

This vent shield deflector is an insulated, galvanized metal sheet made for use with Direct Vent Furnaces.


To be used on the following direct vent models:

  • Natural Gas Models:
    • 14,000 BTUs: 1403822, 1413822,1433822, 1453822
    • 22,000 BTUs: 2203822, 2313822, 2233822, 2253822
    • 30,000 BTUs: 3003822, 3013822, 3033822, 3053822
  • Liquid Propane Models:
    • 14000 BTUs: 1403821, 1413821,1433821, 1453821
    • 22,000 BTUs: 2203821, 2313821, 2233821, 2253821
    • 30,000 BTUs: 3003821, 3013821, 3033821, 3053821

Williams Furnace Trim Strip Accessory

Give your furnace a finished look. This metal molding strip is painted to match and is for use with the following Forsaire furnaces. The trim kit includes 4 trim strips. You will be using 2 per side of your furnace butted together in the center of each side of the furnace. There are no trim strips for the top or bottom of your furnace. This trim set finishes the sides only.

Monterey Plus Top Vent Furnaces:
  • 25098 Series: 2509821, 2509822
  • 35098 Series: 3509821, 3509822
  • 50098 Series: 5009821, 5009822
Williams Furnace Rear Outlet Register with 10” Boot and Damper for Forsaire Electric

Add this rear-register to your Forsaire Electric heater to add heat to a second rear connected room.

  • Rear-Outlet Register
  • 10" Boot
  • Damper

Williams Furnace Two-Way Diffusing Grille for all Forsaire Models

A diffusing grille snaps on to the front of your Forsaire system. With this two-way diffusing grille, you can direct the heated air from the front of your furnace to the right and left for a more dispersed airflow.

Williams Furnace One-Way Diffusing Grille for all Forsaire Models

With this one-way diffusing grille, your heated air comes into the room and you have to option of one way air flow/direction.

 
For use with the following Forsaire furnaces.

Counterflow Top Vent Furnaces:
  • 3508 Series: 3508231, 3508232, 3508631 3508632
  • 500, 550 and 650 Series: 5008631, 5008632, 5508231, 5508232, 6508631 6508632,

Williams Furnace Rear Outlet Register with 10” Boot and Damper for Top-Vent Furnaces

With the addition of a rear outlet register, you can add heat to a rear adjacent room. The finished wall of the second room must be within 10 inches of the furnace. Everything you need, the rear outlet register, a 10" boot and a damper, is included to heat the second area. The built-in damper lets you shut off the air flow to the second room if desired.

Williams Furnace 9902 Vent Adapter (Freestanding Installations) without a Blower Installed

This vent adapter is to be used only in a surface mounted/freestanding installation of a Monterey and Forsaire Single Sided Heater. To be used when there is no blower installed.


This vent adapter is for use when typical venting installation cannot be followed - for example when the furnace is being vented into a chimney.
 
Measurements for this vent adapter are:
  • 8-1/2" top to bottom
  • 7" deep at the top
  • 3-1/2" deep at the bottom
Includes Vent Adapter, Fiberglass Gasket and 4 #10 screws
Oval Vent Starter Kit (includes hold-down plate) US

Convert from an oval to round vent with this easy-to-use conversion kit.

Includes:
  • Hold Down Plate (1)
  • Starter Plates (2)
  • 4" Oval Pipe 2' length (2)
  • 4" Oval to Round Adapter (1)
For use with Forsaire 3508, 5008, 5508, and 6508 Top Vent Furnaces.

Oval Vent Starter Kit (includes hold-down plate) Canada

Convert from an oval to round vent with this easy-to-use conversion kit.

Includes:
  • Hold Down Plate (1)
  • Starter Plates (2)
  • 4" Oval Pipe 2' length (2)
  • 4" Oval to Round Adapter (1)
For use with Forsaire 3508, 5008, 5508, and 6508 Top Vent Furnaces.

Williams Furnace Hard-Wire Converter for all Forsaire Models

Hard Wire Converter is used to convert the standard electric plug on a Williams Forsaire Counterflow furnace to a hardwire installation using a junction box. It can be used on all Forsaire Counterflow furnaces from 35,000 BTUs up to 60,000 BTUs.

Williams Furnace 8967 Millivolt Wall Thermostat Kit for all Williams Heaters (Includes Wire and Nut)

Williams Furnace Company no longer includes thermostats with their furnaces. This wall thermostat can be used with all Williams Furnaces. Simply move the switch to your desired temperature setting. It is easy to operate with its slide control and can be set from 50°F to 90°F. This thermostat kit includes the thermostat and 14 feet of wire. 

Williams Furnace P322016 Millivolt Wall Thermostat Only for all Williams Heaters

The standard millivolt Williams Furnace thermostat. It is easily replaceable and will work with all Williams heaters. It can be wall or unit mounted. It is easy to operate with its slide control and can be set from 50°F to 90°F.

Williams Furnace P332491 Wireless Digital Wall Thermostat for all Williams Heaters

 

This wall thermostat has an easy to read LCD screen and is battery operated.

  • For Monterey, Direct Vent Gravity and Console Hearth Heaters
  • Wall mounted installation
  • Thermostat or Manual on/set/off
  • Easy to read LCD screen
  • Displays room temperature in Fº or Cº
  • Operation Range: 45 to 99 Fº
  • Battery operated

This product is manufactured by Skytech.

Williams Furnace P332492 Wireless Remote Control for all Williams Heaters

 

Turn your heater on or off, or change the temperature, all with the touch of this 4 button remote control.

  • Three Functions: On - Off - Thermostat setting
  • Displays room temperature in ºF or ºC
  • Battery operated
  • Four button control
  • Velvet-touch casing
  • Receiver included

Williams Furnace P332493 Digital Wall Thermostat for all Williams Heaters

This wall thermostat has an easy to read LCD screen and is battery operated.

  • For Monterey, Direct Vent Gravity and Console Hearth Heaters
  • Wall mounted installation
  • Thermostat or Manual on/set/off
  • Easy to read LCD screen
  • Displays room temperature in Fº or Cº
  • Operation Range: 45 to 99 Fº
  • Battery operated

This product is manufactured by Skytech.

Click to See Gas Conversion Kit

Williams Furnace 7716 Gas Conversion Kit - Natural Gas to Propane Gas for 3508232

Use this gas conversion kit to convert your Forsaire Furnace Natural Gas heater to Liquid Propane Gas. Parts shown in picture may differ according to specific model.

  • For 35,000 BTU Forsaire Furnaces, 35082 Series

Williams Furnace 7717 Gas Conversion Kit - Propane Gas to Natural Gas for 3508231

Use this gas conversion kit to convert your 35000 BTU Forsaire Furnace Liquid Propane heater to Natural Gas. Parts shown in picture may differ according to specific model.

  • For 35,000 BTU Forsaire Furnaces, 35082 Series

 

Click to See High Altitude Conversion Kit
Williams Furnaces High Altitude Conversion Kit with all Required Orifices for 3508231
This high elevation kit is specifically for use with your Williams Propane Gas 35,000 BTU Forsaire Top Vent Counterflow Furnace with Intermittent Ignition. It includes all required orifices to meet your specific elevation needs. A high elevation kit is required for elevations over 2,000 feet above sea level.
 
Orifices are included for the following elevations:
  • 2001' to 4000' above sea level - P332617
  • 4001' to 6000' above sea level - P090552
  • 6001' to 8000' above sea level - P090553x`

Williams Furnace High Altitude Conversion Kit with all Required Orifices for 3508632

This high elevation kit is specifically for use with your Williams Natural Gas 35,000 BTU Forsaire Top Vent Counterflow Furnace with Standing Pilot. It includes all required orifices to meet your specific elevation needs. A high elevation kit is required for elevations over 2,000 feet above sea level.
 
Orifices are included for the following elevations:
  • 2001' to 4000' above sea level - P090537
  • 4001' to 6000' above sea level - P090540 
  • 6001' to 8000' above sea level - P090542

Click to See Vent Accessories

Williams Furnace 12" Vent Tubes for Direct-Vent Furnaces

Twelve inch direct vent tube extension replaces tubes which come with furnace. For use when venting your Williams direct vent furnace outdoors. Models include all Forsaire 40,000, 55,000, 60,000 BTU Direct Vent Furnaces, whether it has a standing pilot or intermittent pilot.

Williams Furnace Thin-Wall Collar Kit for all Direct Vent Models (Except HE DV)

The Williams thin wall collar kit is for use when installing a direct vent furnace on walls with thicknesses from 1" to 5". It installs with a vent kit with Williams Direct-Vent models including 1403621,1403622, 2203621, 2203622, 3003621 and 3003622.

 
It can also be used to extend the vent cap away from the outside wall when mounting the vent cap onto vinyl siding or greenhouse coverings. This prevents damage for the exhaust on these materials.
 
The four pieces fit together forming a square/rectangle.

Williams Furnace Direct Vent Cap Guard for All Direct Vent Models (Except HE DV)

if your direct vent furnace is venting to a heavily traveled or pedestrian area you can protect them from the hot air emitted from your furnace. This vent cap guard keeps vented hot air from outdoor pedestrian traffic. For all Williams Direct Vent furnaces.

Williams Furnace 12" Vent Enclosure for Forsaire Top-Vent

This metal vent enclosure can be used on the side or in front and is painted the same color as the furnace and is used to enclose the vent pipes of all Top Vent furnaces. Forsaire models include 3508, 5008, 5508 and 6508.

 
Available in 12", 24" or 36" length.

This item is 12" long.
 
Requires (2) two for side use.

Williams Furnace 24" Vent Enclosure for Forsaire Top-Vent

This metal vent enclosure can be used on the side or in front and is painted the same color as the furnace and is used to enclose the vent pipes of all Top Vent furnaces. Forsaire models include 3508, 5008, 5508 and 6508.

 
Available in 12", 24" or 36" length.

This item is 24" long.
 
Requires (2) two for side use.

Williams Furnace 36" Vent Enclosure for Forsaire Top-Vent

This metal vent enclosure can be used on the side or in front and is painted the same color as the furnace and is used to enclose the vent pipes of all Top Vent furnaces. Forsaire models include 3508, 5008, 5508 and 6508.

 
Available in 12", 24" or 36" length.

This item is 36" long.
 
Requires (2) two for side use.

Important

  • Any warranty considerations are contingent on installation by a qualified installer (contractor). Self-installation is prohibited and will invalidate your warranty.
  • Read owner’s manual before using/installing.
  • Photographs are representative.
  • Check local codes and ordinances for permitted uses.
  • Consult installation manual for clearances prior to installation.
  • We reserve the right to amend product specifications without notice.
  • Installation and servicing recommended by a qualified service person.
  • Venting must comply with the installation manual.
  • Massachusetts Approval G3-0115-271.
  • Please read the warranty for any limitations or disclaimers.
  • Combustion chamber carries a ten-year limited warranty. All other parts carry a one-year limited warranty.

Videos

Williams Furnace Locating and Replacing Orifice

 Williams Furnace Advanced Gas Heating Training

Downloads

Safety Information : CA Prop 65 Warning


View full details
  • Researched and ordered my fireplace from US FIreplace Store. Pricing was a fair value however, the customer service was EXCELLENT! I had an issue with the direct vent venting. I called US Fireplace and the correct items were sent out the next day AND Janessa stayed on top of my return authorization and sent me the permissions and documents I needed to return the incorrect item and no cost to me, including return shipping. Overall, I am a very satisfied customer and my fireplace looks and operates flawlessly. I am glad that I selected US FIreplace to source my direct vent fireplace. Thank you for the great service.

    Clay

    Monteagle, TN

  • I had placed an order, through Lowe's Home Improvement, for an Electric Firebox: Revillusion RBF42. Ordered 1st part of January. Was told I would have it in 3 weeks. When checking to see is it came in, was told it was delayed to 3/15. Was then told is was delayed until 4/25. Waited until 4/27 to check on it. Was then told it was now delayed until August. This firebox was going in a new Sun Room addition. I could not get my final inspection until the Firebox was installed. I went on line and googled for this same product. US Fireplace Store web site was given to me. This was on a Saturday. I call and reached a very nice man. Explain what I was look for. He checked and told me they had 30 of them in stock. I almost fell out of my chair. I clarified with him the product I was wanting. I ask how soon could I get it. He told me it would ship today. Again, was amazed. It arrived on the following Monday. What a pleasure and a relief working with US Fireplace Store and their employees. Exceed my expectations.

    Thomas W.

    Fort Mill, SC

  • Great prices, quick delivery and fast hassle free services on the issue I encountered. I had purchased an electric fireplace unit that would not fit into the existing fireplace space. With one email I was able to get the wrong fireplace refunded and picked up at my home at no extra cost and the new one I purchased and delivered free of charge. Great company.

    John P.

    Denvers, MA

1 of 12
  • Live Chat Support

    No chatbots. Speak with a human. Average response time is 48 seconds.

  • Easy Returns

    Need to return the merchandise? We accept returns for 30 days from the date of delivery.

  • 7 Days/Week Service

    We're here to help on live chat, email & phone. 8:00 AM - 11:59 PM Eastern Time.

  • 20,000+ Products

    Best selection of hearth & heating products on the internet. Fireplaces, stoves, fire pits, heaters, log sets and more.

  • Pay Over Time

    0% APR is available for 3 and 12- month financing.* See if you prequalify today.

  • Staff Picks

    Check out the Staff Picks collection. See the top products selected by our team.