Superior VRT3100 Series Vent-Free Gas Firebox
Superior VRT3136 36" Clean-Faced Vent-Free Gas Firebox
The Superior VRT3136 is a 36-inch clean-faced, heat-circulating vent-free gas firebox enclosure designed for a separately selected compatible vent-free gas log heater. It provides a 35-inch interior front width, 24-inch interior height, factory-supplied heat-deflection hood, mesh fire screens, multiple interior liner options, and optional blower capability for qualifying built-in fireplace installations.
Model
VRT3136
Nominal Size
36"
Opening Height
24"
Configuration
Firebox Only
Design
Clean Face
Construction
Heat-Circulating
Max Heater Input
40,000 BTU/hr
Warranty
20-Year Limited
Important: Firebox Enclosure Only
The Superior VRT3136 is not a complete gas fireplace system. A compatible vent-free gas log heater, burner system, natural gas or propane configuration, and applicable controls must be selected separately.
40,000 BTU/hr Maximum Heater Input
The vent-free room heater installed in the VRT3136 must be listed to ANSI Z21.11.2 and must not exceed 40,000 BTU/hr.
36" Clean-Faced Vent-Free Fireplace Foundation
The VRT3136 is designed for homeowners, builders, contractors, and fireplace professionals who want a flexible built-in vent-free firebox without being locked into one factory-selected gas-log presentation.
The clean-face design creates a streamlined front opening, while the heat-circulating construction allows room air to move through the fireplace cabinet. If additional air circulation is desired, compatible blower kits can be added.
The separately selected gas-log system determines the fuel type, BTU input, flame presentation, ignition, control system, and log style.
Superior VRT3136 at a Glance
Brand
Superior Fireplaces
Product Type
Universal Vent-Free Gas Firebox
View Style
Front-View / Single-Sided
Heat Circulation
Heat-Circulating Design
Gas Log System
Sold Separately
Is the Superior VRT3136 Right for Your Project?
Best For
- Projects requiring a 36" built-in vent-free firebox.
- Homeowners wanting a clean-face front-view fireplace.
- Installations using a separately selected vent-free gas-log heater.
- Projects needing a 35" interior front width and 24" interior height.
- Buyers wanting a choice of fiber or refractory interior treatments.
- Projects where optional forced-air circulation is desired.
- Installations where an outside-air kit may be useful.
- Buyers wanting flexibility across multiple Superior gas-log styles.
Consider Another Fireplace If
- You want a complete gas fireplace package with burner and logs included.
- Your selected heater exceeds 40,000 BTU/hr.
- Your selected heater does not meet the available interior dimensions.
- Your project requires direct-vent or conventional vented operation.
- You intend to burn wood or solid fuel.
- You need installation in a bathroom.
- You cannot satisfy the required combustion-air or clearance provisions.
What's Included with the VRT3136?
Included
- Superior VRT3136 firebox enclosure
- Factory-supplied heat-deflection hood
- Mesh fire screens
- Heat-circulating clean-face construction
- Textured powder-coat finish
- Selected liner / floor configuration
Sold Separately / Optional
- Vent-free gas log heater and burner
- Natural gas or propane configuration
- Gas-log controls
- Decorative twin-pane screen
- FBK-100 blower
- FBK-200 blower
- Outside-air kit
VRT3136 Appliance Dimensions
| Nominal Width |
36" |
| Opening Height |
24" |
| Overall Width |
41-3/4" |
| Overall Height |
37-1/4" |
| Overall Depth |
20" |
Dimension distinction: Appliance dimensions, framing dimensions, and interior firebox dimensions serve different purposes and should not be used interchangeably.
VRT3136 Interior Firebox Dimensions
Superior provides the interior dimensions specifically to help determine whether a selected gas-log system will physically fit.
| Interior Front Width |
35" |
| Interior Rear Width |
23-1/4" |
| Interior Depth |
17-3/8" |
| Interior Height |
24" |
Gas-log compatibility: Compare all four interior measurements with the exact minimum fireplace dimensions required by the selected vent-free gas-log heater.
VRT3136 Framing Requirements
| Framing Width |
42-1/4" |
| Framing Height |
40-1/4" |
| Framing Depth |
20-1/2" |
Construction planning: Verify final framing, corner installation, finishing, mantel, gas-line, electrical, and accessory requirements against the manufacturer installation manual before enclosing the firebox.
Do not scale product images or diagrams. Manufacturer illustrations are not scaled construction drawings.
Interior Liner Options
Back Bay Brown Fiber Liner
The Back Bay Brown ceramic-fiber liner creates a warm masonry-inspired backdrop for the selected vent-free gas-log presentation.
White Stacked Refractory
The White Stacked refractory configuration creates a lighter stacked-masonry appearance inside the firebox.
Variant note: Exact shipping weight and interior construction depend on the selected VRT3136 configuration.
Compatible Superior Vent-Free Gas Log Styles
Superior identifies several vent-free gas-log presentations for the VRT3100 Series. Exact compatibility still depends on the selected size, fuel configuration, burner, controls, and minimum firebox dimensions.
| Log Style |
Series |
Log Material |
| Crescent Hill |
Double-Flame |
Concrete |
| Crescent Hill HD |
Double-Flame |
High-Density Fiber |
| Golden Oak |
Double-Flame |
Ceramic Fiber |
| Boulder Mountain |
Glow-Ramp |
Concrete |
| Rugged Stack |
Triple-Flame |
Concrete |
| Wild Timber |
Triple-Flame |
Concrete |
Family-level compatibility is not model-level approval. Verify the exact gas-log heater against the VRT3136 dimensions and 40,000 BTU/hr maximum before ordering.
Superior Gas Log Style Examples
Crescent Hill
Concrete logs from Superior's Double-Flame Series.
Crescent Hill HD
High-density fiber logs from the Double-Flame Series.
Golden Oak
Ceramic-fiber logs from the Double-Flame Series.
Boulder Mountain
Concrete logs from Superior's Glow-Ramp Series.
Rugged Stack
Concrete logs from Superior's Triple-Flame Series.
Wild Timber
Concrete logs from the Triple-Flame Series.
Required Heat-Deflection Hood
The VRT3136 includes a factory-supplied heat-deflection hood.
The hood is required for all VRT3100 installations. Keep the factory-supplied hood installed and do not substitute a hood supplied with a separate decorative vent-free room heater.
Heat-Circulating Design & Optional Blower
The VRT3136 uses a heat-circulating cabinet. Room air moves through the circulation passages around the firebox and can be assisted by an optional blower.
FBK-100
Optional standard single-speed blower.
FBK-200
Optional variable-speed blower with wall-mounted variable-speed control.
Electrical requirement: Optional blower equipment requires a 120 VAC, 60 Hz, single-phase supply. Plan electrical service before the firebox is enclosed if a blower will be used now or later.
Optional Decorative Twin-Pane Screen
Architectural Front Upgrade
A precision-cut decorative twin-pane screen in a textured iron finish is available as an optional visual upgrade.
Optional Outside-Air Kit
An optional outside-air gate and duct kit is available for the VRT3100 Series.
- Includes an air-gate assembly.
- Includes 4-inch-diameter duct.
- Includes termination hood.
- Only one outside-air kit is required.
- The kit is installed on the right side of the fireplace according to Superior's instructions.
Vent-Free Operation & Combustion Air
A compatible vent-free heater installed in the VRT3136 uses room air for combustion.
The installation space must therefore provide adequate combustion and ventilation air according to Superior's calculations and applicable codes.
Vent-free does not mean air-free. If the space does not provide the required indoor-air volume, additional ventilation must be provided using an approved method.
Installation & Clearance Considerations
Ceiling Clearance
Minimum 40" above the top of the firebox opening.
Mantel & Trim
Clearances vary according to projection depth and position.
Side-Wall Clearances
Follow the applicable manufacturer installation diagram.
Required Hood
The factory hood must remain installed.
Gas Supply
Gas-line access is provided from either side of the firebox.
Combustion Air
Room-air and ventilation requirements must be verified before installation.
Do not estimate clearances from photographs. Use Superior's dimensional and clearance diagrams for the exact finished installation.
Floor & Hearth Requirements
The VRT3136 may be installed on an appropriate combustible surface.
If installed over carpeting, vinyl tile, or another combustible floor covering other than wood flooring, a metal or wood panel must cover the full width and depth of the appliance.
Hearth extension: Superior states that a hearth extension may be used but is not required for the VRT3100 Series firebox.
Gas-Line Planning
Gas piping must be properly sized and installed for the selected heater and fuel configuration.
Superior recommends that gas-line sizing and routing be completed by an appropriately qualified professional such as a licensed plumber or gas fitter.
Plan before finishing: Gas-line access is available from either side of the firebox, and the gas supply should be installed before the VRT3136 is enclosed in the finished wall.
Location & Safety Considerations
- Do not install the VRT3136 in a bathroom.
- Do not install these built-in vent-free fireboxes in recreational vehicles.
- Keep the installation away from high-traffic areas where practical.
- Keep furniture, draperies, clothing, and other combustible materials away from the operating heater.
- Do not obstruct the front opening or heat-circulating air passages.
- Avoid strong drafts that can alter the burner flame pattern.
- Do not burn wood or solid fuel in the firebox.
- Installation, gas work, electrical work, and service should be performed by appropriately qualified professionals.
VRT3136 Variant Shipping Information
| Variant |
Shipping Weight |
Shipping Volume |
| VRT3136F |
125 lbs. |
20 cu. ft. |
| VRT3136WS |
150 lbs. |
20 cu. ft. |
Variant-specific data: Shipping weight differs according to the selected interior configuration.
Complete Superior VRT3136 Specifications
| Manufacturer |
Superior Fireplaces |
| Series |
VRT3100 |
| Model |
VRT3136 |
| Product Type |
Universal Vent-Free Gas Firebox |
| Installation Type |
Built-In |
| Vent Type |
Vent-Free |
| View Style |
Front-View / Single-Sided |
| Face Style |
Clean Face |
| Heat Circulation |
Heat-Circulating Design |
| Nominal Size |
36" |
| Opening Height |
24" |
| Framing Width |
42-1/4" |
| Framing Height |
40-1/4" |
| Framing Depth |
20-1/2" |
| Interior Front Width |
35" |
| Interior Rear Width |
23-1/4" |
| Interior Depth |
17-3/8" |
| Interior Height |
24" |
| Overall Width |
41-3/4" |
| Overall Height |
37-1/4" |
| Overall Depth |
20" |
| Maximum Approved Heater Input |
40,000 BTU/hr |
| Approved Gas Log Standard |
ANSI Z21.11.2 Listed Vent-Free Gas Log Room Heater |
| Firebox Enclosure Listing |
ANSI Z21.91 |
| Report Number |
F14-168 |
| Heat-Deflection Hood |
Included and Required |
| Mesh Fire Screens |
Included |
| Finish |
Textured Powder Coat |
| Interior Options |
Back Bay Brown Fiber / White Stacked Refractory |
| Gas Log Set |
Sold Separately |
| Optional Blower |
FBK-100 or FBK-200 |
| Blower Electrical Supply |
120 VAC, 60 Hz, Single Phase |
| Outside-Air Kit |
Optional |
| Decorative Screen |
Optional Twin-Pane Screen |
| Hearth Extension |
Optional / Not Required |
| Bathroom Installation |
Not Permitted |
| Solid-Fuel Use |
Not Permitted |
| Warranty |
20-Year Limited Warranty |
Flame Authority Expert Recommendation
Choose the Superior VRT3136 when your project calls for a 36" clean-faced vent-free firebox and you want the flexibility to choose the gas-log style, burner, fuel type, control system, liner, and accessories separately.
Its 35" interior front width, 23-1/4" rear width, 17-3/8" depth, 24" height, required factory hood, included mesh screens, optional blower capability, multiple liner choices, and 40,000 BTU/hr maximum heater input make it a flexible platform for qualifying vent-free installations.
The most important buying step is verifying the 42-1/4" × 40-1/4" × 20-1/2" framing space, exact gas-log heater dimensions, BTU input, fuel type, controls, combustion-air requirements, gas-line plan, optional blower wiring, clearances, and local vent-free requirements before construction.
Need Help Choosing the Right Configuration?
Need help determining whether the Superior VRT3136 fits your project or choosing a compatible vent-free gas-log configuration?
Talk to a Flame Authority expert at +1-800-923-4556 or email support@flameauthority.com for product-selection assistance.
Official Manufacturer Resources
Superior VRT3100 Series Product Brochure
Manufacturer overview covering VRT3100 fireboxes, liner options, accessories, and product features.
Superior VRT3100 Series Vent Free Gas Logs Brochure
Manufacturer information covering compatible Superior vent-free gas-log families and burner styles.
Superior VRT3100 Series Smart Sheet
Quick-reference model, dimensional, liner, accessory, and configuration information.
Superior VRT3100 Series Installation & Operation Manual
Manufacturer framing, combustion-air, hood, gas-line, electrical, clearance, floor, operation, and safety requirements.
Superior VRT3100 Series Specification Sheet
Manufacturer appliance, framing, interior, listing, and technical dimensional information.
Superior VRT3136 FAQs
What is the Superior VRT3136?
The VRT3136 is a 36-inch clean-faced, heat-circulating vent-free gas firebox enclosure designed for a separately selected compatible vent-free gas-log heater.
Does the Superior VRT3136 include gas logs?
No. The VRT3136 is the firebox enclosure only. The compatible vent-free gas-log heater, burner, fuel configuration, and controls are sold separately.
What are the framing dimensions for the VRT3136?
The manufacturer specifies 42-1/4" W × 40-1/4" H × 20-1/2" D.
What are the interior dimensions of the VRT3136?
The interior measures 35" front width × 23-1/4" rear width × 17-3/8" depth × 24" height.
What is the maximum BTU input allowed in the VRT3136?
The separately installed vent-free gas-log heater must not exceed 40,000 BTU/hr.
What type of gas logs can be used?
Use a compatible ANSI Z21.11.2-listed vent-free gas-log room heater that fits the VRT3136 and satisfies all applicable installation requirements.
Which Superior gas-log styles are shown for the VRT3100 Series?
Superior identifies Crescent Hill, Crescent Hill HD, Golden Oak, Boulder Mountain, Rugged Stack, and Wild Timber as VRT3100 Series gas-log presentations.
Does the VRT3136 require a chimney?
No conventional chimney is used for its approved vent-free configuration, but adequate combustion and ventilation air are still required.
Does the VRT3136 include a hood?
Yes. The factory-supplied heat-deflection hood is included and required for all VRT3100 installations.
Does the VRT3136 include fire screens?
Yes. Mesh fire screens are included. An optional decorative twin-pane screen is available separately.
Can a blower be added?
Yes. The VRT3136 supports optional FBK-100 and FBK-200 blower configurations.
Does the optional blower require electricity?
Yes. Optional blower equipment requires a 120 VAC, 60 Hz, single-phase electrical supply.
Is an outside-air kit available?
Yes. Superior provides an optional outside-air gate and duct kit for applicable VRT3100 installations.
What interior liner options are available?
The supplied VRT3100 information shows a Back Bay Brown fiber liner and White Stacked refractory liner.
Can wood be burned in the VRT3136?
No. The VRT3136 is designed for an approved vent-free gas-log room heater and must not be used to burn wood or other solid fuel.
Can the VRT3136 be installed in a bathroom?
No. Superior's installation information states that VRT3100 Series fireboxes must not be installed in a bathroom.
Can it be installed over combustible flooring?
It may be installed on an appropriate combustible surface. Over carpet, vinyl tile, or certain other combustible coverings, a metal or wood panel must cover the full appliance footprint.
Is a hearth extension required?
No. Superior states that a hearth extension may be used but is not required for the VRT3100 Series.
What is the minimum ceiling clearance above the opening?
The ceiling must be at least 40 inches above the top of the firebox opening. Other mantel, trim, side-wall, and combustible clearances also apply.
Who should install the VRT3136?
Gas, electrical, installation, and service work should be completed by appropriately qualified professionals following Superior's instructions and applicable codes.
What warranty does the Superior VRT3136 have?
The VRT3100 Series carries a 20-year limited warranty, subject to the manufacturer's component-specific terms, exclusions, and installation requirements.
Before You Order
Confirm Before Purchase
- You specifically need the Superior VRT3136.
- Your project can accommodate 42-1/4" W × 40-1/4" H × 20-1/2" D framing.
- You understand the product is a firebox enclosure only.
- You have selected a compatible ANSI Z21.11.2 vent-free gas-log heater.
- The selected heater does not exceed 40,000 BTU/hr.
- The heater fits the 35" front width, 23-1/4" rear width, 17-3/8" depth, and 24" height.
- You have confirmed natural gas or propane configuration.
- You can meet all combustion-air and clearance requirements.
- You will retain the factory-supplied heat-deflection hood.
- You have planned the gas line before enclosing the fireplace.
- If adding a blower, electrical service will be planned before enclosure.
- You have confirmed the desired liner and accessory configuration.
Do Not Assume
- That gas logs or a burner are included.
- That every 36" gas-log system will fit.
- That nominal log size alone establishes compatibility.
- That the firebox itself produces 40,000 BTU/hr.
- That the factory hood is optional.
- That vent-free operation eliminates combustion-air requirements.
- That wood or solid fuel can be burned in the firebox.
- That bathroom installation is permitted.
- That a blower can be added later without electrical planning.
- That all VRT3136 variants have the same shipping weight.
- That manufacturer photographs or drawings can be treated as scaled plans.
Final planning check: Use the Superior VRT3100 Installation & Operation Manual, Specification Sheet, Smart Sheet, and documentation for the exact selected gas-log heater to verify framing, interior fit, BTU input, fuel configuration, controls, combustion air, required hood, clearances, gas supply, electrical provisions, liner selection, accessories, and final installation before construction.
