Mason-Lite 43" See-Thru Gas B-Vent Firebox Kits
Mason-Lite 43" See-Thru Gas B-Vent Firebox Kits
Authorized Dealer
Call (844) 643-8500
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Description

The Mason-Lite 43" See-Thru Gas B-Vent Firebox Kits (model MGFPST43) is a pre-cast masonry firebox engineered specifically for B-vent vented gas operation, delivering the authentic look of a real brick fireplace with the convenience of gas. This model features a finished opening of 40" (W) x 30.5" (H) x 28" (D), a total unit height of 62.25", a 53" x 28" footprint and an approximate weight of 1726 lbs, so you can plan framing and structural support with confidence. Designed to vent through a 12 inch B-vent chimney, it opens up placement options in rooms where a traditional wood-burning chimney would be impractical or too costly. Lightweight refractory concrete blocks assemble quickly with high-temperature mortar, saving days of labor compared with a site-built firebox.
Pair the firebox with a matching Mason-Lite Virginiana decorative gas log set or burner for a complete, tested appliance, and dress the interior with cream, black or gold firebrick panels for a custom finish. The modular design is approved for combustible floor systems and installs easily in new construction or remodels. Every unit is backed by a limited lifetime warranty and is approved for installation in the USA and Canada.
What's Included
- 43" See-Thru Gas B-Vent Firebox Kits
- Standard Virginiana Log Set
- Remote control
Key Features
- Clean and Environmentally Friendly: Gas-burning fireplaces have lower outputs of carbon monoxide, pollutants, and particulate matter compared to wood-burners
- Convenient, No-Mess Operation: Free from sparks and long-burning embers, no chimney cleaning, no messy ashes or wood chips, no wood storage space needed
- 10" B-Vent Appliance with 24" Peterson Gas Logs
- Smaller Flue (10" instead of 14", 12" instead of 16" for See Thru) for reduced framing requirements. Architects love it
- Compliant with ANSI-Z 21.50 Vented Decorative Gas Appliances
- Handheld remote control for turning the gas on or off
- Electronic ignition with battery backup
- Safety shutoff feature for fail-safe operation
- Utilized industry-standard 10" B-Vent chimney (12" B-Vent for MGFPST43)
- Optional firebrick colors and patterns for an authentic fireplace
- Clean and environmentally friendly
- Lightweight construction
Specifications
| Brand | Mason-Lite |
|---|---|
| Model | MGFPST43 |
| Included Burner Width | 30" |
| Included Burner BTUs Natural Gas | 80,000 |
| Included Burner BTUs Propane | 80,000 |
| Finished Opening Dimension | 40" (W) x 30.5" (H) x 28" (D) |
| Total Unit Height | 62.25" |
| Foot Print | 53" x 28" |
| Weight with Burner | 1726 lbs. |
| Flue Diameter B-Vent | 12" ID |
| Clearance to combustibles | 0" |
| Installation Type | Flush Installation / Corner / Internal Wall / Full Projection |
| Certification | ANSI-Z 21.50 compliant |
| Warranty | Limited lifetime warranty |
| Category | Masonry Firebox Kits |
| Fuel Type | Natural Gas or Liquid Propane |
| Material | Pre-Cast Refractory Concrete |
| Made In | USA |

Documents & Files
- Mason-Lite Catalog
- Mason-Lite 4-page Brochure
- Mason-Lite Bi-fold Brochure
- Mason-Lite Linear Brochure
- Mason-Lite Gas B-Vent Brochure
- Mason-Lite Gas Vent Free Brochure
- Mason-Lite Custom Fireplace Brochure
- Opalescence Linear Burner Brochure
- Mason-Lite Burner Brochure
- Virginiana Gas Log Brochure
- Masonry Accessories Brochure
- Mason-Lite PureBurn Brochure
- Architectural Clay by MFI (Clay Chimney Tops)
- Shroud Brochure
- Mason-Lite Limited Lifetime Warranty
- Corner Installation
- Masonry Chimney Specifications
- Wood & Concrete Installation
- Mason-Lite Fireplace Stacking
- Standard Wood Burning (MFP33/39/44/49/63)
- MFP 75 Instruction Manual
- See-Thru (MFPST43)
- Regal Unit Instruction Manual (MFP72-RGL-MFP120-RGL)
- Wood Burning Clearance Mantel Guide
- Gas B-Vent (MGFP39/44/49)
- See-Thru Gas B-Vent (MGFPST43)
- LMFP Linear B-Vent Manual
- Linear Burner Riser Block Installation
- Vent Free Manual
- See Thru Vent Free Manual
- Virginiana Vent Free Burner Manual
- Opalescence Vent Free Burner Manual
- Firebrick Panel Instructions
- Masonry Arch
- Clay Flue Liner Instructions
- Pureburn Instructions
- Pureburn Electronic Ignition Installation
- Shroud Instructions
- Metal Base Installation
- Damper Block Instruction
- Chimney Sizing Chart
- Recessed Flooring Instructions
- CMU Base Layout
- Footing for Outdoor Fireplace
- Seismic Zoning Map
- Metal Base Spec Sheet
- Virginiana Standard Burner Manual
- Virginiana Jumbo Slim Gas Logs Installation Manual
- Virginiana Lucent Installation Manual
- Virginiana See Thru Burner Manual
- Opalescence LED Linear Burner Manual (For LMFP units with Trough)
- Opalescence Lumiere Instruction Manual
- Alpine Burner Manual (For LMFP units with Trough)
- Mason-Lite Minimum Fireplace Dimensions Flyer
- Masonry Chimney Instructions (with offset)
- Masonry Chimney Stack Example
- Masonry Chimney Anchor Plate Damper Instructions
- Mason-Lite Specification Sheet
- Pre-Installation Checklist
- Firebrick Per Unit
- Certified Mason-Lite Mason Certificate
- Homeowner Curing Instructions
Shipping & Returns
Shipping & Returns
Shipping Policy
We strive to make the ordering process as straightforward as possible. If you have any questions regarding your order, please contact us at +1 (844)-643-8500 or support@efireplacedirect.com during our regular business hours.
Order Confirmation
Upon placing your order, you will receive an order confirmation email. We will then verify that all items are in stock and available for shipment. If your order can be delivered within the advertised timeframe, it will be processed and sent to the warehouse for shipment.
If the expected delivery timeframe exceeds the advertised timeframe, we will contact you by email or phone to confirm the order and provide updated delivery information.
Order Processing
Orders are typically processed within 24–48 business hours after your payment has been successfully verified and approved. We make every effort to ship your items as quickly as possible.
Please note that shipping times refer to the time required for your order to arrive after it has been shipped and do not begin from the date the order is placed. Processing and shipping times exclude weekends and holidays.
If your order is urgent, we recommend contacting us at +1 (844)-643-8500 before placing your order so we can confirm product availability and the estimated shipping timeframe.
In rare cases, an item may be unavailable, backordered, or subject to an extended lead time. If this occurs, we will notify you as soon as possible.
Receiving an order confirmation does not guarantee final acceptance of your order. efireplacedirect reserves the right to accept or decline an order for any reason and may request additional information or verification before processing an order.
Order Shipment
Once your order has shipped, you will receive an email containing your tracking information, when tracking is available.
If you have not received tracking information within 7–10 business days of placing your order, please contact our customer service team at +1 (844)-643-8500 or support@efireplacedirect.com
Estimated Time of Arrival
Our standard delivery timeframe is generally 7–14 business days after shipment.
For custom-made or specially ordered products, delivery may typically take 4–12 weeks, depending on the product and manufacturer.
Delivery estimates are provided as guidelines and may vary depending on product availability, manufacturer lead times, carrier schedules, holidays, and other circumstances beyond our control.
If the estimated delivery timeframe for your order falls outside the expected delivery window, our customer service team may contact you with an updated estimate.
Areas Covered & Shipping Costs
Shipping rates and estimated delivery times advertised on our website apply to the contiguous United States (Lower 48 states) unless otherwise specified.
We offer free standard ground shipping on orders of $200 or more in our online catalog, subject to applicable product exclusions.
Shipping Rates
- Orders below $200: $70 flat-rate shipping
- Orders of $200 or more: Free standard ground shipping
Products specifically marked as eligible for free shipping qualify for the applicable free-shipping offer. Expedited shipping, special delivery services, or other upgraded shipping options may incur additional charges.
For shipping to Alaska, Hawaii, U.S. territories, or other locations outside the contiguous United States, additional shipping charges may apply, even when an item is listed as eligible for free shipping.
If additional shipping charges are required, we will contact you after your order is placed to confirm the shipping cost and arrange payment for any applicable additional charges.
We currently do not offer international shipping. However, customers may arrange delivery to a freight forwarder of their choice, subject to our shipping terms and carrier requirements.
Delivery Method
Standard shipping generally includes curbside delivery. This means the shipment is delivered to the curb or another accessible location near the delivery address, typically near the driveway or mailbox.
Customers are responsible for moving the product from the delivery location into their home and for any required assembly or installation.
Please review the product specifications and installation requirements before placing your order. Professional installation may be recommended or required for certain products.
Damaged or Missing Shipments
It is important to carefully inspect your shipment when it arrives.
- Before signing for a freight delivery:
- Inspect the packaging for visible damage.
- Confirm that all packages listed on the delivery receipt have been received.
- Take clear photos and videos of the shipment and packaging.
- If the package appears damaged, note the damage on the delivery receipt or bill of lading.
- If appropriate, refuse the shipment and clearly state "Refused due to damage."
If there is no visible damage to the outside of the packaging but you have not yet inspected the product, note "Subject to further inspection may contain concealed damage" on the delivery receipt before signing.
Failure to document visible damage or missing packages at the time of delivery may affect the ability to file a freight damage claim.
Concealed Damage
If you discover damage after opening the package and there was no visible damage to the exterior packaging, please keep all original packaging materials and contact us as soon as possible.
Please provide clear photos and videos showing:
- The damaged product
- All sides of the packaging
- Shipping labels
- Any visible damage to the box or packing materials
- The product packaging and protective materials
Damage claims should be reported within 2 business days of delivery so that we can work with the shipping carrier or manufacturer to determine the appropriate resolution.
Once we receive the required documentation, efireplacedirect will review the claim and, where applicable, work with the carrier or manufacturer to arrange a replacement or other appropriate resolution.
Customer Support
For questions about your order, product availability, shipping, delivery estimates, or damaged shipments, please contact:
Phone: +1 (844)-643-8500
Email: support@efireplacedirect.com
Return Policy
Order Cancellations
If you wish to cancel your order, please contact us as soon as possible. Most orders ship within 1–3 business days.
Your cancellation is only considered confirmed once you receive confirmation from us by phone or email.
Once an order has shipped, our Return Policy will apply. A restocking fee of up to 25% may apply to returned orders.
To request a cancellation, please contact us:
- Email: support@efireplacedirect.com
- Phone: +1 (844)-643-8500
Return Eligibility
At Modern Flames Shop, we strive to ensure your complete satisfaction with your purchase. If you need to return an item, please review the following return policy.
Items may be returned within 30 days of receiving the order for an exchange, store credit, or refund. Products must be unused, in new condition, and returned with their original packaging and included materials.
Return Policy
- Fireplace and accessory items must be returned within 30 calendar days of delivery.
- Products must be unused and in new condition.
- Items should be returned in their original packaging with all included materials.
- Shipping costs are non-refundable.
- A 25% restocking fee may be deducted from the refund.
- Refunds will be issued to the original form of payment.
- If a returned product is not eligible for a refund, we will notify you.
- Shipping charges are non-refundable and will be deducted from the refund amount.
Contact Us
If you have questions about cancellations, returns, exchanges, or refunds, please contact our customer support team:
Phone: +1 (844)-643-8500
Email: support@efireplacedirect.com
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