The L52FSD from Montigo
One fire, two rooms, 47 inches of it on each side — this is the wall you build a floor plan around. The Montigo L52FSD is the largest see-through Phenom: a 52-inch direct-vent gas fireplace at 40,000 BTU/hr on natural gas, with a 47" x 21-13/16" viewing area on each side, a 59" W x 39" H x 23-3/4" D framed opening, from $9,989, and a 15-year parts warranty on the firebox and burner. Four factory variants: natural gas or propane, standing pilot or electronic ignition.
Choose it if you want the biggest two-sided flame in the series — 47 inches of glass on each face — as a room divider or architectural centerpiece in a large space, with the contemporary Ice fireglass burner standard and your pick of piezo-lit standing pilot or Proflame 2 electronic ignition.
It is not right if you need side venting — the L52FSD is top-vent only, exiting the center of the unit, with at least 84 in. of vertical rise required; if you want blower fans, which are not available on this model at any price; if one side would face outdoors (see-through models cannot straddle indoor and outdoor spaces); or if you want halogen uplighting, which is not available on any see-through Phenom.
Specifications
Frame a rough opening 59 in. wide, 39 in. tall, and 23-3/4 in. deep. Side clearance to combustibles is 1 in., floor clearance zero, and a combustible shelf or header above the unit needs 30 in. It runs on natural gas (5.5 in. w.c. minimum inlet) or propane (11 in. w.c.) by variant. L52FSDN/L builds use a standing pilot with piezo igniter and manual Hi-Lo flame control; L52FSDNI/LI use SIT Proflame 2 electronic ignition on 120 VAC, 60 Hz, 6 A power. Spec-sheet efficiency runs 56.7–61.2% depending on fuel and ignition. This is a radiant unit — no fan option exists for this model.
L52FSD vs. the other see-through sizes and the single-sided 52s
The L42FSD (from $7,059) gives 34,000 BTU/hr with a 39-1/2-inch view per side and adds a multi-elbow side-vent option plus optional fans; the L38FSD (from $5,879) is 27,000 BTU/hr and may side-vent straight out the wall. If you only need one viewing side at this width, the single-sided 52s frame slightly wider at 52 x 43-3/4 in.: the Full Load P52DF ($7,849) with remote, fans, uplighting, and battery backup standard, or the Basic PL52DF ($5,949) — both on 5/10 venting with a rear multi-elbow option.
Answers to common questions
What venting does the L52FSD need, and is it in the box?
Vent pipe is sold separately and sized to your layout. The L52FSD uses 5 in. inner / 8 in. outer coaxial direct vent and is top-vent only — there is no side-vent option on this model, and the flue exits at the center of the unit. Wall terminations need at least 84 in. (7 ft) of vertical rise, which allows up to 60 in. of horizontal run; 96 in. of vertical allows up to 120 in. of horizontal, and roof terminations can run up to 32 ft above the unit. Beyond Montigo pipe, approved alternates include DuraVent 58DVA-series, ICC, MetalFab, Selkirk, and Flexmaster components — The Torch Guys stocks compatible DuraVent.
Will it work during a power outage?
It depends on the variant you order. The standing-pilot variants (L52FSDN natural gas, L52FSDL propane) use a SIT NOVA 820 valve lit by a push-button piezo igniter, so ignition does not depend on your home's electrical supply. The electronic-ignition variants (L52FSDNI, L52FSDLI) use SIT Proflame 2 and need 120 V power to light; the AF40BP battery backup tray (four AA batteries) is an available option worth adding if outages are common where you live.
Can it sit in a wall between indoors and outdoors?
No. Montigo is explicit that indoor see-through models cannot be installed as indoor/outdoor fireplaces, because air flows through both sides of the unit. Both faces must be in the same conditioned indoor space. There is one approved outdoor application — a fully protected outdoor room with the entire fireplace inside it and the 75% overhang coverage rules met — but never one side in, one side out. It also cannot be recessed into a wall cavity.
What’s included, what’s required, and what’s optional?
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Included in the box: the contemporary burner with Ice fireglass, glass on both sides with the required safety barriers, micro mesh screens, and manual Hi-Lo flame control.
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Required to complete the installation, purchased separately: the vent pipe and termination — Montigo pipe, or a manual-approved alternate from DuraVent, ICC, MetalFab, Selkirk, or Flexmaster.
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Optional: the multi-function remote and WiFi phone app control (electronic-ignition variants only — neither works with standing-pilot models), the AF40BP battery backup tray, surrounds, and glass media.
Is the Montigo warranty valid if I buy online?
It matters where you buy. Montigo's residential warranty is not applicable to equipment sold direct to consumer through internet or auction sites that are not authorized dealers. The Torch Guys is 1 of only 3 authorized Montigo e-commerce dealers in the United States, so buying here keeps your coverage intact: 15 years parts on the firebox, heat exchanger, and main burner (1 year labor), 15 years on Montigo venting, 10 years on Montigo terminations, and 1 year on most other components. Montigo requires licensed professional installation and annual service to maintain coverage. If you ever need a claim, we file it with Montigo on your behalf — call us at (410) 324-6322.
