The P52DF from Montigo
The Montigo P52DF is the largest single-sided Phenom, and it looks it: 47 inches of flame across a 52-inch direct-vent gas fireplace pushing 40,000 BTU/hr on natural gas or propane, with a 47" x 21-7/8" viewing area, a 52" W x 43-3/4" H x 24-1/2" D framed opening, a $7,849 price, and a 15-year parts warranty on the firebox and burner. Full Load tier: RX200 remote, fans, porcelain liner, halogen uplighting, and battery backup are standard.
Choose it if the room is big enough that a smaller fire would look apologetic. This is the widest single-sided flame Phenom builds, and the control package comes with it rather than after it — concealed Quartz firebead burner, six flame levels and fan speeds from the remote, and Smart Thermostat mode that modulates the flame toward the temperature you set.
It is not right if you wanted a simple straight-out-the-back vent — the P52DF cannot be rear vented straight through the wall; rear runs must be multi-elbow with at least 56 in. of rise. It is also not right for shallow walls (24-1/2 in. framing depth), tight chases (5/10 vent standard), recessed wall-cavity installs, or home-automation integration, which Montigo's control system does not support.
Specifications
Frame a rough opening 52 in. wide, 43-3/4 in. tall, and 24-1/2 in. deep. Unlike the smaller single-sided models, the 52 carries real clearances: 1 in. at the back, 2-1/2 in. at the sides from the main firebox body, 26 in. above on a top-vent install (12 in. rear-vent), and zero at the floor — though four-sided surrounds require a raised installation. Leave the supplied 7-1/2 in. standoffs in place. It runs on natural gas (5.5 in. w.c. minimum inlet) or propane (11 in. w.c.) by variant, lights with SIT Proflame 2 electronic ignition, and needs unswitched 120 VAC, 60 Hz power at 6 amps. Manual-rated efficiency (P.4.1-15) is 56% on natural gas and 59% on propane.
P52DF vs. the other Phenom sizes and tiers
Need less heat or a smaller wall? The P42DF ($6,969) gives 32,000 BTU/hr in a 42-inch opening with simpler 5/8 venting and true zero side clearance; the P38DF ($6,249) is 25,000 BTU/hr at 37-3/4 in. wide. Same size for less: the Basic-tier PL52DF ($5,949) keeps the 40,000 BTU/hr natural-gas rating, framing, and 5/10 venting but makes the remote, fans, liner, and battery backup optional — no uplighting or WiFi offered. For a room-divider flame, the see-through L52FSD (from $9,989) shows 47" x 21-13/16" on each side and vents on slimmer 5/8 pipe, top-vent only.
Answers to common questions
What venting does the P52DF need, and is it in the box?
Vent pipe is sold separately, and one constraint matters before you frame: the P52DF cannot be rear vented straight through the wall — rear-vent applications must be multi-elbow. It runs larger 5 in. inner / 10 in. outer coaxial pipe as standard; top or rear runs on 5/10 pipe need at least 56 in. of vertical rise and allow up to 20 ft of horizontal at that minimum. You can convert to 5/8 pipe with the RVA108 reducing collar only when the run has at least 8 ft of vertical rise off the top of 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?
Yes. Ignition is SIT Proflame 2 electronic (120 V), and the Full Load includes the AF40BP battery backup tray as standard — four AA batteries keep ignition working through an outage. The blower fans run on household power, so plan on radiant heat only until power returns.
Can I install it in a covered outdoor room?
It is certified as an indoor gas fireplace (CSA/ANSI Z21.88-2019 / CSA 2.33-2019). Montigo does permit single-sided Phenom models in protected outdoor locations, with conditions: the space must be sheltered from direct water, the overhang must extend at least 75% of the fireplace's height dimension across the front and both sides, every indoor clearance still applies, and the supplied safety screen must be used. Never operate it below 32°F. The fireplace cannot penetrate the building envelope and 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 concealed burner with Quartz firebeads, glass with the required safety barrier, the micro mesh screen, the RX200 multi-function remote, remote-controlled variable-speed fans, a black porcelain liner, halogen uplighting, and the AF40BP battery backup tray.
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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: surrounds in satin black or stainless steel, alternate media (speckled stones, driftwood, glass), and SIT-WIFI phone app control.
Can I run it from my phone or my smart-home system?
The Full Load ships with the SIT RX200 multi-function remote: on/off, six flame levels, six fan speeds, thermostat and Smart Thermostat modes, and a key lock. Optional SIT-WIFI phone app control is available for Full Load units. One honest caveat: the control system "Can not be used with home automation systems" — so no Alexa, Google Home, or Control4 integration.
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.
