Monessen Lumonessen Vent Free Burner — One Burner for the 18", 24" and 30" Mountain Oak, Mezmer and Mezmer Split Log Sets
One burner, three log sets, three lengths. The Monessen Lumonessen is the vent-free burner under every Classic Series log set — Mountain Oak, Mezmer or Mezmer Split in 18", 24" or 30" — and it is the same LUM-VF burner whichever logs you put on it: 38,000 BTU/hr maximum on natural gas or propane, an ODS safety pilot lit by a piezo, and no electricity anywhere in it. Choose the variable manual control or the millivolt valve with its on/off switch and Hi/Lo knob, which also takes an optional remote, wall switch or thermostat. The logs are sold separately; the grate, two bags of volcanic rock, the rock wool and the shutoff valve with flex connector are in the box. from $609, with a 5-year parts warranty on the burner.
Choose it if you have a masonry or factory-built wood fireplace — or a Monessen Exacta, Attribute or Lo-Rider vent-free firebox — and want the affordable Classic Series route to a vent-free fire: one burner that fits the 18" sets in a 25"-wide hearth, the 24" sets in 29", the 30" sets in 33", all at 13" deep and 17" high by the manual's hearth table, and the chance to change the logs later without changing the burner. Pick the millivolt control if you want a remote or thermostat now or later; pick manual if you want the simplest possible knob-and-piezo set.
It is not right as a primary heat source — Monessen lists it as a supplemental room heater or decorative appliance, and an unvented burner puts moisture into the room. It ships with no logs, so it is not a complete fire on its own, and it takes only the Monessen Mountain Oak, Mezmer and Mezmer Split sets. It cannot go in a bedroom or bathroom, in a factory-built fireplace whose instructions exclude unvented gas logs, or behind glass doors that will be closed while it runs; a door frame or recessed hearth standing more than 3" in front of the set is not recommended at all. The room has to give it 50 cubic feet for every 1,000 BTU/hr of gas appliances in it, and above 2,000 feet the input is derated 4% for each 1,000 feet of elevation measured from SEA LEVEL, so 12% at 3,000 feet.
Specifications
The minimum hearth for the burner with its logs is 25" wide at the front, 13" deep and 17" high with a 17-1/2" rear width for an 18" log set; a 24" set needs 29" at the front and 19-1/2" at the rear, a 30" set 33" and 25-1/4", at the same depth and height. The manual's restrictive- barrier table lists 14" of depth with no barrier and 16" where a glass-door frame or recessed hearth stands up to 3" in front of the set, so plan on 14" for a comfortable fit. Sidewalls stay 9" from the side of the fireplace opening and the ceiling 42" above it; the wall directly above the opening must be heat-resistant material (slate or marble at least 1/2" thick) for 12" — with 8" to 12" you extend the material or add a hood, with under 8" you extend to at least 8" and add a hood. Only where that material runs 12" or more and no hood is fitted does a combustible mantel projecting 10" or less sit 28" above the opening, whatever its depth; with the hood fitted it sits 8" to 26" by projection — per Figures 3.5 and 3.6 on page 11 of the manual. The burner sits 1-3/8" above carpet that comes within 14" of the fireplace, or on 14" of slate or marble. Inlet pressure runs 5" to 10.5" w.c. on natural gas and 11" to 13" w.c. on propane; each burner is built for one gas and cannot be converted in the field. If the fireplace cannot meet the vent-free clearances, the set is installed vented with the damper clamped open, and in a Monessen vent-free firebox the firebox's own clearances govern.
Features
- One burner size carries every Classic Series log set — Mountain Oak, Mezmer or Mezmer Split in 18", 24" or 30" — so you pick the burner by fuel and control, then the logs by the fireplace
- 38,000 BTU/hr maximum input on natural gas or propane, turned down to 19,000 (manual, NG), 27,000 (millivolt, NG) or 31,000 BTU/hr (propane) at low
- No electricity at all — a piezo lights the pilot on both controls; the millivolt valve powers itself and accepts an on/off or thermostat remote, a wall switch or a thermostat
- Vent free with an ODS safety pilot, listed to ANSI Z21.11.2 as an unvented room heater and to ANSI Z21.60 as a vented decorative log set for a masonry fireplace, UL127 factory-built fireplace or listed vent-free firebox
- Ships with its grate, two bags of crushed volcanic rock, rock wool, anchoring screws and a 1/2" T-handle shutoff with flex connector already on the valve
- Monessen's replacement for the PH log series, in production since 2023, with a 5-year parts warranty on the burner
Answers to common questions
Does it need a chimney, a vent or electricity?
No to all three, on every variant. The Lumonessen is an unvented room heater that burns room air through an ODS safety pilot, so it runs with the fireplace damper closed against a damper stop that keeps a 29 square inch opening — the stop is not in the carton, so add Monessen's damper clamps if your fireplace has a damper. It is also listed as a vented decorative log set: if your fireplace can't meet the vent-free wall or mantel clearances, or your local code allows only vented gas logs, it is installed with the damper clamped fully open instead (the manual's vented note names the millivolt models — confirm with your installer for a manual-control set). Nothing in it uses house current: a piezo lights the pilot and the millivolt valve powers itself. Either way the room must give it 50 cubic feet for every 1,000 BTU/hr of gas appliances in it.
Which log sets fit, and do I have to buy one?
Yes — the burner ships without logs, and it takes Monessen's three Classic Series sets: Mountain Oak, Mezmer and Mezmer Split, each made in 18", 24" and 30". Every length sits on this same burner, so you size the logs to the fireplace and the burner never changes: an 18" set needs a hearth 25" wide at the front, 13" deep and 17" high with 17-1/2" across the back; a 24" set 29" front and 19-1/2" rear; a 30" set 33" front and 25-1/4" rear. Plan on 14" of depth if you can, and 16" where a glass-door frame or a recessed hearth stands up to 3" in front of the set. Monessen's own vent-free fireboxes pair the 18" sets with the Exacta 32 and Attribute 32, the 24" sets with the Exacta 36, Attribute 36 and Lo-Rider 36, and the 30" sets with the Exacta 42, Attribute 42 and Lo-Rider 42. The three log sets are below the cart on this page.
How close can a mantel or the ceiling be?
The clearances are the same for all four burners. The ceiling must be at least 42" above the top of the fireplace opening and combustible sidewalls at least 9" from its sides. The wall directly above the opening has to be heat-resistant material — slate or marble at least 1/2" thick — and how much of it decides the rest: 12" or more needs no hood; 8" to 12" means extending it to 12" or adding a hood; under 8" means extending to at least 8" and adding a hood. Those two numbers set which mantel schedule you may use. With 12" or more of heat-resistant material and no hood, a combustible mantel projecting 10" or less must sit at least 28" above the opening — there is no shallower allowance without a hood. With the hood fitted — which is what the 8"-to-12" and under-8" cases call for — it needs 8", 14-1/2", 18-5/8", 22-1/2" and 26" for 2-1/2" to 12" of projection, so a hood is what buys back the height. Figures 3.5 and 3.6 on page 11 of the manual draw each case. Monessen's CABL adjustable canopy is the hood. If your fireplace can't meet them the set runs as a vented log set with the damper open; in a Monessen vent-free firebox the firebox's own clearances apply. Send us your mantel depth and height and we'll check it against the figure.
What’s included, what’s required, and what’s optional?
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Included in the box: Lumonessen vent-free burner assembly with its grate; Two bags of crushed volcanic rock and rock wool ember material; 1/2" T-handle manual shutoff valve and flexible gas connector on the valve inlet, two anchoring screws, installation/owner's manual; ODS safety pilot with piezo ignitor; on/off switch and Hi/Lo knob on the millivolt valve, variable Hi/Low knob on the manual control.
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Required to complete the installation, purchased separately: Log set - a Monessen Mountain Oak, Mezmer or Mezmer Split set in 18", 24" or 30"; the burner ships without logs and takes only these sets; Gas line - a natural gas or propane line to the fireplace run by a qualified installer, with an external regulator on propane and on any natural-gas supply above 1/2 psig; A fireplace or firebox to house it - a solid-fuel masonry fireplace, a UL127 factory-built fireplace or a listed vent-free firebox whose hearth meets the minimum for the log size chosen.
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Optional: C-CLAMP damper clamps (carton of 6) - only if the fireplace forces you to run it vented. Vent-free, the burner works without them and the damper stays under your control; if the wall or mantel clearances cannot be met the manual sends you to a vented installation with the chimney and damper open, and there the clamps are required; For the millivolt models: RCB on/off remote, TSST thermostat remote with the TS bulb sensor, a wall switch or thermostat; RRCM insulated receiver cover; CABL adjustable canopy where the wall above the opening needs a hood — the burner operates fully without them.
Will it work in a power outage?
Yes, on every variant — nothing in the Lumonessen uses electricity. The manual control is a knob and a piezo ignitor; the millivolt valve lights from the same piezo and runs on its own thermopile, so a dark house still gets a fire. Only a battery remote, if you add one, needs batteries.
Manual or millivolt — which control should I pick?
Both light the same 38,000 BTU/hr burner with a piezo-lit standing pilot; they differ in what you can add. The manual control (LUM-VF-NM / PM) is one knob: light the pilot, turn it to HIGH, then anywhere between HI and LOW — no switch, no wiring, nothing to add later. The millivolt control (LUM-VF-NV / PV) has an on/off switch and a Hi/Lo knob, and its valve terminals take an optional wall switch, a thermostat (unvented installations only) or a remote — the RCB on/off remote or the TSST touch-screen thermostat remote with the TS sensor, both below the cart. On natural gas the millivolt model's low setting is 27,000 BTU/hr against the manual model's 19,000; on propane both turn down to 31,000.
How is the Lumonessen different from Monessen's Natural Blaze and Glow Getter burners?
It is the Classic Series burner — Monessen's "easy and affordable" route — and the one that replaced the older PH log series. The Lumonessen comes in one size that carries every Classic Series set, in manual or millivolt control, at up to 38,000 BTU/hr. The Deluxe Series Natural Blaze (Berkley Oak, Highland Oak, Stony Creek, Beachcomber) and Glow Getter (Dynamo, Moxie, Charisma) burners are sized to their log sets, rate up to 37,000 BTU/hr on natural gas (36,000 on propane) in the 24" size and add an electronic IntelliFire ignition option; their log sets do not fit the Lumonessen, and the Mountain Oak, Mezmer and Mezmer Split sets do not fit them.
Does buying from The Torch Guys affect my Monessen warranty?
No. HHT's warranty covers Monessen products bought through an authorized dealer, and The Torch Guys is one — we register the burner and, if you ever need to claim, we deal with the manufacturer on your behalf. The vent-free burner carries 5 years on parts, purchased accessories such as the remotes 1 year, and the coverage transfers to a later owner of the home. Keep your invoice and the model number from the rating plate in the control area; we hold the rest on file.
