Atosa ATCB-24-NG 24-inch Natural Gas Lava Rock Charbroiler

Who the ATCB-24 Is Built For

The ATCB-24 puts Atosa's lava rock grilling in the smallest footprint: two 35,000 BTU burners under a bed of lava briquettes, 70,000 BTU total, on natural gas. Same 24" width, same grates and same work area as the radiant ATRC-24, but the rock changes how the grill cooks. Drippings land on hot rock, flare and smoke, and that smoke goes back into the food.

That makes it the right small grill for menus where char and smoke are the selling point: a taqueria grilling carne asada and pollo asado, a Latin or Mediterranean counter running kebabs and skewers, a bar where the burger is "flame-grilled" on the menu, or a steak special program in a kitchen that does not need a full steakhouse line. At 136.9 lb it is 20.1 lb heavier than the radiant 24", so confirm your stand or counter rating.

The tradeoff for flavor is upkeep: lava rock has to be kept evenly spread, turned and eventually replaced. If you want low maintenance or propane from the factory, the radiant ATRC-24-NG and ATRC-24-LP are the alternatives. If you need a third zone of lava rock, step up to the ATCB-36.

Common fits for this model:

• Taquerias and Latin grills (carne asada, pollo asado)
• Kebab, skewer and Mediterranean counters
• Bars with a flame-grilled burger
• Small steak and chop special programs

Is the ATCB-24 the Right Size?

The ATCB-24 is 24" wide with two 12" zones and about 483 sq in of grate. Every Atosa charbroiler uses the same 12" zone, so sizing comes down to how many zones your busiest hour needs at the same time: one to sear, one to cook through, and ideally one to hold.

How much fits on the 24" grate

Estimated full-grate counts with room to flip. In real service, plan on about two-thirds to three-quarters of these numbers, because a zone is usually kept for holding or cooler cooking.

Compare the other lava rock sizes

ATCB-24 vs. ATRC-24-NG: Lava Rock or Radiant

The ATCB-24 and the radiant ATRC-24-NG share the same burners, BTU, grates, work area and footprint. The difference is what sits between the flame and the food. Lava rock holds heat and catches drippings, which flare and smoke back into the food for a heavier char. Radiants give cleaner, more even heat and less flare-up, with less upkeep.

Zones and Grates on the ATCB-24

Each 12" section has its own 35,000 BTU burner, standby pilot and manual control. The knob sets the flame size, not a temperature, so cooks control results by zone: turn one up to sear, another down to cook through, and keep one low or off to rest and hold. Turning off zones you are not using during slow periods is also the easiest way to save gas.

Reversible, adjustable grates. Per Atosa's manual, one side of each cast iron grate has a grease trough and the other side is flat. Use the trough side up for fatty foods like burgers, ribeyes and chicken thighs, so fat drains to the catch tray instead of flaring. Use the flat side for fish, vegetables and delicate items. The grates can also be angled to move grease toward the trough or to cook a little cooler at the high end.

Carne Asada on the ATCB-24

Carne asada is the dish lava rock was made for. Thin, well-marinated beef cooked fast over very high heat, with the marinade and fat dripping onto hot rock and flaring back into the meat.

• The cut. Skirt steak (outside skirt if you can get it) is the classic: thin, loose-grained and full of flavor. Flank steak and thin-sliced sirloin flap also work.
• The marinade. Citrus (orange and lime), garlic, chiles, cilantro and oil. Acidic marinades soften texture over time, so many kitchens limit very acidic marinades to a few hours to overnight. Pat off excess marinade before grilling; pooled liquid steams instead of searing and causes heavy flare-ups.
• The heat. Run one zone at full fire. Thin skirt often needs only a few minutes per side; thicker flank takes longer. Cook by thermometer and appearance, not by the clock: well-charred outside, then pull at your house doneness.
• Manage flare-ups. Lava rock flares more than radiants. A little flare gives the char; sustained flame blackens. Move the meat to the cooler zone for a moment rather than spraying water on a gas grill.
• Rest and slice. Rest a few minutes, then slice thinly against the grain. With skirt steak, the grain runs across the width of the strip, so cut the strip into sections first, then turn each section and slice across the fibers.
• Pollo asado follows the same pattern with boneless thighs: high heat for char, cooler zone to finish, 165°F internal.

The second 12" zone is where tortillas warm, onions and peppers char, and cooked meat holds for a few minutes during a rush.

Seasoning a Lava Rock Grill

A lava rock grill has two things to season: the cast iron grates and, in a sense, the rock bed itself.

First use. Atosa's manual says to wipe the unit with a mild detergent before first use, spread the lava rock evenly on the bottom frame (pieces about 3 to 5 cm), then preheat. The first heat-up smokes as factory protective oil burns off; Atosa says it clears after about an hour at maximum. Run that burn-in with the hood on and no food on the grates.

Grates. After the burn-in, clean the grates, coat them with cooking oil and run the grill open for 45 minutes, uncovered. That is Atosa's seasoning step from the cleaning table, and it is the same step you repeat after deep cleaning. Use a thin coat of a high smoke point oil; thick oil turns sticky instead of hardening.

The rock bed. New lava rock picks up flavor from the first few services as drippings soak in and burn off. That is part of the character of a lava rock grill. Over time, though, the rock becomes saturated, flares constantly and gives off acrid smoke. Turning the rock (clean side up) extends its life; replacing it restores clean flavor.

Daily maintenance seasoning. After the end-of-day brush and scrape, a light wipe of oil on the warm grates keeps the seasoning building. A grate that looks dry, gray or spotted with rust needs a full re-season.

Preventing and Fixing Rust on Cast Iron Grates

Cast iron rusts whenever it is left wet or bare. On a lava rock grill the risk spots are the grates and the bottom frame under the rock.

• Why it happens: soaking grates in the sink, putting them back wet, steam from cleaning, a long shutdown in a humid kitchen, or seasoning that has burned off from repeated high heat without re-oiling.
• Light surface rust: wire-brush it off, wipe the grates clean, dry them on the heat, then re-season with Atosa's 45-minute oil burn.
• Heavy rust: scrub down to bare metal with a wire brush or scraper, rinse only if needed, dry immediately and completely on the heat, and season in several thin coats. Replace grates that are cracked, warped or deeply pitted.
• Prevention: keep the grates seasoned, dry them on the heat after any cleaning, and oil them lightly before a shutdown. For long closures, Atosa's manual says to wipe the surfaces with a soft cloth and keep the unit in a well-ventilated area.

Do not hose down or pressure wash the grill to remove rust. Only the catch tray can be washed with water, per Atosa.

Natural Gas Setup and Gas Use

The ATCB-24 is set up for natural gas, with the supplied regulator set at 4" W.C. and a 3/4" NPT rear gas connection. The main burner orifices are #36 for natural gas in Atosa's charbroiler specifications. If your kitchen runs on propane, the radiant ATRC-24-LP comes ready for it.

Estimates use about 1,000 BTU per cubic foot of natural gas, 100,000 BTU per therm and about 21,500 BTU per pound of propane. Real use is lower when zones are turned down or off.

Gas conversion. Atosa's manual says the main burner orifices are installed at the factory and that switching gas means changing the orifices and the regulator setting, work that must be done only by authorized, licensed technicians. Do not attempt a conversion yourself.

Before You Order the ATCB-24

• Gas at the hookup: confirm you have natural gas at the cooking line. This listing is the natural gas model.
• Space: 24" wide x 27-3/5" deep, plus 6" at each side and the back. Measure about 36" of open, non-combustible counter or stand.
• Hood: the hood must cover the full 24" width with the overhang your code requires. Confirm with your code official before delivery.
• Gas supply: make sure your gas piping and meter can add 70,000 BTU/hr on top of the rest of the line. Ask your plumber or gas fitter.
• Connector: a commercial flexible gas connector sized for the load, with a quick disconnect and a restraining cable where code requires one.
• Support: a stand or chef base rated above 136.9 lb.
• Installer: book a licensed gas technician for install day.
• Delivery: the shipping weight is 168.2 lb. Plan who will receive and inspect the freight, and note any damage with the driver.

ATCB-24 Specifications

Installing the ATCB-24

From Atosa's charbroiler manual:

• Installation, adjustment and gas work by an authorized, licensed technician, to local code (or ANSI Z223.1/NFPA 54 where there is none). Otherwise the manufacturer may refuse warranty service.
• A level, solid, non-skid, non-combustible surface, away from customers and children.
• At least 6" clearance on both sides and the back and 4" underneath. With side clearance, plan about 36" of counter width.
• Install under an exhaust hood as local regulations require. Gas underfired broilers are classed as heavy-duty cooking appliances under the International Mechanical Code; confirm hood and fire suppression with your local code official.
• Screw in the 4 adjustable legs and level the unit. Lift it rather than dragging it.
• Spread the lava rock evenly on the bottom frame (pieces about 3 to 5 cm) after confirming the fire shields are in place.
• Leak-test every gas joint with soapy water or a detector, never a flame, and have the technician check working gas pressure.
• Disconnect the appliance shutoff valve during supply pressure tests above 1/2 psi (3.45 kPa).
• Keep fans and air conditioning from blowing on the flame. Do not use outdoors.

Stand or chef base. At 136.9 lb net, the ATCB-24 needs a non-combustible stand or a chef base rated for countertop cooking equipment, with capacity above the grill's weight. All Atosa charbroilers stand 15-1/5" tall, the same as Atosa's ATTG and ATMG countertop griddles, so a matched line sits level.

First-Day Setup

1. Level the grill and seat the catch tray.
2. Wipe it down with a mild detergent. No corrosive or abrasive cleaners.
3. With all knobs at "0", light the pilots. The first light can take a minute while air clears from the line.
4. Turn each knob counterclockwise to light the burners from the pilots.
5. Burn in: the first heat-up smokes as protective oil burns off. Atosa says it clears after about an hour at maximum. Run the hood and cook nothing during the burn-in.
6. Season the grates: oil them and run the grill open for 45 minutes, uncovered.
7. Preheat 15 to 20 minutes before each service.
8. After shutting off a main burner, wait more than 5 minutes before relighting it.

Daily Care

Turn off all valves and let the grill cool before cleaning. Do not hose down, immerse or pressure wash any part except the catch tray. Have the grill inspected by an authorized, licensed technician at least once a year.

Troubleshooting the ATCB-24

Adapted from Atosa's troubleshooting table. If anything goes wrong, stop using the grill and have a technician check it.

If you smell gas, shut off the main gas valve, put out all flames and call 911.

ATCB-24 FAQ

How many BTU is the ATCB-24?

70,000 BTU total from two 35,000 BTU burners on natural gas.

What size is the ATCB-24?

24" wide, 27-3/5" deep and 15-1/5" tall, with a 23-9/10" x 20-1/5" work area (about 483 sq in). It weighs 136.9 lb.

Does the ATCB-24 need a hood?

Yes. Atosa's manual requires installation under an exhaust hood per local regulations. Confirm hood and fire suppression requirements with your local code official.

How much clearance does it need?

At least 6" on both sides and the back and 4" underneath, on a non-combustible surface. Plan about 36" of counter width.

What gas connection does it need?

A 3/4" NPT rear connection; the supplied regulator is set at 4" W.C. for natural gas.

How do I season the grates?

Clean them, coat them with cooking oil and run the grill open for 45 minutes without covering the grates, per Atosa's manual.

Can I use it outdoors?

No. Atosa's manual says not to use the charbroiler outdoors.

What is the warranty?

1 year parts and labor, US only. Licensed installation and manufacturer parts are required to keep coverage.

Is the ATCB-24 good for carne asada?

Yes. Lava rock catches marinade and fat drippings and flares them back into the meat, which gives carne asada its char. Run one zone at full fire for the meat and the other lower for tortillas, onions and holding.

Does the lava rock need to be replaced?

Yes, eventually. Turn the rocks as grease builds up, and replace them when they are saturated, crumbled or causing constant flare-ups. Atosa calls for pieces about 3 to 5 cm across, spread evenly.

Compare every model in our commercial charbroiler guide. Questions? Call or text Sean at 206-419-5801.