Gas Range Propane Conversion: Expert Guide for Safe, Efficient Performance

A gas range propane conversion takes a commercial range that was built and shipped configured for natural gas and re-jets, re-regulates, and re-seals it to run safely on liquid propane (LP). The conversion is a real piece of work, not a switch flip: every burner orifice gets swapped for a smaller LP orifice, the pressure regulator is flipped or replaced for LP service, the manifold pressure is reset from 5 inches water column to 10 inches water column, and the entire system is leak-tested and flame-checked before the range goes back into service. This guide walks through when conversion makes sense, the procedure step by step, code and safety requirements, what it costs, and when you should buy a factory-LP range instead of converting an existing NG unit.

The Atosa AGR series is built for field conversion: every NG-configured AGR ships from the factory with an LP conversion kit packed inside the oven cavity, including LP orifices for every burner, the LP regulator spring or replacement regulator, and the LP rating plate. Converting is straightforward when done by a qualified gas technician. Doing it wrong creates yellow-flame burners, soot deposits, carbon monoxide risk, and a guaranteed inspection failure.

When to Convert a Gas Range from Natural Gas to Propane

Conversion makes sense in specific situations. It is the wrong answer in others.

Convert when:

• The site has propane service only. Rural restaurants, food trucks transitioning to a permanent location, mountain or coastal sites without utility natural gas service, and most non-urban catering kitchens run propane because no NG line exists at the property.
• You bought a used or surplus NG range at a discount and the new site is LP. The conversion cost (parts plus labor) is typically $150 to $400 versus a $1,500 to $3,000 difference for buying new LP, so conversion saves money on used equipment.
• You are relocating an existing range from an NG site to an LP site. The range is paid for and known good; converting it is faster and cheaper than buying replacement.
• The AGR ships NG by default and your site is LP. Atosa expects this and includes the LP kit in the oven cavity at no extra cost. If you ordered the wrong fuel type, conversion is the fix.

Do not convert when:

• The range was not designed for field conversion. Some imports and most residential ranges cannot be safely converted. The Atosa AGR series and most commercial brands are designed for conversion. Confirm before you start by checking the rating plate and operating instructions for the LP rating and orifice sizes.
• You are not a licensed gas technician. Conversion is not a homeowner job, not a manager job, and not a maintenance porter job. It requires a licensed plumber or gas fitter, leak testing equipment, and the right wrenches and torque specs. A botched conversion is a fire and carbon monoxide hazard.
• The site has NG service available. If utility natural gas is at the property line, run NG. Operating cost on NG is roughly half of LP, and conversion adds a step you do not need.
• You are buying new and the supplier carries the LP SKU. If you are ordering a new range, order the LP part number directly. The factory-LP unit ships pre-configured and ready to install. No conversion labor, no risk of installer error.

What Changes in a Natural Gas to Propane Conversion

Natural gas and propane are different fuels with different combustion characteristics. The range hardware has to match the fuel.

• Burner orifices. Natural gas orifices are larger (more open) because NG has lower energy density (about 1,030 BTU per cubic foot) and lower supply pressure (5 inches water column at the manifold). Propane orifices are smaller because LP has higher energy density (about 2,500 BTU per cubic foot) and higher manifold pressure (10 inches water column). A natural gas orifice running on propane will produce an oversize flame, soot, and carbon monoxide. Every burner on the range gets a new orifice during conversion. The Atosa AGR series uses these specific orifice part numbers:

• Open burner (hot plate): NG38 for natural gas, LP51 for propane, both rated 32,000 BTU.
• Griddle burner: NG42 for natural gas, LP52 for propane, both rated 27,000 BTU.
• Oven burner, U-shape: LP54 for propane, rated 21,000 BTU.
• Oven burner, I-shape: LP53 for propane, rated 24,000 BTU.

The U-shape and I-shape oven burner distinction matters when ordering parts: an I-shape orifice in a U-shape burner runs lean and causes long oven preheat times. Verify the burner geometry before ordering replacement orifices, and use the matching part number.

• Pilot orifices. The standing pilot orifices are sized for the fuel just like the main burner orifices. The LP conversion kit includes pilot orifices that are swapped at the same time.
• Pressure regulator. The Atosa AGR regulator is a convertible design: a spring or cap is flipped from the NAT position to the LP position to change the output pressure setpoint from 5 inches water column (NG) to 10 inches water column (LP). On some other commercial ranges, the regulator is replaced entirely. The conversion kit includes whatever the manufacturer specifies.
• Manifold pressure. After the regulator is flipped, the manifold pressure is verified with a manometer at the test port. NG target is 5 inches water column. LP target is 10 inches water column.
• Rating plate. The factory rating plate shows the original NG configuration. After conversion, the LP rating plate (included in the kit) is applied next to or over the NG plate, identifying the range as converted to LP and showing the new BTU and pressure values. The inspector will check for this plate.
• Air shutter adjustment. After ignition, each burner air shutter is adjusted for a steady blue flame with sharp inner cone and slight yellow tips. LP runs leaner than NG, so the shutter settings change. If the flame lifts off the burner ports, the shutter is open too far and is closed incrementally.

Step-by-Step Natural Gas to Propane Conversion Procedure

The full procedure below is a summary. Always follow the manufacturer operating instructions packed with the range, as exact orifice sizes, regulator design, and torque specs vary by model.

Step 1: Shut Off and Disconnect Gas

• Close the building shutoff valve upstream of the range.
• Disconnect the flex hose from the range intake.
• Disconnect the electrical cord (the AGR oven thermostat and pilot ignition module run on 120V).
• Pull the range out from the wall for full access to the back panel and manifold.

Step 2: Remove the Burner Caps and Grates

• Lift off all grates, burner caps, and burner heads. Set aside on a clean surface.
• Photograph the orientation of each burner head if any are different sizes (most AGR models use uniform 32,000 BTU burners, but combo units have smaller pilot burners).

Step 3: Replace the Burner Orifices

• Using a 7/16" or 1/2" deep socket (a deep socket prevents rounding the brass hex head), unthread each main burner orifice from the manifold gas tap.
• Install the LP orifice from the conversion kit at each burner location. Hot plates take LP51, griddle burners take LP52, oven burners take LP53 (I-shape) or LP54 (U-shape). Torque to manufacturer spec (finger-tight plus a quarter turn with the wrench).
• Use only yellow PTFE thread seal tape rated for gas service on threaded joints. Standard white PTFE tape is too thin and can be degraded by propane, leading to micro-leaks. Yellow tape is the inspector standard.
• Verify the orifice stamp matches the LP rating in the operating instructions.

Step 4: Replace the Pilot Orifices

• Remove each cooktop pilot orifice (small fitting on the pilot tube).
• Install the LP pilot orifice from the conversion kit.
• For combination cooktop and oven models, the oven pilot orifice is also replaced. Access is through the bottom of the oven cavity (the oven floor pan lifts out).

Step 5: Convert or Replace the Regulator

• On the Atosa AGR series, the regulator is a convertible design. Remove the screw cap, flip the inner spring or pin from NAT to LP per the diagram on the operating instructions, and reinstall the cap.
• On other commercial brands, the regulator is replaced entirely with the LP regulator from the conversion kit.
• Verify the regulator orientation arrow points downstream toward the manifold.

Step 6: Reconnect to LP Supply

• Connect the flex hose to the LP supply shutoff valve. Most LP installations use a 3/4 inch NPT flex hose just like NG.
• The LP tank or building distribution must be sized for the connected load. A standard 100-pound LP tank supplies roughly 90,000 BTU per hour continuously; an AGR-6B at 219,000 BTU total connected load needs a 250-pound tank or multiple 100-pound tanks manifolded together.
• Connect the electrical cord.

Step 7: Leak Test

• Open the LP supply valve slowly.
• Apply soap solution at every joint: the supply valve, the flex hose at the supply end, the flex hose at the range end, the regulator inlet and outlet, the manifold connections at every burner, and the orifice threads. No bubbles allowed; any bubbling means the joint is reworked.
• Run a manometer test at the manifold test port. Connect a digital manometer, fire at least 50 percent of the burners plus the oven at maximum input, and verify the pressure stabilizes between 10 and 11 inches water column. If pressure drops below 10 inches water column under load, the LP supply line or tank regulator is undersized for the connected BTU.

Step 8: Light and Adjust Each Burner

• Light each cooktop pilot per the operating instructions. The LP pilot flame should burn at 1/4 to 1/2 inch tall. A pilot too high causes soot buildup on the thermocouple and premature safety valve failure.
• Light each main burner. Verify a steady blue flame with sharp inner cone and no yellow tips.
• Adjust each burner air shutter for clean combustion. LP runs leaner than NG, so the air shutter typically gets closed slightly compared to the NG setting.
• Light the oven pilot (hold the safety valve button down 10 to 15 seconds while igniting). Verify the oven pilot stays lit when the button is released.
• Bring the oven to 350 degrees Fahrenheit from cold. Verify a 12 to 15 minute heat-up time and that the oven thermostat cycles correctly.

Step 9: Apply the LP Rating Plate

• Affix the LP rating plate from the conversion kit next to or over the factory NG rating plate. The plate identifies the range as converted to LP and shows the new BTU and manifold pressure values.
• Document the conversion in the range maintenance log (date, technician name, license number).

Step 10: Final Inspection

• In most jurisdictions, a building department or gas inspector will verify the conversion before the range is approved for commercial service. The inspector checks the LP rating plate, leak-tests the joints, and verifies manifold pressure.
• Once approved, return the range to its final position with the back accessible, install the restraint cable, and place the range back into service.

Propane Conversion Code and Safety Requirements

Propane installations are governed by the same family of codes as natural gas, with propane-specific additions for tank storage, venting, and leak detection. Inspectors look for the following on a converted range install:

• CSA B149.2 Propane Storage and Handling Code (Canada and CSA-adopting jurisdictions). Covers tank placement, distance from buildings, venting, and pressure testing.
• NFPA 58 Liquefied Petroleum Gas Code (United States). Covers LP storage, handling, transport, and use. Most US jurisdictions reference NFPA 58 directly or through state propane regulations.
• ANSI Z83.11-2016 commercial gas food service equipment standard (applies to both NG and LP commercial ranges).
• ETL or UL listing on the range as a commercial gas appliance.
• NSF/ANSI 4 sanitation listing for foodservice equipment.
• Local fire code on LP tank storage, distance from the building, fencing or barrier requirements, and signage. Many municipalities require an above-ground LP tank to be at least 10 feet from any building opening and 5 feet from any property line.
• Hood and fire suppression coordination is identical to NG: a Type 1 hood with a wet-chemical fire suppression system is required above the range in all commercial installations.

Propane is heavier than air. If a leak occurs, LP gas accumulates at floor level rather than dissipating upward like natural gas. This is why LP-fired equipment is never installed below grade in most jurisdictions (no basement installations) and why LP detection sensors mount low on the wall rather than high.

What Propane Conversion Costs

The conversion itself is inexpensive. The variable is labor.

• LP conversion kit: $0 if the kit shipped with the range (the AGR series ships with the kit in the oven cavity at no extra charge). $50 to $200 if ordered separately for a range that did not ship with one.
• Licensed plumber or gas technician labor: $150 to $400 for a straightforward conversion on a single range. The work takes 1.5 to 3 hours depending on the range size and access.
• Building department inspection fee: $50 to $200 depending on jurisdiction.
• LP tank installation (if not already on site): $500 to $2,000 for a 250 to 500 pound above-ground tank plus regulator, gauge, and supply line. Tank rental from a propane supplier is typically $100 to $300 per year.

Total conversion cost for the range only (kit, labor, inspection) is typically $200 to $600. Total install including tank infrastructure for a new LP site is $2,000 to $5,000.

Compare against buying new LP versus new NG: the LP and NG part numbers of an Atosa AGR are priced identically. There is no premium for LP at the manufacturer. The reason to convert (instead of swap to factory-LP) is usually that you already own the NG range or you got the NG unit on a discount.

Atosa AGR Conversion-Ready Models

Every Atosa AGR series range ships with the LP conversion kit packed in the oven cavity, and every model can be field-converted between NG and LP using the included kit. Choose the AGR-LP factory-configured part number when buying new for an LP site, or convert an AGR-NG unit when relocating or repurposing.

• Atosa AGR-4B (24-inch, 4-burner, 1 standard oven): 152,000 BTU total. AGR-4B-NG factory natural gas or AGR-4B-LP factory propane.
• Atosa AGR-6B (36-inch, 6-burner, 1 standard oven): 219,000 BTU total. AGR-6B-NG factory natural gas or AGR-6B-LP factory propane.
• Atosa AGR-8B (48-inch, 8-burner, 2 standard ovens): 310,000 BTU total. AGR-8B-NG factory natural gas or AGR-8B-LP factory propane.
• Atosa AGR-10B (60-inch, 10-burner, 2 standard ovens): 374,000 BTU total. AGR-10B-NG factory natural gas or AGR-10B-LP factory propane.

Browse the full lineup of propane gas ranges or natural gas ranges, or see the complete commercial range collection.

When Conversion is the Wrong Move: Buy Factory-LP Instead

Conversion is the right call for used equipment and existing inventory. For new purchases, buy the factory-LP part number every time. The reasons:

• No labor charge. Factory-LP ships ready to install. No technician labor for field conversion.
• No risk of installer error. Factory-LP is configured and pressure-tested at the factory. Conversion adds a step where mistakes happen.
• No rating plate confusion. Factory-LP shows the original LP rating plate from the factory. Inspectors find this cleaner than a conversion plate over the NG plate.
• Same price. Atosa prices the AGR-LP and AGR-NG part numbers identically. There is no cost savings to buying NG and converting.

The only reason to buy NG and convert is if the NG unit is what your distributor has in stock and the wait for the LP SKU is too long. Even then, the conversion is a several-hundred-dollar add-on. For a site that will be LP from day one, order LP.

Operating Cost: Propane vs Natural Gas

Propane operating cost is roughly 2 to 2.5 times higher than natural gas per equivalent BTU delivered. Sample annual costs for an AGR-6B (219,000 BTU total) at medium-duty operation (10 hours per day, 30 percent average duty cycle, 365 days per year):

• Natural gas: 240 MMBTU per year at $11 per MMBTU utility rate = $2,640 per year.
• Propane: 240 MMBTU per year at $26 per MMBTU LP rate (roughly $2.40 per gallon at 91,500 BTU per gallon) = $6,240 per year.

The annual operating cost difference is $3,600 in favor of natural gas, single range only. For a full cookline with range, griddle, and fryer, the gap widens to $8,000 to $15,000 per year. If natural gas is available at your site, run NG. Propane is the right answer only when NG service is unavailable or impractical (food truck, rural site, mobile catering).

For the full natural gas economics breakdown, see the natural gas ranges guide. For the full operating cost analysis across range, refrigeration, and the rest of the cookline, see commercial refrigerator operating cost.

Orifice Cleaning and Maintenance

Brass orifices are precision-drilled to a specific diameter. The hole size determines BTU output, and the manufacturer tolerance is tight. Never clean an orifice with a steel wire, drill bit, or any rigid metal probe. Even light pressure from a metal probe can enlarge the precision-drilled hole, raising BTU output above the safety rating and producing oversize flames that overheat the burner head and surrounding components.

To clean a clogged orifice:

• Remove the orifice from the manifold using the deep socket.
• Blow out debris with compressed air, working from the outlet side back through to the inlet.
• For stubborn carbon deposits, use a soft nylon brush. Never steel wool, never wire.
• If the orifice cannot be cleaned without damage, replace it. New brass orifices from the manufacturer are inexpensive and guaranteed to match the original specification.

Annual manometer verification is recommended on any LP range. Regulator springs lose tension over time, and a manifold pressure that drops below 10 inches water column produces undersize flames and long cook times. A two-minute manometer check at the test port catches this before it affects production.

Conversion Mistakes That Fail Inspection

Building inspectors see the same conversion failures over and over. Avoid these:

• NG orifices left in place on one or more burners. Yellow flame and soot are the giveaway. The inspector lights every burner.
• Regulator plunger not flipped from NAT to LP. The convertible regulator on the AGR has a plastic plunger inside the screw cap; flipping it inverts the spring loading to LP service. If the technician forgets this step, the manometer reads 5 inches water column instead of 10. The inspector tests this.
• LP rating plate missing. Without the conversion plate, the inspector has no documentation that the range was professionally converted. Fails inspection.
• Leak at a fitting reworked during conversion. White PTFE tape used on a propane fitting is a common cause. Use yellow PTFE tape rated for gas. The inspector soap-tests every joint.
• Conversion performed by an unlicensed person. Most jurisdictions require a licensed plumber or gas fitter to perform the work. The inspector will ask for the license number on the maintenance log.
• Hood and fire suppression coordination missing. An LP range still requires a Type 1 hood with wet-chemical fire suppression in any commercial installation. Some operators forget this for converted ranges in catering or food truck commissary settings.
• LP tank improperly placed. Too close to the building, no barrier, no signage, undersized for connected load. The fire marshal checks this independently.

Reversing a Propane Conversion Back to Natural Gas

Conversion is reversible. If a range is moved from an LP site back to an NG site, the same procedure runs in reverse: LP orifices come out, NG orifices go in, the regulator flips back from LP to NAT, the manifold pressure resets to 5 inches water column, and the NG rating plate is restored.

Keep the original NG orifices when you do an NG-to-LP conversion. Tape them in a labeled bag inside the range or on top of the oven cavity. If the range is ever resold or relocated, the next owner needs those orifices for reverse conversion.

Field Conversion vs Factory Conversion

Field conversion is what we have described so far: a licensed technician changes the orifices, regulator, and rating plate at the install site. Factory conversion means the range is configured for the target fuel at the manufacturer before shipping. Factory is preferred when buying new because there is no labor and no risk of installer error.

If you are placing a new order with a distributor, ask explicitly for the LP part number, not "the LP version" or "the propane model." The part number on the box and rating plate must show the LP suffix (AGR-4B-LP, not AGR-4B-NG with a conversion kit). Confirm at receiving before the range goes into the install.

Frequently Asked Questions

Can I convert a natural gas range to propane myself? No. Conversion requires a licensed plumber or gas fitter in nearly every jurisdiction. The work involves orifice swaps at every burner, regulator changes, leak testing with a manometer, and a final inspection. A botched conversion is a fire and carbon monoxide hazard. Save the labor cost for a professional.

How long does a propane conversion take? 1.5 to 3 hours for a single range, plus inspection time. The bulk of the labor is removing and reinstalling burners, replacing each orifice, and leak testing. Larger ranges (AGR-8B, AGR-10B) take longer because there are more orifices to swap.

Does converting a range to propane void the warranty? No, as long as the conversion is performed by a licensed technician using the manufacturer-supplied conversion kit and the conversion is documented in the maintenance log. Atosa explicitly supports field conversion on the AGR series. Using non-OEM orifices or skipping the rating plate update can void the warranty.

Can a propane range be converted to natural gas? Yes. The reverse procedure swaps LP orifices out for NG orifices, flips the regulator from LP back to NAT, and resets manifold pressure to 5 inches water column. Keep the original NG conversion kit and rating plate.

What size propane tank do I need for a commercial range? Depends on connected load. A 100-pound LP tank supplies roughly 90,000 BTU per hour continuously in mild weather (less in cold weather due to vaporization rate limits). An AGR-4B at 152,000 BTU needs a 250-pound tank or two 100-pound tanks manifolded. An AGR-6B at 219,000 BTU needs a 250 to 500-pound tank. Larger ranges and full cooklines need 500 to 1,000-pound tanks or a buried bulk tank.

Why is propane more expensive than natural gas? Propane is a byproduct of natural gas processing and oil refining, distributed by truck and stored in tanks rather than piped. The logistics and storage costs raise the delivered price. Propane also has a higher energy density per cubic foot than natural gas, but the cost per delivered BTU is still roughly 2 to 2.5 times higher than utility natural gas.

Can I run a commercial range on a residential propane tank? Almost never. Residential LP tanks (typically 100 to 250 pounds) cannot sustain the BTU demand of a commercial range running multiple burners at full output. The tank will frost over from vaporization cooling and the regulator will lock out. Commercial ranges need commercial-grade LP supply, sized to total connected load.

Is the conversion kit included with every Atosa AGR? Yes. Every Atosa AGR ships with the LP conversion kit packed inside the oven cavity, including LP orifices, the LP regulator spring or replacement regulator, and the LP rating plate. The kit is included at no extra charge whether you buy the NG or LP part number.

What is the manifold pressure target for propane? 10 inches water column at the manifold test port, verified with a manometer at commissioning. Natural gas runs at 5 inches water column. The pressure regulator on the AGR series sets this automatically once the NAT/LP setting is correct.

Do I need a special hood for a propane range? No. Type 1 hood and wet-chemical fire suppression requirements are identical for NG and LP commercial ranges. The hood is sized to BTU connected load, not fuel type.

Can a propane range be installed in a basement? Generally no. Propane is heavier than air and accumulates at floor level if it leaks. Most jurisdictions prohibit LP-fired equipment below grade for this reason. Natural gas can sometimes be installed in a basement with proper ventilation. Always check local code.