How To Convert LP Gas Grill To Natural Gas Safely And Efficiently

Converting a liquid propane grill to run on a residential natural gas line requires changing the delivery pressure, swapping out orifice sizes to accommodate a lower BTU density per cubic foot, and installing specialized quick-disconnect plumbing. Executing this transition correctly eliminates the danger of fuel leaks, prevents unstable burner flames, and ensures your outdoor cooking equipment operates within manufacturer safety tolerances.

Pre-Operation & Equipment Checklist

Transitioning an outdoor barbecue from high-pressure liquid propane to low-pressure natural gas is not merely a matter of changing out the hose; it requires careful calculation of fuel supply pressures, volumetric flow rates, and precise orifice sizing. Liquid propane is stored at pressures near 100 to 200 PSI and burns hotter per cubic foot, whereas residential natural gas typically delivers a steady 4 to 7 inches of water column (W.C.), which equals roughly 0.25 to 0.28 PSI. Because natural gas delivers less energy per cubic foot, the burner orifices must be physically enlarged to allow a greater volume of gas to pass through to achieve optimal cooking temperatures.

• Essential Gear, Tools, and Materials:
  
  
  • Model-specific natural gas conversion kit (or individual natural gas orifices matched to your burner BTU output)
  • Approved natural gas supply hose with a 3/8-inch or 1/2-inch inner diameter
  • Quick-disconnect fitting and shut-off valve
  • Thread sealant rated for gas lines (yellow PTFE tape or pipe dope approved for natural gas)
  • Adjustable wrenches, nut drivers (typically 1/4-inch or 6mm), and a needle-nose pliers
  • Liquid leak detection solution (or a soap-and-water mixture in a spray bottle)
• Mandatory Prerequisite Knowledge and Standards:
  
  
  • Verify that your home natural gas supply line can handle the total maximum BTU load of your grill plus any other connected appliances.
  • Consult local municipal fuel gas codes and the National Fuel Gas Code (NFPA 54) to ensure compliant outdoor gas piping installations.
  • Never attempt to drill out existing LP orifices manually with household sewing needles or drill bits, as imprecise sizing can cause catastrophic flare-ups or carbon monoxide accumulation.
• Estimated Budget and Duration Benchmarks:
  
  
  • Financial investment: $50 to $150 depending on whether you purchase a brand-specific conversion kit or source individual fittings.
  • Time commitment: 1 to 2 hours of focused, methodical mechanical work.

Step-by-Step Conversion and Installation Workflow

Step 1: Disconnect the Liquid Propane Supply and Secure the Workspace

Begin by ensuring the grill is completely cool and turned off. Close the valve on your liquid propane tank tightly, disconnect the regulator assembly from the tank, and remove the tank entirely from the grill cart area. Move the propane tank at least 10 feet away from the work zone. Clean out any accumulated grease or ash from the bottom of the firebox to ensure clear access to the burner assemblies, valves, and manifold pipes.

Warning: Never work on gas supply lines while a pressurized tank or an active utility line is connected. Always shut off the upstream supply valve before removing any fittings.

Step 2: Remove the Grill Burners and Access the Manifold

Open the grill hood and remove the cooking grates, flame tamers, and any heat distribution plates. Locate the cotter pins, screws, or mounting clips that secure the rear of each main burner tube to the firebox floor. Slide the burners backward slightly and lift them out of the grill body, taking care not to bend the igniter electrodes. With the burners removed, you will have a clear line of sight to the control valves and the brass orifices threaded into the ends of the manifold pipe.

Step 3: Swap the Propane Orifices for Natural Gas Orifices

Using a nut driver or a properly sized open-end wrench, carefully unscrew the existing brass LP orifices from the valve stems or manifold. Inspect the threads on the manifold to ensure they are clean and free of debris. Take your replacement natural gas orifices—which feature a noticeably larger bore diameter to compensate for the lower pressure of natural gas—and wrap the male threads with two to three passes of yellow gas-rated PTFE tape. Thread the new natural gas orifices into the valve stems and snug them down firmly, but avoid over-tightening, which can strip the brass threads.

Pro-Tip: Keep the old LP orifices in a labeled plastic bag and tape them to the inside of your grill cabinet. If you ever move or sell the home, this allows a future owner to convert the grill back to liquid propane safely.

Step 4: Reinstall and Align the Burner Tubes

Place each burner tube back into its designated position in the firebox. Ensure that the open venturi ends of the burner tubes slide smoothly over the newly installed natural gas orifices. The orifices should project approximately 1/4 inch inside the burner venturi throat without touching the sides. Secure the rear of the burners with their original mounting hardware and reconnect or check the igniter electrodes to ensure reliable spark generation. Reinstall the flame tamers and cooking grates.

Step 5: Connect the Natural Gas Supply Hose and Quick-Disconnect

Locate your outdoor natural gas supply stub-out, which should feature an approved manual shut-off valve. Ensure this shut-off valve is in the "OFF" position. Attach the natural gas supply hose to the grill manifold inlet, typically using a flare fitting that does not require thread sealant, though threaded pipe connections require yellow gas tape or pipe dope. Connect the other end of the hose to the quick-disconnect fitting on your household gas supply line. Push back the sleeve of the quick-disconnect socket to firmly click the plug into place.

Step 6: Pressure and Leak Test the Entire System

Before attempting to ignite the grill, you must verify that every single connection is completely airtight. Turn on the main natural gas supply valve at the house wall stub. Generously apply your liquid leak detection solution (soapy water) to every joint you touched: the orifices, the manifold connections, the supply hose fittings, and the quick-disconnect coupling. Watch closely for the formation of expanding soap bubbles. If bubbles appear, shut off the gas supply immediately, disassemble the leaking joint, reapply thread sealant, and tighten the fitting before retesting.

Technical Specifications and Component Comparison

Common Site Failures and Field Fixes

• Root Cause: Yellow, lazy, and soot-producing burner flames combined with a distinct gas odor.
  
  
  • Actionable Fix: This indicates incomplete combustion, usually caused by improper air shutter adjustment on the burner venturis or an incorrect orifice size. Open the air shutters slightly to introduce more oxygen, and verify that you installed natural gas orifices rather than accidentally retaining the smaller LP components.
• Root Cause: The grill fails to reach high temperatures (struggling to get past 400 degrees Fahrenheit).
  
  
  • Actionable Fix: Undersized gas supply piping or an inline pressure regulator restriction is starving the burners. Ensure your natural gas supply line features at least a 1/2-inch inner diameter pipe from the meter, and verify that any excess flow safety valves are not tripping due to sudden opening surges.
• Root Cause: Soap bubbles expand rapidly at a threaded manifold joint during the leak test.
  
  
  • Actionable Fix: The fitting was under-tightened or lacked adequate thread sealant. Turn off the main gas supply, disassemble the leaking connection, clean off old residue, apply fresh yellow gas-rated PTFE tape, and retighten securely.

Frequently Asked Questions

Can I convert any gas grill from propane to natural gas?

Most standard name-brand gas grills can be converted using manufacturer-approved conversion kits or generic components. However, you must check the owner's manual or contact the manufacturer to verify that conversion parts exist for your specific model, as some proprietary valve assemblies cannot be safely modified.

Why do I need to change the orifices if both fuels are gas?

Liquid propane and natural gas possess vastly different energy densities and delivery pressures. Because natural gas delivers fewer BTUs per cubic foot and runs at a much lower pressure, the burner orifices must be physically larger to allow a greater volume of gas to pass through and produce equivalent cooking heat.

Can I use a standard garden hose or propane hose for natural gas?

No. You must use a certified natural gas supply hose constructed from materials specifically tested to withstand natural gas composition without degrading. Standard propane hoses and generic rubber tubing can crack, deteriorate, or leak when exposed to natural gas over time.

Will converting my grill to natural gas void the manufacturer warranty?

Using non-approved third-party parts to modify a grill often voids the manufacturer warranty. To protect your warranty coverage, purchase official conversion kits directly from the grill manufacturer and have the installation verified by a licensed gas technician where local codes require it.

What should I do with my old propane tanks after converting?

Empty propane tanks can be traded in at local exchange kiosks, repurposed for portable fire pits, or recycled at designated hazardous waste and metal recycling facilities. Never discard a pressurized or partially filled propane tank in standard residential trash.

Upgrade your outdoor cooking setup today with a certified natural gas conversion kit and enjoy uninterrupted, tank-free grilling for all your backyard gatherings.