How To Convert LP To Natural Gas Grill: The Definitive Conversion Guide
Converting a liquid propane grill to natural gas requires modifying the fuel delivery system to handle lower pressure and higher volumetric flow rates by replacing or re-machining the burner orifices and swapping out the regulator hose assembly. Because natural gas operates at roughly half the pressure of propane (7 inches of water column versus 11 inches) and delivers less energy per cubic foot, failing to use the correct orifice sizing will result in erratic flames, dangerously low heat outputs, or uncombusted gas accumulation.
Pre-Operation & Equipment Checklist
Transitioning a grill from a high-pressure liquid propane tank to a low-pressure residential natural gas supply line requires precise tools, strict adherence to safety standards, and exact hardware matching. Propane gas is heavier than air and pools dangerously at ground level, whereas natural gas is lighter than air and dissipates upward; however, both gases require total elimination of leaks to prevent fire or explosion hazards.
- Essential Gear, Tools, and Materials:
- Gas-rated thread sealant (pipe dope approved for natural gas/propane) or yellow gas-rated PTFE plumber's tape.
- Nut drivers, open-end wrench set, and an adjustable wrench.
- A certified natural gas conversion kit specific to your grill brand and model (including new natural gas orifices, a specialized control valve or regulator adjustment mechanism, and a quick-disconnect natural gas hose).
- Electronic leak detector solution or a mixture of dish soap and water in a spray bottle.
- Drill bit set (only if manually re-drilling orifices per manufacturer engineering charts, though direct replacement is heavily preferred).
- Mandatory Prerequisite Knowledge and Standards:
- Verify that your home natural gas supply line and meter can support the total BTU load of your home appliances plus the grill. A standard residential meter supplies approximately 250,000 to 400,000 BTUs per hour.
- Ensure all work complies with the National Fuel Gas Code (ANSI Z223.1/NFPA 54) or local municipal plumbing and gas codes.
- Budget and Duration Benchmarks:
- Estimated cost ranges from $50 to $150 for certified OEM conversion kits and quick-disconnect fittings, or up to $300 if hiring a certified gas technician.
- Time commitment is approximately 1 to 2 hours for an intermediate DIYer.
Step-by-Step Grill Conversion Execution
Step 1: Disconnect and Secure the Existing Propane System
Turn off the supply valve on your propane tank, disconnect the regulator hose from the tank, and remove the tank completely from the grill cart. Pull the grill away from any structures to ensure a clear, well-ventilated workspace. Remove the cooking grates, flavorizer bars, and heat tents to gain unhindered access to the main burner tubes, manifolds, and control valves.
Warning: Never attempt any gas conversion work while connected to a pressurized propane tank or an active natural gas line. Ensure all control knobs are in the absolute "Off" position.
Step 2: Access the Burner Manifold and Orifices
Locate the control panel and remove the retaining screws holding it in place. Carefully detach any electronic ignition wires connected to the igniter module or electrodes. Slide the control panel off to expose the brass brass orifices threaded into the ends of the gas valves, where they inject fuel directly into the venturi tubes of each burner. Take note of how the burners are secured to the firebox (usually via cotter pins, clips, or a single mounting screw) and remove them if necessary to inspect the interior of the throat.
Step 3: Replace Propane Orifices with Natural Gas Equivalents
Unscrew the existing propane orifices from the manifold valve stems using an appropriate wrench or socket. Because propane requires a smaller hole due to its higher pressure and energy density, natural gas orifices feature significantly larger bore diameters. Thread the correct natural gas orifices into the valve tips, applying a minimal amount of gas-rated pipe dope or sealant to the male threads if specified by the manufacturer.
Pro-Tip: Do not over-torque brass orifices during installation. Snug them down firmly to create a seal, but excessive force can shear the delicate brass threads inside the aluminum manifold valve.
Step 4: Swap the Regulator and Supply Hose Assembly
Disconnect the existing high-pressure propane regulator hose from the manifold inlet. Attach the low-pressure natural gas hose assembly, which typically terminates in a quick-disconnect fitting, directly to the grill manifold inlet or pressure regulator inlet depending on your specific model architecture. Many conversion kits require removing the propane regulator entirely because the home natural gas supply is already regulated at the house meter.
Step 5: Connect to the Natural Gas Source and Perform Leak Testing
Plug the grill's quick-disconnect hose into your dedicated backyard natural gas supply valve. Turn on the main natural gas supply valve at the wall or post. Generously brush or spray your soapy water solution over every single connection point, including the newly installed orifices, manifold fittings, hose attachments, and the quick-disconnect joint.
Warning: Look closely for expanding bubbles or foam. If bubbles form or you smell the distinct odor of mercaptan (rotten egg gas additive), immediately shut off the gas supply, tighten the leaking fitting, and re-test. Never use an open flame to check for gas leaks.
Natural Gas To Propane Converter GRLP3 LP Gas Conversion Kit For ...
Fuel Delivery Specifications and Conversions
| Parameter | Liquid Propane (LP) | Natural Gas (NG) |
|---|---|---|
| Supply Pressure | 11.0 inches of Water Column (approx. 0.4 psi) | 7.0 inches of Water Column (approx. 0.25 psi) |
| Energy Density | ~2,500 BTUs per cubic foot | ~1,000 BTUs per cubic foot |
| Orifice Bore Size | Smaller diameter (higher restriction required) | Larger diameter (lower restriction required) |
| Vapor Density | Heavier than air (settles in low spots) | Lighter than air (dissipates upward) |
| Storage Method | Portable pressurized steel/composite tanks | Underground or exterior rigid utility supply lines |
Common Conversion Failures and Field Fixes
- Low Flame Height and Inadequate Heat Output:
- Root Cause: The conversion was performed using original propane orifices, or dirt/spider webs are obstructing the larger natural gas orifices.
- Actionable Fix: Verify that every single propane orifice was replaced with the corresponding natural gas part number. Clear any debris from the burner venturis using a soft brush or pipe cleaner.
- Yellow, Sooty Flames That Leave Black Residue on Cookware:
- Root Cause: Incorrect air shutter adjustment on the burner tubes, preventing the proper mixing of primary air with the natural gas stream.
- Actionable Fix: Locate the air shutter adjustment screws near the base of the burner tubes where they slide over the orifices. Open the shutters slightly to allow more oxygen to mix with the gas until the flame burns a clean, steady blue with minimal yellow tips.
- Gas Odor Present Without Flames Lit:
- Root Cause: Improperly seated quick-disconnect fitting or unsealed threads on the manifold conversion joints.
- Actionable Fix: Shut off the main gas supply immediately. Re-apply yellow gas tape or pipe dope to threaded connections, ensure the quick-disconnect collar clicks fully into the locked position, and re-run the soap bubble test.
Frequently Asked Questions
Can I drill out my old propane orifices to convert to natural gas?
Manually drilling out propane orifices to natural gas specifications is strongly discouraged. Precision drill bits can easily tear, flare, or misalign the brass hole, causing uneven gas flow, uncontrollable flames, or gas leaks. Always purchase a certified, OEM-matched conversion kit for your specific grill model.
Will converting my grill to natural gas lower its maximum BTU output?
Most converted grills experience a minor reduction in total BTU output (typically 10% to 15%) because natural gas has a lower energy density per cubic foot than propane. However, this difference is rarely noticeable during actual cooking operations, and you will never run out of fuel mid-barbecue again.
Can I convert a natural gas grill back to liquid propane?
Yes, converting a natural gas grill back to liquid propane is entirely possible by reversing the process. You must replace all natural gas orifices with the original propane-sized orifices, swap out the low-pressure hose for a high-pressure propane regulator assembly, and reconnect a standard propane tank.
Do I need a professional plumber to install a natural gas line for my grill?
If you already have a pre-existing, stubbed-out natural gas supply line with a shut-off valve on your patio or deck, you can typically complete the appliance connection yourself. However, running a new gas supply line from your home meter to the patio requires a licensed plumber or gas fitter to ensure compliance with local building codes.
Upgrade Your Outdoor Cooking Experience Today
Transitioning your cooking setup to a permanent utility line eliminates the hassle of empty propane tanks while providing uninterrupted fuel for endless grilling sessions. Secure your certified conversion hardware today and enjoy the reliable, maintenance-free performance of natural gas cooking.
