If you’ve recently switched to LPG (Liquefied Petroleum Gas) or moved to a property where it’s the primary fuel source, that beautiful sealed burner gas cooktop in your kitchen suddenly presents a challenge. Natural gas and LPG operate at different pressures and require different gas orifice sizes, meaning your cooktop won’t function safely or efficiently without modification. The good news? With the right knowledge, tools, and a methodical approach, converting a sealed burner gas cooktop to LPG is a straightforward DIY project that experienced homeowners can complete in about 20 minutes of actual hands-on work.
Before we dive into the nuts and bolts, let’s be crystal clear about that timeframe: the “20-minute conversion” assumes you’ve already obtained the correct conversion kit, understand your cooktop’s BTU ratings, and have prepared your workspace. For first-timers, the entire process—including research, preparation, and safety testing—will realistically take 1-2 hours. This guide walks you through every step with the technical depth and safety emphasis you’d expect from a master technician, ensuring your conversion is both code-compliant and kitchen-ready.
Understanding the LPG Conversion Process
Why Gas Cooktops Need Conversion
Natural gas and LPG might seem interchangeable—they’re both gases that burn to create heat—but their physical properties differ dramatically. Natural gas (methane) enters your home at a lower pressure, typically around 7 inches of water column (WC), while LPG (propane or butane) operates at a higher pressure of about 11 inches WC. This pressure difference isn’t just a technical detail; it’s the reason your cooktop’s burner orifices must be changed.
The orifices are precision-drilled holes that control gas flow to each burner. A natural gas orifice is larger to accommodate lower pressure and different energy content. If you connect an unconverted cooktop to LPG, the higher pressure forces significantly more fuel through those oversized holes, creating dangerously large flames, incomplete combustion, soot production, and potential carbon monoxide hazards. The conversion process essentially “tunes” your cooktop to speak LPG’s language fluently.
Sealed vs. Open Burners: What Makes the Difference
Sealed burner cooktops feature burners that are integrated into the cooktop surface with a sealed base, preventing spills from dripping down into the internal components. This design is sleek, easier to clean, and increasingly popular in modern kitchens. However, that sealed design means accessing the orifices requires a slightly different approach than traditional open-burner models.
The conversion principle remains identical—swap orifices and adjust the regulator—but sealed burners often require removing the entire cooktop from the countertop or accessing components from below. The sealed design also means you’ll need to be extra diligent about leak testing, as gas could potentially accumulate beneath the surface if connections aren’t perfectly sealed. Understanding this distinction is crucial before you start disassembling your appliance.
Safety First: Essential Precautions Before You Begin
Tools and Materials You’ll Need
Gathering the right equipment beforehand is non-negotiable for both safety and efficiency. You’ll need a comprehensive LPG conversion kit specific to your cooktop model (these typically include orifices, regulator spring, and adjustment instructions), a 3/8-inch and 7/16-inch wrench set, a small adjustable wrench, Teflon tape rated for gas lines, a leak detection solution or electronic gas detector, a screwdriver set, and a digital caliper for verifying orifice sizes.
Don’t forget personal protective equipment: safety glasses, work gloves, and a fire extinguisher rated for gas fires should be within arm’s reach. Keep a flashlight handy for inspecting dark corners underneath the cooktop, and have your smartphone ready to photograph the original configuration before disassembly. These photos become invaluable if you need to troubleshoot or revert the changes.
When to Call a Professional Instead
While this guide empowers competent DIYers, certain situations demand professional intervention. If your cooktop is hard-piped without a flexible gas connector, if you lack the proper tools, if you’re uncomfortable working with gas at all, or if local codes require certified installation—stop and call a licensed gas fitter. The same applies if you discover damaged gas lines, corroded fittings, or if your cooktop is more than 15 years old and parts are scarce.
Professional conversion typically costs between $150-$300, a worthwhile investment compared to the risks of improper installation. Many jurisdictions require a permit and inspection for gas appliance modifications, and DIY work done incorrectly can void your homeowner’s insurance if a problem occurs. Know your limits; gas work is not the place to learn by trial and error.
The 20-Minute Conversion Reality Check
Let’s set realistic expectations. The actual mechanical work—removing old orifices, installing new ones, and adjusting the regulator—can indeed take as little as 20 minutes for someone who’s done it before. However, that doesn’t account for the 30-45 minutes of leak testing that must follow, nor the time spent double-checking orifice sizes against manufacturer specifications.
First-timers should budget 90 minutes to 2 hours total. This includes 15 minutes for safety preparation, 20-30 minutes for disassembly and orifice replacement, 10 minutes for regulator adjustment, and a mandatory 30-45 minutes for comprehensive leak testing and burner flame optimization. Rushing any step, especially leak testing, transforms a simple conversion into a potential household hazard. The 20-minute promise is achievable, but only as part of a larger, methodical process.
Step-by-Step Conversion Guide
Step 1: Shutting Off Gas Supply and Preparing Workspace
Begin by turning off the gas supply at the shut-off valve located behind or beneath the cooktop. Rotate the valve 90 degrees to the closed position, then verify the gas is off by attempting to light a burner. You should see the flame die immediately and not reignite. Once confirmed, unplug the cooktop’s electrical connection if it has electronic ignition.
Clear the surrounding countertop and create a clean workspace. Lay down a soft blanket or cardboard to protect the cooktop surface when you flip it over. If your cooktop is drop-in style, you’ll need to disconnect the flexible gas line and lift it from the countertop cutout. For freestanding ranges, pull the unit away from the wall to access the rear panel. Take photos of all connections before touching anything.
Step 2: Accessing the Burner Orifices
For sealed burner cooktops, you’ll typically access orifices from below. Remove the bottom panel using a screwdriver, exposing the gas manifold and burner tubes. Each burner will have a small brass or bronze orifice fitting where the gas line connects to the burner venturi. These are usually accessible but may require removing mounting brackets or heat shields.
Some models allow top-access by removing burner caps and unscrewing the burner heads, revealing the orifices from above. Consult your cooktop’s service manual to determine the correct approach for your model. If you don’t have the manual, search online using your model number plus “service manual” or “LPG conversion instructions.” Never force components apart; if something won’t budge, you’re likely missing a screw or clip.
Step 3: Identifying and Replacing the Orifices
Natural gas orifices are typically marked with a letter (like “N” or “NAT”) and have a larger drill size. LPG orifices are marked “LP” and have a smaller opening. Using your wrench, carefully unscrew the natural gas orifice from each burner, keeping them organized if they’re different sizes for different burners. Some cooktops use identical orifices for all burners, while others vary by burner BTU rating.
Install the LPG orifices by threading them in by hand first to avoid cross-threading, then tightening firmly with your wrench. Don’t over-tighten—brass fittings can strip. The correct torque is snug plus a quarter-turn. Verify each orifice is properly seated and that the gas port aligns with the burner tube. This precision matters; misalignment causes uneven flames and inefficient combustion.
Step 4: Adjusting the Pressure Regulator
Locate the gas pressure regulator, usually near where the gas line enters the cooktop. Most modern regulators have a cap that reveals a reversible plunger or adjustable spring tension. Remove the cap using a screwdriver or adjustable wrench. Inside, you’ll either flip a plunger to the “LP” position or replace a spring with one from your conversion kit.
Some older models require replacing the entire regulator. If that’s the case, you’ll need to disconnect the gas line, remove mounting screws, and install the new LPG-rated regulator. Reconnect everything using Teflon tape on all threaded connections, wrapping clockwise 2-3 times. The tape should be applied to the male threads only, keeping the first thread clear to prevent tape from entering the gas stream.
Step 5: Reassembling and Testing for Leaks
Reverse your disassembly steps, carefully routing gas lines and ensuring no kinks or sharp bends. Before resealing the bottom panel, perform an initial leak test. Mix a 50/50 solution of dish soap and water in a spray bottle, or use a commercial leak detector fluid. Turn the gas supply back on and spray every connection you disturbed—regulator fittings, orifice threads, manifold joints.
Watch for growing bubbles, which indicate leaks. If you find a leak, shut off the gas immediately and tighten the connection. For persistent leaks, disassemble and reapply Teflon tape. Once bubble-free, use an electronic gas detector for a final verification. Light each burner, checking for stable blue flames with minimal yellow tipping. Adjust air shutters on each burner venturi until you achieve a crisp blue flame about 1-2 inches high.
Understanding Orifice Sizing and BTU Ratings
Orifice sizing is a precise science tied directly to BTU output. The formula involves gas pressure, orifice diameter, and specific gravity of the gas. While conversion kits provide pre-sized orifices, understanding the math helps verify correctness. A typical natural gas orifice for a 10,000 BTU burner might be a #46 drill size (0.081 inches), while the LPG equivalent would be a #55 (0.052 inches).
If you’re ever unsure, measure the old and new orifices with a digital caliper. The LPG orifice should be approximately 30-40% smaller in diameter than the natural gas version. Never attempt to drill out or modify orifices yourself; the precise engineering ensures proper air-to-fuel ratio. Using incorrectly sized orifices results in flames that are either too weak (undersized) or dangerously large and carbon-producing (oversized).
Troubleshooting Common Conversion Issues
Yellow, lazy flames after conversion almost always indicate insufficient primary air. Adjust the burner venturi’s air shutter until the flame turns blue. If flames are too small even with correct orifices, verify your regulator is properly adjusted and delivering 11 inches WC pressure. A manometer connected to a test port provides definitive pressure readings.
If burners won’t light or make popping sounds, check for spider webs or debris in the burner tubes—a common issue when cooktops sit unused. Ensure the spark electrode is clean and properly gapped (about 3/16 inch). Persistent ignition problems may indicate the conversion affected the spark module’s ground path; inspect all grounding wires during reassembly.
Post-Conversion Maintenance Tips
After successful conversion, your cooktop requires slightly different maintenance. LPG burns hotter and can produce more moisture, so clean burner ports monthly with a soft brush to prevent corrosion. Check orifice fittings quarterly for loosening due to thermal cycling. The first month after conversion, perform a quick leak test weekly; fittings can settle and require retightening.
Keep your natural gas orifices and regulator components in a labeled bag taped inside the cooktop cabinet. This ensures you or future owners can revert to natural gas if needed. Document the conversion date and orifice sizes in your appliance manual for reference. Schedule a professional inspection after six months to verify continued safe operation, especially if this was your first gas project.
Legal and Code Compliance Considerations
Most jurisdictions classify gas appliance conversion as “gas fitting” work that requires a license. While many allow homeowners to work on their own appliances, rental properties and commercial installations almost always require certified professionals. Check with your local building department about permit requirements; some areas mandate a post-conversion inspection.
Your homeowner’s insurance policy may have specific clauses about gas work. Some policies require documentation of professional installation for claims related to gas leaks or fires. Keep detailed records of the conversion process, including photos and the conversion kit’s certification numbers. If you sell your home, disclose the conversion in writing; failure to do so could create liability issues if subsequent problems occur.
Frequently Asked Questions
How do I know if my sealed burner cooktop is convertible? Most modern sealed burner cooktops are convertible, but not all. Check your owner’s manual for “dual fuel” or “LPG conversion” instructions. Look for a regulator with an adjustable or reversible plunger. If your cooktop is more than 20 years old or a budget import, conversion may be impossible or unsafe. Contact the manufacturer with your model number for definitive confirmation.
What exactly comes in an LPG conversion kit? Standard kits include replacement orifices for each burner (pre-sized for your model), a regulator adjustment spring or plunger, and detailed instructions. Some kits also contain new gas valve limiter caps to prevent over-turning and a conversion rating label to affix near the model number plate. Never use generic kits; orifice sizing is model-specific.
Can I convert back to natural gas later? Absolutely, if you’ve kept the original components. The process is identical in reverse: reinstall natural gas orifices, reset the regulator, and retest thoroughly. Keep all original parts in a sealed bag with desiccant to prevent corrosion. Document the original configuration with photos before conversion to simplify reversion.
Why does my converted cooktop smell like gas when I first use it? A slight odor during initial use is normal as manufacturing residues burn off and new components “seat.” However, persistent gas smell indicates a leak. Perform immediate soap-bubble testing on all connections. If you can’t locate the source, shut off the gas and call a professional. Never assume a gas smell will dissipate on its own.
Will converting to LPG affect my cooktop’s BTU output? Properly converted, your cooktop should deliver nearly identical BTU ratings. LPG contains more energy per cubic foot than natural gas (about 2,500 BTU/cu ft vs. 1,000 BTU/cu ft), which is why orifices are smaller. The regulator adjustment ensures the higher energy content is delivered at the correct rate. If your flames seem weaker post-conversion, the regulator likely needs fine-tuning.
Do I need to convert my oven and broiler too? If your appliance is a range with an oven, yes. The oven and broiler have separate orifices and often a different regulator or pressure setting. The conversion kit should include these components. Skipping oven conversion creates the same hazards as with cooktop burners—dangerous flame size and incomplete combustion.
How often should I test for leaks after conversion? Perform a comprehensive leak test immediately after conversion, then again after one week of use, then monthly for the first three months. Thermal expansion and contraction can cause fittings to loosen. After the initial period, test quarterly. Any time you smell gas or after moving the appliance, conduct an immediate test.
What causes a “popping” sound when I light a converted burner? Popping indicates delayed ignition, usually caused by too much gas buildup before the spark ignites it. This can result from incorrect orifice size, improper air shutter adjustment, or a weak spark. Check that you’re using the correct LPG orifices and that the spark electrode is clean and properly positioned. Persistent popping requires professional diagnosis.
Can I use Teflon tape on all gas connections? Use yellow Teflon tape specifically rated for gas lines, never white plumbing tape. Apply only to male tapered pipe threads (NPT), not to flare fittings or compression fittings. Wrap clockwise 2-3 times, keeping the first thread clear. For flare fittings, rely on the metal-to-metal seal; tape here can prevent proper seating and cause leaks.
Is it normal for LPG flames to be slightly noisier than natural gas? Yes, LPG flames can produce a subtle “roaring” sound due to the higher pressure and different combustion characteristics. However, excessively loud flames or whistling indicates a problem—likely an air shutter that’s too open or a partially blocked orifice. Adjust the air shutter incrementally while the burner is lit until you achieve a quiet, stable blue flame.