Why every grill leaves the factory set for one gas
Propane and natural gas reach a grill at very different pressures, so the parts that meter them are sized for one or the other. Lynx's installation table lists natural gas at a 7-inch water column maximum and 4 inches under full load, and propane at 14 and 11 inches. Its manual explains that both the regulator and the manifold orifices have been tuned for the gas named on the rating plate, and that the grill should not be run on any other.
The orifices are the small brass fittings at the end of each burner valve, and each one has a hole drilled to suit its gas. A grill set for propane and piped to a natural gas line is feeding the wrong gas through holes and a regulator meant for something else. That is why every maker that allows a change supplies a kit of parts, not just a new hose.
Reading the rating plate first
The rating plate carries the model and serial numbers and the gas type the grill is set for. Lynx lists two places to look, on the underside of the drip tray and on the heat shield behind the front panel; other makers name their own spot in the manual. Photograph it before you ask anyone about conversion, because the answer starts with the exact model.
Source: Lynx — Professional Grill Care, Use and Installation Manual — Water column table for natural gas and propane; regulator and manifold orifices tuned to the gas on the rating plate; do not operate on another gas; rating plate under the drip tray or on the heat shield; conversion kit installed by a qualified technician; supply line sized for total BTU, not under 3/4 inch ID; accessible shutoff by a qualified plumber; NFPA 54
Whether you can convert a propane grill to natural gas: what the makers say
There is no single rule, and the answer can differ between two product lines from the same maker. Some grills are designed to take a kit for the other gas; others are sold as separate propane and natural gas models that are not meant to be changed at all. Only your model's own manual settles it.
- Lynx: converting to another gas requires a conversion kit from Lynx or the dealer, installed by a qualified technician.
- Blaze: all gas conversions must be performed by a qualified technician, and its conversion pages are marked for a gas professional only.
- Weber Spirit: do not modify the grill; converting or using natural gas in a propane unit, or the reverse, is unsafe and voids the warranty.
- Napoleon: its warranty excludes any conversion the maker has not approved, and burner air adjustments are for a qualified gas installer.
When the manual says no
If the maker rules conversion out, the choice is between staying on propane and buying the natural gas version of a grill. Hardware-store adapters and universal orifice sets do not change that; the grill's tested configuration is what the maker's instructions and the rating plate describe, and nothing else.
Source: Lynx — Professional Grill Care, Use and Installation Manual — Water column table for natural gas and propane; regulator and manifold orifices tuned to the gas on the rating plate; do not operate on another gas; rating plate under the drip tray or on the heat shield; conversion kit installed by a qualified technician; supply line sized for total BTU, not under 3/4 inch ID; accessible shutoff by a qualified plumber; NFPA 54; Blaze — Professional Series Use and Care Guide — All gas conversions by a qualified technician; conversion steps remove grids, flame tamers and burners and change the fragile orifices; natural gas regulator at 4.0 inches water column; leak check after conversion; secondary tank regulator at about 11 inches; grill regulator limited to 0.5 psi inbound; Weber — Spirit natural gas grill owner's manual (8653810, US) — Do not modify the grill; converting or using natural gas in a propane unit or the reverse is unsafe and voids the warranty; quick-disconnect never pointing upward; model-specific hose; disconnect during high-pressure testing of the supply; Napoleon — Built-In Series owner's manual (N415-0601) — Warranty excludes conversions not approved by the maker; air shutter adjustment must be done by a qualified gas installer
What the gas technician does during a conversion
The maker's conversion instructions are written for the technician, and they touch every gas-carrying part at the front of the grill. Blaze's procedure, for example, starts with removing the grates, flame tamers and burners to reach the valves, then changes the brass orifice at the end of each valve for the one supplied in the kit, a step it warns needs great care because the fittings are fragile. The regulator is converted or replaced to suit the new gas, set to 4 inches of water column for natural gas on Blaze grills, and the low-flame setting and air shutters are adjusted so the flame burns properly on the new fuel.
The job ends with a leak check on every joint that was opened and a flame check on each burner, the side burner and any rotisserie burner included. Blaze's instructions close with exactly that reminder.
Burners that are easy to miss
A grill head can have more valves than the knobs on the main row suggest: a rear infrared rotisserie burner, a sear burner, a smoker burner or a side burner on the cart. Each has its own orifice and each must be converted, which is one more reason the kit for your exact model matters.
Source: Blaze — Professional Series Use and Care Guide — All gas conversions by a qualified technician; conversion steps remove grids, flame tamers and burners and change the fragile orifices; natural gas regulator at 4.0 inches water column; leak check after conversion; secondary tank regulator at about 11 inches; grill regulator limited to 0.5 psi inbound
The natural gas line is a separate job
Converting the grill is half the work; the other half is bringing a gas line to it. Lynx asks that only qualified professionals do the plumbing, that the supply line be sized for the total BTU of every appliance it feeds and never be smaller than 3/4 inch inside diameter, and that an accessible shutoff valve be installed by a qualified plumber. It also asks installers to follow the National Fuel Gas Code, ANSI Z223.1/NFPA 54, or local codes.
Weber's natural gas cart grills connect through a quick-disconnect fitting, which its manual says may point horizontally or down but never up, so water and debris do not collect in it. The grill uses the model-specific hose fitted at the factory, and during any high-pressure test of the house piping the grill and its shutoff are disconnected.
- The grill's model and its BTU rating from the plate
- Every other gas appliance the new line will also feed
- Where the shutoff valve can sit and still be reached with the grill in place
- The manual's page on the connector and hose for that model
Going from natural gas back to propane
The reverse conversion has its own traps. Blaze explains that running a converted grill from a portable tank needs a second regulator on the tank set to about 11 inches of water column, and that the regulator on the grill can accept no more than 0.5 psi coming in, so a larger fixed propane supply may need extra regulation first. Your propane supplier confirms the pressure at the line.
Source: Lynx — Professional Grill Care, Use and Installation Manual — Water column table for natural gas and propane; regulator and manifold orifices tuned to the gas on the rating plate; do not operate on another gas; rating plate under the drip tray or on the heat shield; conversion kit installed by a qualified technician; supply line sized for total BTU, not under 3/4 inch ID; accessible shutoff by a qualified plumber; NFPA 54; Weber — Spirit natural gas grill owner's manual (8653810, US) — Do not modify the grill; converting or using natural gas in a propane unit or the reverse is unsafe and voids the warranty; quick-disconnect never pointing upward; model-specific hose; disconnect during high-pressure testing of the supply
