Lynx Gas BBQ Grill Conversion To Natural Gas or Liquid Propane Fuel.

by grillrepair on March 15, 2014

natural gas and propane bbq grill orifices

Although the same orifice fits many grills, many valves, the hole drilled for LP or for NG can be very obviously different.

Convert Lynx Barbecue Grill To NG or LP.

Lynx LP and NG Conversion Orifices

To convert any barbecue grill from one type of gas to another type of gas we need to change the regulator and the orifices.  Most barbecues have one regulator although it is not uncommon for a gas grill to have two regulators.  Because natural gas has a much larger molecular mass than LP and because NG is often at least partially mixed with oxygen, an orifice drilled for natural gas will always be much larger than an orifice drilled for the same BTU rating for propane.

The regulated pressure is also different for LP and NG but among NG regulators there is a range of pressure settings from two-inches of water column displacement to 14 inches water column displacement that is considered normal.  This is because a natural gas line may have a route many miles long affecting the pressure leading up to one property or one appliance.  Also if a particular property has several appliances pulling from the mail NG line then the pressure may need to be higher to push the gas throughout the property to these various appliances.  The gas barbecue grill is not affected by a natural gas line with a higher or a lower gas pressure so long as the orifices are drilled according to the amount of pressure passing through the orifice.

Logically this makes simple sense.  If we need a specific amount of gas passing through a hole, if the gas line is under high pressure the hole will need to be smaller just as the hole will need to be larger for a lower pressure.  Regardless of the pressure set by the regulator on the barbecue grill designed to finction with the gas lines on the property the orifices will need to be drilled to the corect BTU setting based on the amount of pressure passing through the control valves.

LP or liquid propane is almost always regulated at the same eleven-inches of water column displacement.  In the tank — whether a portable tank or a huge tank on the property — propane is a freezing cold liquid.  Liquid propane vaporizes — boils — in the cylinder because of the temperature outdoors and because of the difference in pressure inside the cylinder.  Our low-pressure gas appliances will pull this vaporized propane into the grill to burn as fuel.  Since Propane is a vaporized gas there is no oxygen mixed with the gas as it feeds into the grill so we must adjust the air shutter on the burner to allow oxygen to mix with the propane as the burner is filled with gas.

In addition to changing the regulator on a barbecue grill, when we convert a gas grill to LP or to NG we have to change the orifices in the grill.  Every control valve, every burner will have an orifice that needs to be drilled to allow a specific BTU (amount of gas) when under the specific amount of pressure set by the regulator.

A Lynx gas barbecue grill has cast brass burners for the main burners in the grill.  These cast brass burners are designed to burn 25,000 BTU’s per hour.  Grill companies use the term “BTU” to denote an amount of gas even though a “British Thermal Unit” is truly a measurement of actual heat.  This is a little bit confusing and not

Lynx BBQ grill control valves and burners of brass and iron

All the Lynx control valves attach to the gas manifold pipe and pull gas which passes through the orifice to enter the grill burners.

exactly correct because the result of the heat that can be measured in a barbecue or a grill or a smoker is largely affected by the type of burner, shape of the burner, firebox and hood design and by the way the appliance uses materials to conduct and radiate heat.

In addition to the main cast brass burners in a Lynx BBQ grill some models will also have an infrared rotisserie burner, some have an infrared pro-sear grill burner, and some models will have a smoker burner installed below a tray used to hold wood chips while cooking.  Every burner is controlled by a control valve and every control valve passes gas to the burner through an orifice which determines the maximum amount of gas that can flow into that burner.

To convert a Lynx barbecue we need to change the orifices — all the orifices.

To remove and replace the orifices in a Lynx gas grill we will need to remove the cooking grates, briquette support shields and the burners in the bottom of the firebox.  The orifice is mounted to the tip of the control valve and the tip of the control valve is mounted inside the venturi tube of the grill burner so we cannot get at the orifice while the burners are in the grill.   Once the burners are out of the grill we should be able to look into the control panel from inside the grill.  Inside the front firewall of the barbeque each burner passes into the control panel through a hole in the front firewall.  We should be able to reach into this hole with a socket and ratchet set to unscrew the orifice from the tip of the control valve.

tec infrared grill orifice from inside the grill with the burner removed

From inside the gas grill we can look through the hole where the burner passes into the control panel to see the valve and the orifice.

We should be able to reach through the burner hole and unscrew the orifice but many Lynx models have an orifice almost two-inches long which means our socket has to be very deep.  Most deep sockets are designed around sizes for vehicle spark plugs but a grill orifice is much smaller than a spark plug so it is not abnormal to be unable to get Lynx orifices out this way.

If we have these deep orifices which are main burner orifices on Lynx models 30, 42 and 56 inches wide  then we’ll usually need to remove the entire front control panel to get at the orifices.  The picture above shows a lynx grill with the control panel removed so we can see the control valves, gas manifold, we’ll see the ignition assembly and with the burners removed we will see the orifices at the tip of the burners.

With the control panel removed we can use an open end wrench or an adjustable wrench or remove the orifices and replace the orifices with the new orifices to convert the Lynx valve to LP or NG.  As the image above shows the valves are easy to see and easy to get to once the control panel is gone.  If the Lynx has a rotisserie or a smoker burner these orifices are not so easy to get removed.  The control valve that feeds gas to the smoker burner in a Lynx does not have an orifice threaded to the end of the valve like the main burner valves.  Instead the smoker valve has a gas line attached to the end of the valve and the other end of this gas line is attached to the orifice which is inserted into the front of the smoker burner.  To get to the smoker burner orifice we will need to ignore the valve and go right to the smoker burner to unscrew the elbow connection and pull the gas line out of the burner to be able to unscrew the old orifice and attach the new orifice.

Lynx infrared rotisserie orifice installation and conversion

Gas line compression elbow and Lynx rotisserie orifice attaches to the stainless burner venturi in the back of the grill.

The rotisserie burner is the infrared burner installed in the back wall of the grill.  Depending on the model of the grill some Lynx models will have a small access panel in the back of the grill so we can get to the gas line inserted into the rotisserie burner.   On Lynx models without the access panel we will need to remove the infrared burner.  Once the infrared burner is removed the orifice is accessible right inside the rectangular opening where the rotisserie burner mounts int he back wall of the grill.  Again we simply unscew the old orifice and install the new one and then replace the burner.

Concerns about liability have caused a lot of barbecue grill manufacturers to disseminate a policy to dissuade anyone from converting a grill from LP to NG or from NG to LP.  A LP regulator attached to a manifold with valves that still have NG orifices will generate a flame 10-12″ tall from the burner because the NG orifice opening is gigantic when compared to the LP orifice opening.  There is a real danger to doing this incorrectly.  However, compared to other gas line repairs converting a barbecue grill from one gas type to another is very easy.  The process and the idea of the conversion is simple.  The process of converting the grill is also simple.  The only part of the repair that is not simple is getting the control panel off and getting the rotisserie burner removed and even this is very straight-forward.

Majestic Grill Parts can be reached anytime at:

954-2-GRILL-2  which is also: 954.247.4552

If you need any assistance with your Lynx barbecue grill conversion or anything else please contact us.  It is a lot easier and a lot safer to pass a few emails back and forth or have a conversation over the telephone than it is to do this — or any gas appliance repair — wrong and have to start all over again.


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