Grill Repair: Compression Adaptor to Extend Valve and Orifice with Gas Line

barbecue control valve compression flare adapter

instructions for adding gas line for control valve

In a typical barbecue the control valve attaches to the manifold pipe and the manifold pipe is attached the the gas line. The control valves attach to the manifold so the valve is able to pull from the gas flow and spit gas into the barbecue burner. On the tip of the control valve, inside the control panle and opposite the knob we turn for gas the orifice is attached to the valve and the orifice inserts into the burner so the gas flows right into the burner.

There have been barbecues that needed an extension. Some models of kalamazoo, turbo, captain cook and others have the control panel set forward so the valve is not close enough to the burner for the orifice to attach the valve and the burner. In these instances the valve will have a gas line attached to the tip instead of an orifice. The gas line is generally luminum or copper and will bend and extend to wherever the burner needs to be mounted. On the far end of the gas line the orifice is mounted so it can insert into the burner venturi tube and spit gas right into the burner.

When this style of connection comes from the factory the gas lines are cut to size and threaded to fit the valve on one side and the orifice on the other side. However, years later when these items need to be replaced and the manufacturer is out of business or the true manufacturer is in China and does not have replacement parts available how do we repair these grills?

Compression fittings can be used in place of flared fittings or threaded gas lines and will attach to a smooth sleeve of aluminum gas line without leaking.

Imaage one above shows the tip if the gas line and the compression adapter. This adapter is 1/4 inch compression on one side and 1/8 inch threaded pipe connection on the other side.

Image Two: When the compression fitting is unscrewed there is a small flare inside the hew-head. This is soft brass and designed to be smashed inside the fitting when attached.

Image Three: Slide the hex-head onto the aluminum or copper gas line and then slide the flare nut as seen in this image. The flare should be 1/8 inch to 1/4 inch from the edge.

Image Four: Attach the two sides so the soft brass is set in from the edge inside the hex-head nut and the adapter so when these two pieces are tightened the brass will be smashed between them and flare into place. When loose the entire assembly will slide off the aluminum gas line but once tightened the soft brass will smash into place holding tightly to the aluminum gas line. You could force it to break the seal so be gentle but this will stop gas from leaking around the fitting. The soft brass squeezed between the nut is the gasket.

Image Five: Now the adapter is tightly attached to the gas line and will not leak so we can screw on the control valve. Different control valves have different threading. This control valve is threaded inside and outside the opening for the orifice so a hood style orifice or a spud style orifice could be used. Likewise a 1/8 inch pipe thread can be attached as we have done here or a 1/16 inch male

adapter could have been used for the other side of the adaptor instead.

Image Six: Using the exact same steps: we have attached a compression-to-1/8 female on the side where the male thread of the valve will attach to the female thread of the compression adapter and on the other end of the aluminum gas line we will attach an adaptor that is 1/4 inch compression on one side and 1/8 inch male thread on the other side. The steps are the same to attach the compression side to the gas line tightly.

Image Seven: Now the threaded end of the gas line has the exact same threading the original control valve for the gas grill has and the orifice can be attached to the fitting. This has extended the length of the control valve and allows us to move the connection up, down, right, left or wherever we have to insert the orifice into the barbeque burner.

As a last note propane is always in a cylinder of some kind and is regulated closely at 11″ water column displacement. Liquid propane is a liquid with a low boiling temperature (a boiling temperature that if considered freezing for humans) and the liquid boils into a vapor inside the cylinder. Propane is a tight, cold, small-molecule gas that requires only a small gas line, a small hole in the orifice. Natural gas is always already a gas pumped throughout entire neighborhoods, entire cities. Natural gas is a large-gas, meaning the molecules are large and natural gas lines are often several miles long. NG will be pressurized much higher than LP in order to push across town to its various locations and the inner diameter of a NG line is often double and triple the inner diameter of a LP gas line.

The aluminum or copper gas line we use is usually not more than a few inches long but it is smarter to use a larger inner diameter hose than a smaller one and hope it works so the gas pressure does not bottle-neck at the connection and stop the gas barbecue grill from cooking properly.