Originally Posted by Meat & Heat
The burner orifices should be marked with either an lp or ng on them, most of the time they are stamped in sometimes color coded. If you have the manual it should tell you.
You are correct that is a propane regulator, a natural gas regulator will have either a 1/2ips or 3/8ips female threaded end on it. I would call the manufacturer back and get infor on the orifices then start there.
If you run propane with the natural gas orifice the flame will be about three times the size as the hole is larger than a propane one.
That's right, since the heating value of NG is around 1,000 btu/scf and the heating value of propane is about 2,500 btu/scf.
I think the original poster wants to run NG. I'm not giving you any advice, and YMMV, but if that were mine, I'd remove the propane regulator and short piece of attached hose, then I would simply run my flexible NG hose to the grill and try it out. If the original seller converted it to run propane, you won't be able to get enough NG to the burners to run on "high". I'm an Engineer, and I do not recommend you do what I would do here.