I am not sure I understood exactly what you are doing but wanted to make a few points. I looked through the manual and saw they want you to keep it at least 6 inches away from any combustible surfaces, make sure you heed that warning - it is not designed to be used in homes, so you can't put it up against anything that will burn. Second, 25,000 btu is not a lot for a propane system, many outdoor grills go 75,000 btu or higher when you add in all the burners, and they commonly run off a 10 foot flex hose with a disconnect, so I don't think a few 3/4 inch elbows will cause that much of a problem. I saw the description of how the supply must be run in the manual, but the manual seems to cover all their models, including the F3 series ovens - which I assume means the F3218 ( according to the catalog that is 242,000 btu ) . F330 ( 174,000 btu ) all the way up to F3226 ( 300,000 btu) The product catalog says they use a 3/4 inch supply, so probably to make things consistent, that is what they use for all their products, even the pizza oven that only uses 25,000 btu - so if it were me, personally, I would not think that a few elbows are a problem. The manual does tell you to measure the pressure at the appliance. If you think it is starved, and you ruled out the issue Jet raises with the OPD on the propane tank, I would call a small appliance repair company, or a gas certified installer to come check the pressure at the oven to see if it is okay and check the flame to make sure you are getting enough air and gas.