How do i clean the orphis on a propane furnace?

You will need to pull out the burner embly and gently clean the nozzle that the gas flows from during operation. Open end wrenches are good for this task, you may need a flat or philips screwdriver as well. You can use a small piece of wire to clean the opening, as long as it is not larger than the diameter of the opening of the gas orifice. There may be white ash residue on the end of the opening, and inside the opening as well. Use the small wire to knock the debris away. Be very careful to not widen the hole; it is soft br, and if you make it larger, the flame will burn differently than the machine is designed for.