I ran out of fuel oil and had the local fuel oil co. bring a delivery; now I think I have air in the inlet feed of my line to the furnace; how do I bleed this unit, it is a intertherm mac 1280 series unit

You will need some type of container (coffee can works well) and a piece of small tubing (a straw will work in a pinch). Locate the purge nipple on the fuel pump - usually resembles an automotive brake bleeder fitting. Put a wrench on the fitting, followed by the straw, with the container in place to catch the fuel. Start the burner and open the nipple to allow air to escape - you may have to reset the primary control a few times, but continue until a solid stream of fuel comes out. Close nipple between purge attempts if primary control locks out. Once purged the burner should fire. If it does not, the nozzle and/or fuel filter may be fouled and will require professional servicing.

FYI, by letting your tank run dry, you run the risk of sucking up sediment and plugging things.

If you ran out of fuel it is always best to change the filter also.