How to Restart an Oil Furnace. Restarting your oil furnace can be as easy as pushing "reset." Some furnaces will even restart on their own after refueling. Follow these steps to restart your oil furnace.
Turn off your furnace and find the bleeder valve. It resembles a grease fitting and often is on the left side. It should be easy to identify since the fuel line runs into it.
Unscrew the bleeder, but do not disconnect it. Place your metal container underneath to catch any access fuel, as it may spray out as the air escapes.
Simultaneously turn on and loosen the valve to get furnace going. Pressing the "reset" button might also be necessary.
Tighten the valve, although not all the way, and listen for the furnace to turn on. Use a wrench to tighten the valve all the way once the furnace has started.