If you're like most people, you learned at an early age that smoke means fire, and that if you ever smell smoke, you should get out of the home immediately. While this is certainly a good safety precaution in most cases, if the smoke in question happens to be coming from your oil-burning furnace, you need to know a little more. As long as you catch it early, smoke billowing from an oil-burning furnace is not necessarily a sign you need to evacuate immediately. What you do need to do is stop, evaluate the situation, and calmly try a few means of fixing the problem before calling the repairman. Follow the steps below for best results.
Assess the situation.
If you've come home to a house filled with smoke, by all means, go outside and call the fire department so you can be sure nothing else has caught fire and is contributing to the issue. On the other hand, if you were home when the smoking started and know for a fact the smoke is only coming from the furnace, you can hold off on calling the fire department and proceed with the steps in this guide.
Turn off the furnace.
Simply walk up to your thermostat, and turn the heat off. This will give the smoke a chance to dissipate and the furnace a chance to cool off before you start fiddling with anything. If you have windows in your basement, open them to let the smoke out. Try not to spend too much time in the basement while it is smoky, since the smoke contains carbon dioxide and other chemicals you won't want to breathe in excessively.
Check the chimney.
Once the smoke has dissipated and the furnace has cooled (this typically takes two or three hours, so be patient), have a look down the chimney. If it is difficult to get onto your roof due to weather or a steep pitch, you might be able to get a look up the chimney by removing the metal tube that connects it to your furnace. However, this will depend on the setup of your furnace. If you're unable to check the chimney, you should call an HVAC professional at this point.
Look for any blockages in the chimney, as these are a common cause of smoking. Birds love to build their nests in chimneys, and sometimes leaves can blow in. You can try removing a blockage yourself by sending a long, stiff wire with a hook on the end up or down the chimney, grabbing the material, and pulling it out.
Clean the flue connector.
The flue connector is the metal piece that connects your furnace to the chimney. If it gets too caked with soot, it can cause your furnace to smoke. Disconnect this part of your furnace (all you typically have to do is unscrew it). If it looks black and dirty, wipe it clean with some cloths or a stiff brush. Put it back into place, and try running your furnace to see if you've solved the problem. If you still have smoke, turn the furnace back off, let it cool again, and then move on to the final step.
Check the oil filter.
If the chimney and flue are clear, the next possible culprit is your oil filter. If you have not changed it recently, it may be clogged and causing impurities to burn along with the oil, leading to the smoke. To change the filter, look in your furnace owner's manual to locate the filter housing. Unscrew the filter housing, remove the filter, and take it with you to your local hardware store to make sure you buy another of the same type. Put the new filter back in place, screw on the housing, and then try starting the furnace. If no smoke appears, you have solved the problem.
If even changing the filter does not fix the problem, then it is time to call in the pros. Faulty burners can cause smoking, too, and this is an issue that will need to be handled by an experienced HVAC technician from a company like Self Heating Cooling.