When your oil furnace is operating correctly, you should see little to no smoke coming from it or your chimney. On occasion, a small amount here and there isn't unusual and can be affected by the grade of fuel you are using. But if you see constant black smoke, there's a problem with your oil furnace that could potentially be dangerous. Depending on your level of expertise, you may be able to perform some maintenance and troubleshooting steps yourself, but the furnace will need to be repaired before using it again.
Not Enough Chimney Oxygen
If there is any blockage in your chimney, the loss of air flow can cause black smoke to erupt from your furnace even if the furnace itself is working just fine. Check your chimney for birds nests, soot buildup or other blockage. If you don't have a protective cover for your chimney, install one to minimize the number of creatures or large blockages ending up inside.
Burner Tune-up Necessary
Burner tune-ups are a part of standard maintenance in which the nozzle and oil filter are changed and the filter cartridge is filled with fresh oil. If either are old and not working correctly, they can overheat and emit smoke. This is especially important for first-time maintenance if your furnace doesn't have the right nozzle installed. This is also a good time to make sure that the furnace's oil pressure is correct, because if it is too high it could cause multiple problems.
An incomplete ignition occurs when oil is pushed into the combustion chamber but isn't immediately lit. As a result, when the oil is lit after a small delay, it lights in the form of a small burst, which produces smoke. This can be extremely dangerous, as the leaping fire can potentially reach your house.
A similar problem is an after fire, where oil that has dripped to the bottom of the combustion chamber lights even after the furnace shuts off. When a fire burns inside the chamber while the furnace isn't on, it consumes all the oxygen inside and produces smoke.
Dirty Flue Connector
A flue connector usually has a bit of soot and ash inside, but an actual buildup to the point where blockage is occurring can cause multiple operational problems as well as produce some smoke. Loosen your flue connector and take a look inside and clean as necessary.
If you aren't comfortable working on your furnace yourself, or if you believe you have a serious problem, call in for maintenance and repairs immediately. In the meantime, shut off power to your furnace to prevent it from turning on, and let it cool before working on it or trying to troubleshoot the problem.
For more information, contact a business such as Cash Oil.