Oil furnaces have distinct personalities. Many people love their oil fueled furnace because of the cozy warmth it quickly produces. There are some common problems, though, and here it what to look for when these problems arise with your unit.
You can expect a good quality oil furnace to last for up to 30 years. Most problems that arise are repairable for a reasonable cost. If it is time to replace your furnace, you should consider fuel costs for your area, as well as the whether or not an oil furnace is clean enough for you.
The first problem you may encounter is an oil smell. This may be particularly prevalent with a brand new unit. Actually, you may have nothing to worry about, because the heat exchangers come from the factory coated in a protective oil. This oil will burn off within a week or two and the smell should dissipate. If you have an older unit producing a smell, you may have a cracked heat exchanger. A CO detector is a must to make sure that you do not accidentally poison your family. Other smells may originate from a motor going bad. A fan motor can overheat and produce an acrid odor. If you smell your furnace at the bottom, where the motor resides, and you smell the same smell, that could be the source. Your oil burner too, has a motor which can go bad in this manner.
Next, you may experience a smoking or soot issue with your oil furnace. Smoking is caused by improper combustion. You have to have the right fuel/air combination and it has to be ignited fully to alleviate smoking. If there is smoke when you start your furnace, then you are having a delay in ignition. Your nozzle may be clogged or your electrodes may need to be adjusted. You will also want to check your filters. It is going to require a service call to have your unit properly adjusted. If you notice soot accumulating in your home, you could have a crack in your heat exchanger. Have this professionally attended to at once, as this is a serious source of carbon monoxide gas in your home.
If you oil furnace is cutting off unexpectedly, there are several issues to check. If you have an older unit with a pilot light, then examine your thermocouple. This is a copper rod near your pilot light on older units. It should be shiny and clean. If it is not, then it will not properly tell your unit that the pilot flame is present. An oil service technician would make sure all power, fuel and flame was off to your unit and then clean the thermocouple with steel wool, or they may simply replace it. If your oil furnace flame starts and then dies gradually, then you may need your oil filter replaced. Other considerations for your unit cutting off may be water in your fuel, transformer problems or bad electrodes not giving a proper spark. One final culprit may be clogged nozzles not allowing proper fuel flow.
Sometimes you may have trouble restarting your oil furnace. Make sure you have followed the instructions properly for bleeding your fuel line. If you have tried to restart multiple times on a newer unit, it may have a memory chip which will "lock-out" unit from multiple restart attempts. You can easily reset the lock-out by cutting the power off for 2 minutes. If the unit seems to reset but still will not work, then check your motor. There can be a separate reset button on your motor as well.
These issues will cover most of the problems which can be addressed by the homeowner. More extensive problems will definitely require a professional service call. Above all, be safe and make sure you do not have carbon monoxide being emitted into your home by your oil furnace.