If you have an oil boiler or furnace that does not seem to be running as quietly and smoothly as it once did, then it may be time to call a company that can perform a furnace service or a heating tune up. You can also perform a few simple tasks yourself to make sure your furnace is running as well as it should.

Change the Filter

Oil boiler heating systems have small filters that remove all the dirt, rust, and other contaminants that flow through the oil line with the fuel. This filter is similar to the oil filter in your car, and it contains media that collects all the debris so clean oil can move to your furnace. Heating oil is likely to pick up contaminants from the oil line and the tank. Also, heating oil will begin to congeal as it becomes cold and will develop wax. Some of this wax will be filtered out of the fuel.

When the fuel filter becomes caked with debris, contaminants can no longer be filtered out and the dirt travels to your furnace. The materials can then partially clog the spray nozzle that releases the fuel into the combustion chamber. The fuel will sputter out of the nozzle when this happens. This creates an inconsistent flame and you may hear a roaring sound that intermittently becomes louder and quieter as your boiler runs. If you hear this, then it is wise to change the filter as soon as possible. If contaminants continue flowing through the fuel line, the hole in the spray nozzle can become clogged. Your furnace will no longer fire when this happens and the nozzle will need to be replaced.

You will see the filter casing attached to the furnace oil line. The casing will sit close to your furnace. Twist the oil shutoff valve that sits just behind the oil filter to stop the flow of oil through the oil line. Use a wrench to remove the bolt on the top cover of the filter, remove the top part of the casing, and gently remove the filter. Filters are typically fiber varieties that come in slightly different shapes and sizes. Look at the shape of the filter and also measure the height and width. This will help you to purchase a new filter from your local home store. Once you buy the correct replacement filter, slip it into the canister housing, replace the top cover, and start your boiler.

Look for Leaks

Sometimes an oil boiler will run rough when there is not a consistent supply of oil running to the furnace. For example, pockets of air may travel through the fuel line and stop the flow of oil intermittently. When this happens, you will hear the normal furnace rumbling sounds subside for a few minutes and then become strong again. If there is air in your line, then you may also notice that the boiler has a hard time firing. You may need to press the reset button from time to time to get the boiler to turn on. 

This type of problem is often caused by a leaking oil line, and you should look for signs of leaks. Leaks are most common where the oil line attaches to the oil tank, the filter, and the furnace. The oil line will connect to all of these areas with nuts. These attachments can loosen over time and allow fuel oil to leak out. Inspect all of these areas closely with a flashlight. If one of the nuts appears wet, then it is probably loose. Use a wrench to tighten it. 

If you do not see any signs of a leak, then there is a possibility that there is a small hole somewhere along the oil line. You should contact your heating specialist to inspect the line so the hole can be located.