How to Troubleshoot Black Smoke From an Oil Furnace


When an oil-burning furnace emits smoke that is black, grey, or thick, it is a warning that there is a significant issue and should be treated as an emergency. This is true regardless of whether the smoke is coming from the chimney, the exhaust vent, or the combustion box. If the issue is not located and fixed right away, the furnace has the potential to either create an explosion or start a fire within the building.

Protect Yourself

There are numerous instances in which the black smoke that is produced by an oil furnace does not cause any discomfort to your skin and does not irritate your eyes or nose. However, despite this, it is still toxic since it includes carcinogens and carbon monoxide, both of which may lead to major health issues. Stay away from the front or door of the furnace since it has the potential to blow open if there is too much pressure within. In the event that there is a fire, explosion, white vapour cloud, or any other kind of emergency, call the fire department immediately.

Incomplete Ignition

When oil is pumped into the combustion chamber but it is not instantly ignited, a phenomenon known as incorrect ignition occurs. This phenomenon is also known as puff back. When the oil finally catches fire, it does so in a brief burst or miniexplosion that results in the production of a massive cloud of black smoke. Puff back is easily identifiable by the leaping flame that it produces when the fire spreads to the dispersed oil droplets. It happens sometimes that the flame will follow the oil out the furnace door, which may lead to a fire in the home. The burner and the furnace are at risk of being destroyed if the explosions become any stronger, and the situation might become hazardous if this happens.

After Fire

The after fire may have been caused by faulty burning or a leak of oil. Even after the furnace has been turned off, the little quantity of oil that pools at the bottom of the combustion chamber and continues to burn even after the furnace has been turned off. It rapidly consumes the oxygen that is present in the combustion chamber and creates dense clouds of black smoke due to the fact that it is not regulated and the fan has been switched off. An after fire is created when there is still a flame present after the furnace has been turned off.

Quick Action

As soon as possible, cut off both the power and the fuel supply that the furnace is receiving. In the vast majority of instances, an emergency power shutdown switch will be located someplace in close proximity to the heater. Nevertheless, cutting off the flow of oil is an essential step to take. The majority of furnaces have two valves that may turn off the heat supply: one at the burner, and another at the tank. Both should be turned off as soon as it is safe to do so. Do not restart the heating system until a qualified technician has inspected it and given you the all clear.