Troubleshooting a Lennox Oil Burning Furnace

Check the Lennox furnace to verify it is turned on. Push its reset button, which should start the furnace manually. Do not push the reset button more than once or twice, however, or you may overload the furnace's combustion chamber with oil.

Check the circuit breaker or fuse that is associated with the furnace if the furnace doesn't start or starts and then shuts down too soon. If the circuit breaker tripped, reset it by switching it to the "on" position. If the fuse blew, replace the fuse. Try starting the furnace again. If the problem persists, the furnace may have a wiring problem.

Check whether or not the furnace has oil in its tank. Most oil tanks have a gauge that allows you to check the fuel level. If your furnace's tank does not have a gauge, then insert a 6-foot long straight stick into the fill valve on top of the tank to check the oil's level. The furnace won't operate if it is out of fuel.

Inspect the furnace's thermostat. Ensure it is turned on and has fresh batteries. It should be set to "heat," and the set-point needs to be above the room's current temperature or the furnace will not activate.

Check your home's registers to verify they are not closed or blocked. If registers are shut or blocked by furniture or other items, the furnace can overheat and shut down.

Check the furnace's filters. Dirty filters can have an effect similar to blocked registers, leading to overheating and making the furnace shut down soon after igniting. If the furnace uses a permanent filter, remove the filter, clean it and put it back in the furnace. If the furnace uses a disposable filter, replace the filter with a new one.