Depending on the problem, troubleshooting a kerosene heater could include refilling the fuel tank or replacing the batteries. Additionally, the wick may need to be lowered or replaced.
If a kerosene heater doesn't light, first check the fuel level, and refill if necessary. If the igniter is not glowing, replace its batteries. Lower the wick by turning the adjuster knob; the igniter should touch the top of it. If there is a chance that the kerosene may have water in it, drain the fuel, remove the wick and replace it, and refill the tank with new kerosene.
If the heater is emitting smoke, lower the wick to decrease the height of the flame. Place it in a spot without drafts or use the burner knob to move the burner to a level spot over the wick. If smoke still occurs, drain the kerosene, change the wick and fill the tank with new kerosene.
If a kerosene heater's flame flickers or extinguishes completely or if the wick stick needs to be adjusted, drain the fuel, change the wick, and refill with a small amount of fresh kerosene. Light the heater, and let it burn until the fuel tank is empty and the flame begins to die. Do this with the wick in the most elevated position possible. After an hour, light the wick again, and let it burn out. After the heater cools, remove the metal guard and take the ash from the wick with a toothbrush.
If the wick doesn't raise, turn the kerosene heater off and remove the metal guard once cooled. Take off the wick adjuster knob, and employ the safety shutoff. Put the heater back together, and test the wick adjustment knob.