Furnace Won't Start After Running Out Of Oil. If the furnace’s burner doesn’t turn on after bleeding the oil the first time, try again. The most common heating oil tank measures 275 gallons (although it only safely holds around 240 gallons).
Some really old furnaces won’t have a switch. It’s always when winter seems to be at it’s coldest. However, if your furnace isn’t firing until you’ve done it numerous times, then you’ve got worn out parts and you need to call someone in to look at it.