If you feed a gravity style kerosene heater from the top of an oil tank and you have a dip tube to the bottom of the tank, Will the oil continue to flow if the unit doesn't run for several days. My thinking is that once the syphon has begun it will always be there unless you run out of oil. Am I correct? The old tank is a bottom feed and the heater works well but I would like to change it to double wall which would feed from the top. I just didn't want to start problems.