I do not think it will do anything to prevent gelling but it might keep the fuel in the bowl warm enough so water that is frozen in the fuel will melt and separate without plugging the filter.Ted,
I have heard, that if you have a good glow plug system, it will do good without it. A new heater is over a hundred bucks when I checked. I disconected mine last fall the first time it went below 50. Never missed it in our frigid Texas winters. Like I said, if your glow plug system is working good, and you are running good winter blend, I think you will be fine. IIRC, the fuel bowl heater helps with gelling.