Is there a trick to?

Hey everybody.  Is there a trick to using an entire bottle of propane?  I've been hanging out in the Pod from time to time in the coldest of weather and have been using my furnace.  Well, when I get to about half a propane bottle, my furnace won't light on a cold start.  It seems to me that the furnace needs a bit more propane flowing to the furnace for the furnace to light on the start.  I've had this happen to me while camping as well where I have no problem lighting the stove and the hot water heater, but the furnace has a problem lighting.  Is there a trick to this.  Maybe opening the propane valve slowly on the start?  Everything else is great with the pod, but I just had to ask the rest of you if you too have had similar issues with the furnace and what you did to overcome it.