After reading Roger Caffin's series on how well canister stoves can work in the winter I thought I'd try it out. This past weekend a friend and I headed to Canaan Valley in WV to do a 3 day backpacking trip. I bought a MSR Windpro and a new Coleman Cannister cartrige (70% butane/ 30% propane), First night was mid/upper 20s and I rigged the cannister for liquid feed (attached some legs to the cannister so it would be upside down), and proceeded to heat some water for supper. It worked well. I left the stove together for the night and the temps dropped to @ 10 degrees. For breakfast, I light it up and it working great, for the 1st pot of water (pot is the infoamous Wal-Mart Grease Pot). I also needed to melt some snow to have water for the day so I leave the stove on and proceed to melt another potful of water. By now the stove is definitely slowing down. I open the valve a bit to get more flame. I get enough water to fill my 1st bottle with water and proceeded to try to melt enough snow for 1 more bottle of water. By the end there was barely a flame with the valve wide open. I checked the cartridge and there was plenty of fuel left. Once I got home I checked the stove with the same canister and it worked great. Is there a minimum temperature that this setup will work at? I checked Roger's article and I couldn't find a minimum temperature rating, just that it will work in "really cold" weather. Anybody have an idea what happened or have a similar experience? Thanks!
Mark