NWH, In my van the pole hose doesnt freeze at all for some reason, just all the tricolfex and ends of the microbore. When I'm out working its those y pieces that freeze and I do the same thing just blow throught them. I have never had my tanks water freeze even on days when I dont work and dont put the heater in but my friend who uses wfp in his transit always gets a frozen tank. Peoples van/systems seem to have different problems, Luke