I'm on my second winter with my homemade OWB and I insulated and installed my lines myself. I was really happy with it until about a week ago.
On installation, I used two lines of 1" oxygen barrier pex tubing, and slid lengths of unsplit, closed cell foam sleeves over each. I taped each joint in the foam, and taped the two lengths of pex together. Next, I put three wraps minimum of HVAC bubble wrap insulation over that. None of this will absorb water. Next I burried a 6 inch corrigated culvert from the stove to my house, with sand all around the pipe, and covered it with 2" high density foamboard insulation before I filled the ditch in with dirt. The ditch was 38" at the stove, and to get under my house, I brought it up to 28" as I passed under the foundation. I slid all my lines inside this pipe. I really thougth I had this one whipped.
About a week ago, I noticed in all the cold and snow, that the line from the house to the woodburner had less snow on it. As the days progressed, that part of the yard melted first. I'm not sure what could have caused this. I thought maybe one of my heater lines was leaking, but there is no obvious leak, and I HAVE ADDED NO WATER since I fired this thing up in October. (Thanks to everyone that helped out last year with my "steaming" issues.) I checked the water today, and it isn't down even a quarter inch. It is performing the best that is ever has. I will never be without a OWB.
Any ideas on the snow melt?? I will be pulling the lines out this summer to take a look. My guess is that maybe the corrigated drain pipe I ran my lines in has a leak, and the water has filled the pipe, and it will transfer heat, when the air space would not.
Ideas anyone??