Question about Outdoor boilers

[Dana]

Central Boiler recommends the shallow bury depth in case you have ground water near the surface. Water will conduct heat out of the plumbing much quicker than frozen earth.

[woodmills1]

Yes, ground water in contact with the heat pipes would be a much larger problem.  My pipes are shallow, around 2 foot.  They have a 1 inch black foam insulation and then a styrofoam box around that.  The whole outside run was then encased in a 9 mil poly sock, one piece from cellar to stove, being careful not to perforated it during installation.  I also lined the trench with sawdust and then covered the pipes with sawdust to keep from puncturing the bag.  My company, Free Heat Machine, made a big deal about excluding water from contact with the pipes.  Waters ability to either hold or remove heat is amazing.  I can still see the look on my students faces when I boiled water in a plain dixie cup using a bunsen burner.

[Furby]

That's why dirt is such a poor insulation.

[OneWithWood]

Much to my horror I discovered that wrapping the pipes in plastic was a big mistake.  It just traps condensation, saturating the styrofoam 

[woodmills1]

my plastic is a one piece bag from back of stove to inside the house.

[Mtnjack]

Remember insulation only slows heat transfer, does not stop it,just have to start mowing before every one else.I heat with a taylor 165 feet from house and lose 10 to 20 degrees,180 to 160 not a problem. Just taped bbq meter to pipe in basement.House is plenty warm. Mtn Jack