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[shepherd boy]

Could someone verify my calculation; If I'm pumping 10 gpm and have 6 degree heat loss in no load round trip, 150 heating days per year.  38,000,000 btu loss or about 1.5 cords wood. Anywhere close?

[BoilerHouse]

A member once did a calculation using Logstar's heat loss figures and assuming a 100 ft run from boiler to house.  If I remember, Logstar had a published heat loss of one degree per hundred feet. He figured that this theoretical system would lose one cord of wood to the ground.    So, it is a big source of heat loss at the best of times. 
In your case, when I do the calc's, I am getting 3 cords heat loss and that is assuming a boiler that is 100% efficient.  Factor in boiler efficiency of 50%, and the heat loss in firewood is scary.
 
Assuming 1 btu/lb/F
Then 10 gal/min x 8.33 lb/gal x 1Btu/lb/F x 6F x 60min/hr x 24hr/day x 150 day/heating season= A really big number!!

So either all the snow has melted over your lines and the grass is green OR your temp difference is less than you think.  I have used those infrared thermometers and they can be notoriously inaccurate.  I have Ashcroft industrial thermometers on my system, and even they have an accuracy of plus or minus 3% so a difference of several degrees can be attributed to incorrect measuring devices.
Are you suspecting an issue with your lines?

[shepherd boy]

I don't have a good number on my heat loss. Just trying to get a
some thought on economics trying to get the ultimate efficiency from an outdoor furnace. When is there more spent than is feasible to get a reasonable return. Like I have heard a number of people say they use half the wood with a gasification unit but spend just as long preparing wood and then need to store and dry it. Like I don't have a wood shed and anything goes in the 24" door doesn't get split. too much free scrap wood laying around.  Same with underground lines, worth spending a lot on underground piping if there's not enough return.

[BoilerHouse]

I have the cheap 3 wrap pipes, and burn about 7 cords annually and I figure I am losing between 1 1/2 to 2 cords to the ground, but that is with 250 ft total underground distance.  So this compares with Logstar's numbers.  But the biggest difference is the outer layer - Logstar has a tough thick skin and I have the flimsy corrugate.   Mine will develop a leak some day, the underground heat loss and wood consumption will skyrocket, and then it will be time to dig it up and do it again.  So better to buy once and cry once.

If your wood is basically free, the labor to feed the stove is not great, and it gets the job done by heating your house, then that is the best system to own. 

[shepherd boy]

Same deal, wrapped pipe 125',been there for about 15 yrs, 15 more and ill let someone else worry about it.

 Just remember the days about12-15 years ago, you could buy a furnace and install kit for under $5000. Hardy , Taylor. Pacific Western, Lynx and more. People would put them downwind from their house about 30' away and run homemade or just pex inside a piece of corrugated pipe and thought they had awesome heat.  Now it's become a rich mans show piece. To me it's about saving money , not see'n how much i can spend just for braggin' rights.

 Now when it comes to fishing, that's a different story. yeah I got a pretty nice building for my bass boat. And it ain't saving me money. So I guess a man can put his money where he wants to. I think I'll go fishing.

[mlappin]

Its highly unlikely your moving 10gpm, more likely 7-8 gpm

[shepherd boy]

 I'd agree, just kinda pulled that number hypothetically to do a calculation.  I am happy with my system what ever the numbers are. It's been cold for us, down to about +5 , and forecast is for more of the same but can handily get 24 hrs. burn.

[hoardac]

I replaced my cheap wrapped pipe years ago. It was noticeable and paid for itself by the second year.