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[Range91]

I obviously am losing heat to the ground how much is the question. If anyone has any insight on this it would be great appreciated. My temp gauge shows in losing around 2 degrees for 100ft pump on medium speed. 3wrap zsupply 3.5 to 4 ft down sand/gravel soil. The second pic is reference that is my septic tank.
Is it worth upgrading to log stor or similar pipe? Cost effective ? Thanks in advance for any helpful input

[shepherd boy]

I'll give you a reply, but someone may have a better idea. A cord of dry oak is supposed to have 24m btu in it.according to my calculation you are losing about 24000 btu a day. If your furnace is 60% efficient it would take 600 days to burn an extra cord of wood. Your pipe is going to cost you a grand.what is your wood worth?Do you burn your stove year round?200 burning days a year and $200 a cord take you 15 yrs to break even. Am I missing something?

Remember this is Christmas afternoon and my mind may be cloudy.

[RSI]

Does it melt snow all winter or only when the air temps are above 32 degrees?
You shouldn't be losing 2 degrees. Are you sure your gauges are that accurate?

[slimjim]

As far as snow melting, it does make a difference what the ground temp is, the warmer the ground, the easier to melt the snow but at 3-4 feet down and those pics, flat ground, obviously wet soil and poor drainage, it sure looks to me that you may have water infiltration into the casing of your pipe, was there any sign of water present when you buried the pipe?

[Range91]

Well can't say the accuracy of the gauge I believe it was +or - 2 degrees but I will try and verify. As far as drainage or water infiltration I don't see how. I have a foot of top soil, 6-10" orange sand and gravel after that. I am pretty sure I have a dry casing never have had water in my house out of that pipe I would assume at some point it would have to come out right?? Hit water around here bout 24-26ft with the shallow wells. Anyone have better brand of gauge I could try inferred is not accurate on pex or copper. I don't have ground show all the time but can see that there is always less snow where pipe is

[slimjim]

The water does not have to fill the pipe, it could simply fill a low spot in the ditch, then seep into the pipe and voila.
Look I have a kind of gross way to describe heat loss to potential customers that they understand without getting scientific!
Put 6 people in a pool or pond, evenly spaced apart, we have all been there, now one person pees in the pool, it doesn't take long before everybody knows it, that's one pint of pee in thousands of gallons of water.
Now use that same thought regarding a pint of water inside your pipe casing and up against your pipe, your water level in the ditch comes up to the pipe and transfers the heat into the underground water in the ditch, unless you have very good drainage out of your ditch you will be constantly warming all the water within the ground. The only way to stop this from happening for sure is a very strong outer casing and closed cell foam insulation!

[shepherd boy]

I have tried to duplicate my calculation on heat loss and am probably wrong so some else needs to get it right. I can tell you Slim is right on water being a big factor in heat loss. water inside pipe is really bad but water against pipe on outside is bad too if the the pipe is not well insulated. This is where logstor shines. However we use a lot of z-supply pipe and while there is some heat loss it doesn't take  much to melt snow when temps are close to freezing. I have seen 3- wrap pipe with snow laying on pipe at 15 degrees not melting on top of the ground yet buried will melt it at 25+. Any heat loss will slowly heat up the thermal area and show up when you get close to freezing temps. Your septic is doing the same with a lot cooler water. Your line looks very similar to mine. Is your return line going back to the stove losing or gaining temp? If you are losing temp going back as well you may have a bigger problem. If anything you should gain from heat transfer from the feed.

[BIG AL]

I posted on this topic last season. I had 3 wrap pipe and I thought should be good enough. I had it down 4-5 feet no water present when I buried it. First I started to see snow melt over the pipe and I was surprised. Then it got worse I was burning 12 hours worth of wood in 3 hours. If I'm going to heat that much water I might as well have a pool. Switched to logstor and problem solved. For me the expense was justified in that I couldn't cut enough wood to keep up with the loss.

[willieG]

if you were moving 5 gpm your heat loss be about 80 btu per min and that all adds up to about 115,200 per day (80per min x 60 min x 24 hours = btu lost per day) now I read some on said your stove is 60 percent efficient so your heat loss number is about 60 percent of 192,000 and it is an acceptable average of 8600 usable bty in a pound of wood so 192000 divided by 8600 is about 24 so you are burning at this time 24 pounds of wood per day to make up for the lost btu's  if you ran your stove from November 1 to about  the end of march that would be close to 150 days 150 days x 24 is about 3,600 pounds of wood

however if you are just starting to notice this melting it will likely get worse if the water continues to infiltrate your pipe and moves farther down the line and causes more heat loss (if this is your problem)

believe me, I have gone through it to the point I was burning at least 5 cords a year extra, I had a run of 250 feet and in the dead of winter I had a 3 foot wide green grass sidewalk from the house to the stove!

[slimjim]

WOW, I sure wish I had paid more attention in math class in high school, Thanks WillieG, it's only 4 AM and you already have my brain hurting, I need another instant coffee with some maple syrup to get it moving in the right direction!

[Range91]

Thanks for all the replies I am going to gather somedata and will update when I do so. Seems that this only happens once wade weather hits. I also do not burn a lot of wood I can throw in 3-4 logs 20-22" long 10-12" diameter 25-30 degrees outside air temp and go 12hrs no problem. Heating dhw and 3800 sqft home with 18ft ceilings in living dining area. Just floored when I had seen grass the same shape as my line and so many good reviews about z-supply pipe. Again appreciate all of the feed back

[RSI]

If you want to see how much it is loosing, you could put a bypass at each end. If you bypass the pipe completely and watch how long it takes for the temp in the stove to drop, then bypass inside the house and compare you could calculate it fairly close. It wouldn't be real exact unless you were to empty the firebox once it is up to temp each time and do on similar outdoor temps.

[shepherd boy]

Now that would tell you for sure, some trouble but no more guess work.  Just a bypass in the house should give you a feel how much heat is being lost.

[BoilerHouse]

All underground pipe will loose a small amount of heat to the surroundings, even the good stuff.  Temp. readings can be inaccurate.  My industrial quality temp. gauges have a stated accuracy of plus/minus 3%. That equals 5 degree at 180.  I have cheap 3 wrap buried 4 feet down, and show heat loss by way of snow melt early in the heating season when the outside temp is at or just below freezing.  My main indicator will be wood consumption.  For 7 seasons I have burnt 6 to 7 cords a year, and somewhere between 10 to 15 pc's of wood a day. As long as that remains consistent, I figure I am good to go.

[mlappin]

All underground pipe will loose a small amount of heat to the surroundings, even the good stuff.  Temp. readings can be inaccurate.  My industrial quality temp. gauges have a stated accuracy of plus/minus 3%. That equals 5 degree at 180.  I have cheap 3 wrap buried 4 feet down, and show heat loss by way of snow melt early in the heating season when the outside temp is at or just below freezing.  My main indicator will be wood consumption.  For 7 seasons I have burnt 6 to 7 cords a year, and somewhere between 10 to 15 pc's of wood a day. As long as that remains consistent, I figure I am good to go.

Yah, I was kinda disappointed in my Honeywell gauges, not sure what the accuracy is, but I did have to rearrange them downstairs, if not the water returning to the stove would be warmer than it came in according to the gauges.