# Thermopex heat loss?



## Johnbull (Jun 18, 2008)

Have purchased a new E-Classic 2300 Central Boiler and awaiting delivery. I'm looking at 2 locations, one less convenient but closer to our home and would require site preparation, slab and wood storage area. The second location is 130' from my home and 150' from a detached 3 car garage and has an existing woodshed with a drive-in/drive-out front and side. I was thinking of placing the furnace on a pad just outside the shed but it could be fed from inside the building. My wood supply would be located there as well. Would two (2) runs of Thermopex at 3 foot depth with the one 130' and the second at 150' create a heat loss issue? The cost is rather exhorbitant but I am willing to pay the extra for the location assuming the heat loss is negligible.


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## whodoctor (Aug 6, 2008)

Enter the following into a Google Search Engine.  "Thermopex + heat loss"  and click on the link that says [pdf] Thermopex Install

This pdf document says that the heat loss is less than 1 degree F per 100 feet of thermopex.

I hope this helps.


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## JLPELL (Aug 9, 2008)

I have installed the thermopex for my boiler. Its about 90 feet from my house and the shallowest depth is about 4 feet in the ground due to extremely large rocks.  According to the temp gauges at each end there is no heat loss.  Seems to be a pretty good product.  The cost was about  $ 13.00 a foot.  Hope this helps.


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## JMann (Aug 9, 2008)

Thanks for the info.  I'm looking into ways to install underground lines from my garage to the house (approx. 50ft).  I was going to dig a 4ft trench, install my pex lines into a 4in corrugated pipe and have a local insulation company spray foam insulation into the ditch.  This may save a few bucks but may not be the best way to get after it since there is higher chance of user error.  The last thing that I need is to be digging these lines back up for repair.  I noticed that on the PDF link that Whodoctor mentioned, it states that you can bury the pipe 1ft deep.  Is that the case?  It would be great to not have to go below the frost line.


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## deccybaby (Aug 9, 2008)

Hi Johnbull,
I have two thermopex runs, one to my house (5000 square feet) at 120' away and one to a 3000 square foot fully insulated barn 300' away.  I buried all of my pex around 20 inches in the ground.  It is not frost you have to worry about, it is any ground water.  The 300' run has a 3 degree F loss on the other end so a total of 6 degrees F for the round trip with no heat load.  These numbers rang true all last winter even when it was -10F.  I dug my trench 30" deep, put  10 to 12" of sand as a base, installed the pipe, filled with sand level to the top of pex, then I put 2" rigid blue insulation on top (just 12" strips), and more sand with warning tape close to the surface for future reference.  It is incredible stuff but it has to be in a dry ditch.  Take a little time and you'll never regret the few extra steps.

I have also found that the closer the return temps are to the supply temps then the better it works.  All of this setup was for a CB6048 but have switched over to a Seton W130 after a few conversations with Fred himself.   

Happy digging,

Deccybaby


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## whodoctor (Aug 9, 2008)

I buried my thermopex 1 foot deep and have minimal heat loss so far.  I have seen that stuff run OVER the ground for a Winter installation.  You could simply get corrugated pipe and have a company spray insulation directly into the corrugated pipe for insulation.  I paid $13 a foot for my Thermopex pipe, and ended up with 14 feet of scrap...OUCH.  Still, I see it as a one time expense.  My entire system (E-Classic, Thermopex, interior connections, and 16' x 30' foundation for a wood shed, the wood shed, and partial enclosure for the wood furnace) will pay for itself in 2.5 years at todays oil prices.  To me, that's priceless.  Especially considering that my income fluctuates seasonally, with Winter being my slower season.  No more stress for me int he winter.  Amen.


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## Johnbull (Aug 9, 2008)

Thanks for the insights from everyone. Still awaiting delivery of a CB E-2300.

I am planning on going 3' deep and am stongly considering a bedding of sand with a good layer on top. Has anyone installed the Thermapex inside a solid corrugated 6' or larger rolled plastic pipe? Thought of doing this as additional puncture protection and isolation from ground water. Would the additional air space between the 2 add any insulating factor?

Johnbull
Central PA


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## whodoctor (Aug 10, 2008)

While I am always a fan of making anything as good as it can be, the CB E-2300 is supposed to generate a LOT of heat.  It replaces up to 800 gallons of oil a month if the dealer stats can be trusted.  I would certainly make certain that it doesn't get punctured or crushed, yes, but don't worry about the heat loss from the Thermopex.  That stuff is awesome.  I just installed mine two days ago, and it looks like 1 loading of the firebox is going to handle my hot water for about a week (I am not adding any more wood until I HAVE to because I want to see what the summer fuel needs will be).  My Thermopex is about 100 feet long, buried 1 foot in the earth, and I have no noticeable heat loss over that 100 foot run.  In fact it is a couple of degrees hotter once it get to the house.  This is likely a discrepancy in the temp gauges somewhere, but still, no worries.

Also, today is the 2nd full day with the E-2300 running.  I went out there to today to 'relight' the stove because I thought it had gone out.  It turns out that the 'smoke' from the stack is SO CLEAR that I couldn't even see it until I was right under it.  And at that point I had to really really STARE so see SOMETHING. The stove was still lit and running like a charm.  Prepare to be impressed.  I DID have to set the stove to get a 45 second pulse of air every 5 minutes, to keep it going, but it takes 2 minutes to set the program, and then the control panel takes care of the rest.  I have the dual fuel model, but I have not hooked up the gas.


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## kenkressin (Aug 11, 2008)

A very interesting post on a trench using pink sheet foam.  Nice technical discussion too.  BuildItSolar.com:
http://www.builditsolar.com/Projects/SpaceHeating/SolarShed/trench.htm

To me, expressing heat loss in degrees by itself is meaningless, since it neglects to consider the amount of water losing that temperature.  A better expression would be BTU/hour for each 100 feet.  If the flow rate is 5 gpm, that calculates 5 gpm*8 lbs/g * 60min/hr = 2400 btu/hr.  And remember, that is losing heat when the system is cycling (the water in the pipe is cooling, even if not moving).  Suppose a cycling system averages 50,000 BTU/hr, then that is 2,400/50,000 = 4.8% inefficiency due to the pipe - not negligible - if my math is right.


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