# Underground lines - not the place to skimp!



## Gooserider

This is a sticky inspired by Tenman, who suggested it as a topic to address one of the most critical components in a boiler system, namely the underground line set for those installations where the boiler and / or storage is in a different building from where the heat load is.

Not all installs use underground lines, and it is this moderators opinion that if it is practical, one is better off designing a system to avoid them, however this is often not possible.

However, it is worth noting that if an underground lineset is used, it will probably be one of the most expensive parts of the entire installation, sometimes costing even more than the boiler itself.  It certainly is the most difficult and expensive part to have to redo if one doesn't get it "right" the first time around.

It can also be a critical part to determining the performance of an entire system, with bad design choices causing poor system performance, high operating costs, and excessive wood consumption....

If one goes through the threads here in the boiler room, I would say that after the standard causes for performance issues such as bad weather sealing, and less than ideally seasoned wood, bad line set design is one of our more common issues, and one of the harder issues to fix.

*This is NOT the place to try and save money by going cheap on the design!*

So how does one do it right?

1. Make it big enough - there is an often linked to Taco paper on sizing pumps and other system components, including the lines.   http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf Before doing any other planning, figure out the heat loads, and determine the size of the piping needed, per the formulas in this paper.  In case of doubt, go bigger.  

Lines that are to small will cause problems of not delivering enough heat on cold days, or doing so only by using excessively large and power-hungry pumps (which can have their own problems, particularly on open systems) 

OTOH, there are relatively few problems caused by oversized lines.

Note that large sizes of PEX can be hard to find, and even worse to get fittings for, not to mention the high costs of the tooling needed for the very few connections one will need to make - it can sometimes be advantageous to do multiple parallel runs of a smaller size PEX, something that works especially well if using the "Foam in Place" insulation method described below.

2. KEEP IT DRY - one of the common failure modes for lines is to have ground water infiltrate the insulation system.  A system that may work perfectly when dry can become nearly worthless if it becomes compromised by moisture, as damp insulation becomes a good thermal conductor, and once wet drying an underground line is nearly impossible.  Pay attention to drainage in the trenches, with plenty of gravel and so forth to keep the water away from the lines.  Even more important, choose insulation materials that are in themselves waterproof - we see lots of horror stories about lines that are wrapped in bubble wrap and stuffed into a drain pipe, especially after they have been in service for a few years.  OTOH, there are several very successful installs with closed cell spray in place foam installed in a properly prepared trench.

3. Keep the runs short - saves money, and the less time underground, the lower the temperature drop that even the best lines will experience....

4. Insulate it adequately - Even a one or two degree no-load temperature drop going through the lineset can add up to a suprisingly large amount of heat loss over the course of a heating season, possibly as much as several added cords of wood worth....

5. Include some "support" lines - I always urge that unless you have already included other provisions for it, that you include a few runs of 3/4"conduit for electrical power and / or computer data lines (remember you can't put low voltage stuff like data lines, and AC power in the same conduit)  Those extra runs cost almost nothing to add when the trench is open, but can be a problem to add later...

Gooserider


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## taxidermist

This project was done by Larry (aka Tennman ) from this site. I just added the pictures. Any questions please ask Tennman.


First I want to thank Rob (Taxidermist) for posting these pics up for me...again. Aside from a few minor additions to the process I incorporated, this is the method discussed and presented here by Heaterman and others in the Boiler Room. If you search on Heaterman’s recorded data from a system install in the Fall of ’08 the heat loss for this method is remarkable. So I want to acknowledge those who were the inspiration for what follows. 

This post documents our second approach to what I believe can become the most critical component of the boiler system if you have a long run like ours. If done poorly it can be the greatest loss of efficiency in the whole system, trust me I know.

What follows is the objectives and method for our second method of insulating our 1 ¼” hePEX. My first underground approach was hastily done because November ‘09 was near at hand and I wanted to move on to the IMPORTANT stuff, install the boiler, and try to save money (bad set of priorities). If I say this once I’ll say it a thousand times, the potential energy loss from this component of the system poorly done will dwarf all the gee whiz stuff we do with controllers, the latest boiler technology, etc. AND this is compounded by a relatively long run. Our home is a historic dwelling so I was committed to having the boiler barn appear at home with our other outbuildings in vicinity of the house which resulted in a 170 foot underground run.

Goals:
1) Use CLOSED cell polyurethane foam to prevent water contact with the Pex.
2) Provide at minimum 3” all around each line with 2”-3” insulated spacing between the lines.
3) Protect the foam as best possible from being contaminated as a result of the foam blowing gun. Even if the foam is closed cell, voids with dirt clods and trash will hurt the insulation properties. 
4) Completely enclose the lines, void free to prevent water contact with the Pex and water migration down the lines into our root cellar.

Method:
1) I used a trencher for the first attempt which made about a 6” wide trench. To prevent damage to the expensive 1 1/4” Pex we used a mini-backhoe to dig up/recover the Pex and make the trench you see here. This resulted in a trench about 12” wide which I really didn’t want (extra foam, more cost) but actually worked well allowing us to work in the trench as you can see.
2) After extracting the homebrew insulated approach, we leveled the bottom of trench and laid the plastic. 4 mil worked well, thinner would have blown around too much and thicker would have been too stiff. This is very cheap protection to prevent contamination from trash getting in the foam.
3) Hooked up the Pex lines at BOTH ends. My Pex fittings were already on so if we had foamed the lines with them shifted even several inches I’d been screwed and would have needed to add another joint. Once foamed obviously the Pex will no longer move.
4) Neither the foam contractor or I had ever done this before so after the foam equipment was out and ready we had a team meeting to discuss what we were going to do and how. This team meeting is very important to get everyone on the same page from the beginning.
5) We decided on a 3-man team: 1- the foam gun guy, 2- the guy managing the Pex spacing close to the foaming process, and 3- the guy keeping the Pex suspended so the foam guy can spray onto the plastic under the Pex lines and then lower the Pex at the right time into the expanding foam underneath.
6) We started by filling the access conduit where the Pex lines go thru the slab into the boiler barn. We started at the barn and worked towards the house. Guess I figured that if we were going to screw up while learning I wanted that to be out at the barn.
7) The Pex lifter (me) held up the Pex so the foamer sprayed foam on the plastic under the Pex. As the foam expanded to about 3” underneath I lowered the Pex line while the spacing guy held them apart then the foamer just sprayed on top making sure there were no voids as the foam expanded around the Pex.
8) Repeated this process in roughly 2’ sections working continuously and literally within 10’-20’ we were cooking as a team. It took us about 30 minutes to do 170’. We were walking on the foam immediately when done. The heavy mini-backhoe drove over the stuff repeatedly leveling and replacing the dirt back within an hour of spraying.

As a result of all this our Wirsbo-Uponor oxygen barrier hePEX is encased in a solid block of foam about 10” wide x 7”-8” deep. It was easy and cost competitive with the commercial pre-insulated stuff. Lord willin’ I never see this part of my system the rest of my life. Come December ‘10 I’ll be able to give the delta T’s from four sensors (two at the boiler and two at the HX). 

Costs:

Uponor Wirsbo 1 ¼” hePEX = about $2.80/ft (not including shipping)

My cost to foam = $4.70/ft (this will vary based on contractor)

Total $/ft = $7.50 (does not include dirtwork, etc.)



Had I done this initially we would have saved between $1,500-$2,000 because of the re-do expenses and would have been able to focus on other “first season” issues. Hope this is helpful to those that come after me.


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## wood thing

IVE DECIDED TO REPLACE THE LINE SETS FROM THE BOILER BUILDING TO THE HOUSE.  THE EXISTING LINES ARE 1 1/4" BLACK IRON PIPE SANDWICHED IN 2" BLUE BOARD.  IVE KNOWN FOR A LONG TIME THAT I HAD TOO MUCH LOSS AND SINCE I RETIRED THE AQUA THERM AND REPLACED IT WITH AN ECONOBURN & STORAGE,  ITS TIME.  I HAVE READ SOME COMMENTS HERE -- ALL GOOD.  THERE IS NO FOAMING CONTRACTORS NEAR BY.  I WOULD LIKE TO RE USE THE BLK IRON IF NOT PITTED.  IT MAY BE POSSIBLE TO DIG UNDER THE LINES WITH OUT UN HOOKING.  I HAVE ALSO THOUGHT ABOUT CUTTING THE LINES AND INSERTING THEM IN A CASING,  BUYING CANNED FOAM, BUT WONDER IF THIS WOULD BE ENOUGH INSULATION.   THANKS


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## foamit up

Wood Thing, You can find a sprayfoam contractor on www.sprayfoam.com .  I put my pipes in a 6 inch drain pipe then filled pipe with foam, then foamed the whole pipe outside with a couple inches around pipe. You have to use 2 or 3 pound foam, as that is the only foam that will not take on water. Most can foam does not meet this spec. You can get some DIY foam that works. You have to line trench with foam to keep dirty out. I loose no degrees off my water temp in 100 ft of pipe. Spray foam keeps the warmth at home. Foamit Up


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## shagy

taxidermist what was the cost per ft. Im glad to see  that you wrapped your lines with plastic. I have dug up a number of lines that were sprayed with a foam that were "water proof" Gooserider said it all.So many out there are in for a rude awaking.


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## Tennman

Sorry guys. I haven't been checking this sticky. Taxi posted my process above but it's up to be to provide the details. First off I need to talk to Goose or someone to figger out how to edit the above post to correct an error. The cost/ft of the pex needs to double for two lines. I was just in a hurry to type it up and didn' think. I want to reemphasize that there are TWO types of foam CLOSED CELL and OPEN CELL. Both have a purpose in life. There are applications where you want to foam to breathe and "leak". For example, sprayed on the inside of a metal roof you want OPEN CELL so if you get a leak you'll know and fix it. We want CLOSED CELL for our application which is water impervious. The spraying contractor must be told what you want.


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## CORVAIRWILD

I was thinking to do the same thing with my future Waste Oil Boiler. It would run under a large driveway and truck turnaround, so it'll be placed in 8 or 10" corrugated sewer pipe. I wonder if plastic would still be needed?


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## Tennman

I presume you intend to insert non-insulated pex into the corregated pipe then blow foam around the corregated pipe. Better than nothing but less than ideal. The pex will radiate into the cavity and the return line will inevitiably absorb energy from the supply line. Making the sewer pipe cavity nice and cozy will cost you energy you want to dump into your home. This is assuming I understand what you intend to do. I'd still do the plastic since it doesn't cost but maybe $20 and makes whole process cleaner. But if the trucks will be driving on the foam, why the use of the corregated pipe? Unless the foam was quite deep I might worry about crushing the foam long term. If it was a high traffic area with heavy trucks, I'd be concerned of eventually of damage to the foam, not the pex. Others here like Heaterman may have experience with long term durability of the foam in a high vehicle traffic environment. I'd PM Heaterman and ask how deep you need to be for the traffic loads to pass into the trench and not into the foam. Basically anything you warm between the boiler and the HX is a waste of hard earned wood BTUs.


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## CORVAIRWILD

I thought my idea was good, the corrugated to hold the ground up, it's a driveway, not a road. The one supplier I looked at was just an inch or so of foam, and I would use 3-4", so wouldn't that be better??? My foam would be INSIDE the 8" or 10" corrugated, and I would hold the pipes up with wood blocks with holes for the PEX to keep it centered. The pix are 4" blue corrugated, $15 a foot


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## Tennman

Ahhhh..... Foam INSIDE the 8"-10", yes that will be excellent provided you are successful at achieving one key and difficult operation. My First Failed Attempt (futhermore referred to here as the FFA) used 6" dia x 8' ft long corregated pipe sections and I covered my 1 1/4" pex with the standard split foam insulation sleeves. Unbelieveably tedious to install sleeves on both pex lines, duct tape together, slide a section of corregated pipe, snap together, repeat many times for ~170' THEN come back and drill lots of holes in the corregated pipe and inject closed cell polyurethane Tiger Foam. All together probably cost me $7-$8/ft (BIG savings huh.....totally wasted). For all the world to see here, this is why it failed. Because the two lines with sleeves fit so tightly inside the 6" when I injected the foam it could not expand completely around the sleeve and pex bundle. I had filled most of the cavity with the sleeves AND I saw the foam coming out all the millions of pin holes in the sewer pipe (should have been my first warning). My helpers were already tired of the whole job and the foam was not encapsuating everything as envisioned so I soon saw injecting the foam as a waste of time. Turns out those sleeves acted just like sponges when water seeped thru the corregated pipe. The tiny good news was that some of the water surely drained thru the pin holes in the bottom, but the sleeves stayed water soaked. When I dug up this disaster last spring all of the INSIDE of the corregated pipe was covered with MUD! I type this not just for you but the thousands who will read this sticky after us. IT IS VERY DIFFICULT FOR US DIY's to INJECT AND GUARANTEE COMPLETE 360 deg ENCAPSULATION OF THE PEX LINES WHILE MAINTAINING PEX SEPARATION. For this reason and based on my experience, if you really want to use the corregated pipe, I would do the foam injection out of the trench up on sawhorses so I could inject into TWO holes AT LEAST 180 deg apart. The large dia will give the foam more time to expand and having a hole on the other side you will see if it is expanding. But I'd inject on both sides just to be sure. I can't emphasize this enough, IF YOU GET WATER CONTACT ON THE PEX.... YOU'RE SCREWED!

Now if I were you and I had just gone thru the what I had, I'd forget the corregated pipe, dig the trench maybe a foot deeper and foam in trench just like I did. Making the trench deeper allows more surface on the side of the trench for the vehicle loads to "shear" into the ground (distribute the loads into the surrounding ground). Just going a little deeper will protect the foam and assure you get that critical pex encapsulation for far less work. Or if you're still nervous lay something on top of your foam in trench before you refill with dirt. There will be some voids but soon, in time, those voids will fill with dirt. My 2 cents. Getting good encapsulation in that corregated pipe while keeping the tubes separated and centered is far more difficult to achieve than digging deeper or placing a load bearing surface on top of the foam. We can only hope someone will reply here with a trench depth over a high vehicle traffic area that worked. Mine was a little over 2' and the backhoe ran over it repeatedly. I can also report that this season's performance is unbelievable compare to last with our new insulated line. I'll post later with hard data.

Ok... I typed this for posterity Corvairwild. I was excited because I first read your handle as Corsairwild. But got it, you're a car, not airplane guy. Best Wishes to you and all who come after. So here's my warning, "Those who ignore the lessons of history are doomed to repeat them."


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## CORVAIRWILD

Hi TENNMAN... I read your post to my wife, and so much fer the corrugated idea... 

I just had a 1" water line installed in a 5' deep trench last month, so it's fresh in my mind, and I WAS thinking that sometimes what seems like a brilliant idea, until you try actually do it!

The area between the whse and house is a turnaround for the driveway, so the traffic will be minimal, and I'm not anxious to spend the extra on corrugated sewer pipe. Unlike the rolls of 4 or 6", the larger size is far thicker, and two layered, or double walled. I bought some damaged sewer pipe last year, but forget the price.

Maybe I should use the factory installed insulated underground pipe I pictured above, but find either as thicker insulated version, and line the trench with low quality 2x wood, and foam it, all wrapped in thick plastic... 

My concern was the exorbitant price of the above piping, and the seemingly small amount of insulation. I just can't believe that 1" or so of white foam is really an effective amount of insulation. We're talking 180f water in 50f earth.

There must be some heat loss specs fer the piping???


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## Tennman

If I was to purchase a pre-insulated pex product it would be one of the polyurethane injected/molded products. I can confidently say there is no way to get better energy transfer at a lower cost than the foaming in the trench process. There just is no way to practically manufacture a two-line insulated pex product that is about 14" of solid closed cell polyurethane in cross section like can be done in the trench. We used a minibackhoe with a bucket that dug a trench about 12"-14" wide. So our pex has 3" spacing AND about 4" all around which was the result of filling the trench width with foam. If you are just talking personal vehicles, not heavy commercial trucks driving on the buried lines, then I wouldn't be concerned about driving over it routinely if it was 2'-3' down. Whatever you do... DO NOT worry about saving $500 on this part of the system. The underground done poorly will translate into you spending hundreds of more hours in the woods cutting, moving, splitting, and stacking because of lost efficiency. I'm reluctant to present our temperature loss data yet. It's so good I don't believe it yet. Great pics by the way.


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## rkusek

The bottom line on all this either foam it in trench with sprayed closed cell insulation or use the Thermopex product.  If you think you can make something yourself a little cheaper be prepared to dig it up and redo it the next year.  A little bit of failure makes the whole thing useless.  Like the headline says "NOT THE PLACE TO SKIMP"!!


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## CORVAIRWILD

Ok, OK I won't skimp. I just didn't like the only product I looked at locally. Their blue stuff above, and $15 a foot. they're nukin futz

I was thinking to use a better product, and THEN foam the trench, which around here should be 5' deep, due to the extreme cold. I would def use anti-freeze in the lines, but still feel I should go below the frost line, 4 feet. 

BTW, the pix, (from TL, CW) are a solid wood horse I bought my wife as a wedding present 18 years ago for $125, with our then stray kitten on the back.

My wife, our Lab/Beagle we just put to sleep this summer, 14 years old, and our found Pekingese _Freekazoid_ Mugs, on Lake Champlain, near Burlington Vt

Mugs and me at a Marina on Shelburne Bay Vt a few minutes before they asked us to SCAT! Here's the vid I made of that moment... (Couldn't find that moment, but here's the recreation path immed adjacent to the marina...

http://www.youtube.com/watch?v=1YQqG346gss

http://www.youtube.com/watch?v=OhRe0TQCl7Q

And Mugs and his (late) best buddy, Lady Bug...


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## juddspaintballs

Here's an idea:

Dig a 2' wide trench 4' deep or so.  Lay down sheet plastic on the bottom of the trench.  Put one level of cinder block along both sides of the trench the entire length of it with the open sides facing up/down.  Spray foam plain old OB PEX in between the cinder blocks.  A 24" wide trench with 8" block on either side will leave you a 8x8" empty space between the block to run the lines and spray the foam.  That'll provide you extremely great insulation and the block will provide you support for vehicles driving over it.  Backfill and compact the dirt and you're done.  Never worry about it again.  Maybe drop a couple electrical conduits in the dirt before you back fill too.


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## CORVAIRWILD

Hmmmm....


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## Gooserider

I tend to agree with the posts suggesting that you just use plain PEX with foam in place, rather than any of the commercial pre-insulated products...  Seems to me that using a pre-insulated product plus foam in place won't gain you anything over straight PEX plus foam...  

I don't have solid numbers, but I have a very low opinion of the commercial products - I don't feel like they offer a good value at all - they are overpriced, and mostly come in pipe sizes that are usually smaller than the best choices from a flow volume / pump sizing standpoint (which means you get to pay more over time for the electricity to drive the overpowered pumps needed to get the BTU transfer rates needed.  This is on top of the less than stellar heat loss ratings that the products offer - IMHO there is a reason that they make it hard to find their heat loss numbers - if they were really good don't you think the manufacturers would be putting them on the front page of their advertising sheets???

Back when I could dream about a boiler, I would have preferred to go with a boiler in the house setup, but if I had to do an outhouse install, I certainly would have gone for a plain PEX / Foam in place line setup, and made whatever trench design I had to in order to accommodate it...

Gooserider


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## AOTO

Do not skimp on the pipe that goes in the dirt.  I can tell you that 20 cords a year to heat a house, barn and domestic water is not very fun at all.  I just moved my boiler to another house I bought and I paid $18 / foot for 1 1/4" pipe.   I skimped last time and was mislead by using the triple wrapped pipe and water must have gotten inside of it and that makes for a radiant path 150 feet long.  I lost 40 degrees each way, not including the load.  It doesn't matter what kind of boiler you are using, the pipe is the key.  Good luck.


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## CORVAIRWILD

Misled by the triple wrapped pipe?  Tell me more about the triple wrap pipe please... 

I wonder why the blue stove I pictured above looks so simple, and is so much $$$, and Catskill Boiler's insul PEX is $8 a foot, almost 1/2 price!

http://cgi.ebay.com/Outdoor-Wood-Bo...452?pt=LH_DefaultDomain_0&hash=item19b6500f14


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## rkusek

[quote author="CORVAIRWILD" date="1290851950"]Misled by the triple wrapped pipe?  Tell me more about the triple wrap pipe please... 

I wonder why the blue stove I pictured above looks so simple, and is so much $$$, and Catskill Boiler's insul PEX is $8 a foot, almost 1/2 price!

http://cgi.ebay.com/Outdoor-Wood-Bo...452?pt=LH_DefaultDomain_0&hash=item19b6500f14[/quote

Looks like the stuff that will lose 40 degrees into the ground.


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## CORVAIRWILD

The pictured pipe has the corrugated black plastic sewer pipe, just it doesn't appear in the ebay opening pix


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## juddspaintballs

I didn't get any pictures while doing the process, but I just finished my underground lines this morning.  I dug the trench with a mini excavator because I had a bunch of roots to go through.  At 6 AM this morning I laid down my 1" PVC electrical conduit and by 7 AM my new buddy arrived with the goods.  

I met this guy a couple weeks ago because we share a common interest - Military vehicles.  We both have a M35A2 (an old military 6x6 cargo truck commonly called a deuce and a half).  We chatted for a while and he noticed the trench I had dug.  I told him I was waiting until I had the cash to pay a spray foam contractor come foam my lines in place.  Well, he's the sort of guy who has worked just about every kind of job that you can work with your hands over the years.  He's done spray foam many times before on boiler lines and he's still got contacts with the supplier.  He talked to his supplier and his supplier had some spare tanks of foam lying around.  My new buddy got those tanks for free, as well as two brand new sets of tanks for free from him.  

We spent a couple hours this morning foaming my lines into place.  I used 1-1/4" PEX and 4 mil plastic sheeting to do it just like the original post of this thread.  We sprayed lifted it and sprayed as we went then finally wrapped the foam in the extra plastic after it set.  The temperature outside was 35 degrees when we started and it's still just as cold but it also got very windy.  Spray foam sets up fine as long as the tanks are warm as you spray since the two chemicals mixed make an exothermic reaction.  The tanks we used had a color coded thermometer on them to tell us when it got too cold to spray the foam.  We had to stop three times during the process.  Once because the partially used tanks ran out (and since they were old the foam didn't set up at all).  We removed the crappy foam and hooked up the first set of new tanks.  We sprayed until those ran out and then switched to the 2nd set of new tanks.  We had to stop mid-spraying with those tanks to let them re-warm in the house.  Including re-warming the tanks, it took us about 2 hours to lay the plastic in the trench, spray the lines in place, and then wrap the plastic around the top of the foam.  

FWIW, the new tanks he got were rated to spray about 200 board feet.  They actually covered about 60' of my 1-1/4" lines with 3" of foam including a large mass of foam filling in the hole I punched through my basement wall both inside and out.  I've still got a little more than half of the other tanks left over since my run was only 80'.  I suppose if you had a run up to about 150', the 600 board foot spray foam kit you can buy from TigerFoam should be sufficient if you want to spray your own lines in place to save a little cash.  

I could go get you pictures of my foam if you wanted, but it's all wrapped up in clear plastic.  Nothing special, nothing different than the pictures in the first post other than the scenery.  Including the price of the plastic sheeting, the PEX (with spare), and the electrical conduit my lines are in the ground for about $6.85 a foot 

It always helps to know people!!


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## AOTO

I included a picture of the stuff I used last time.  I actually used the double wrap.  I will tell you this, regardless of the "wrap", if there is a pin hole in that black drainage pipe, water will get in and you will be done. You will hate the day you put that crap in the ground. The black pipe I used had holes in it when we put it in the ground and I thought nothing of it. Pipe was on a 4 week back-order and I had to get it in the ground that day. I will never use that stuff again, ever.   You get what you pay for.  I bought three hundred feet of the double wrap @ $9.00 foot, when I could have paid $12.00 a foot 4 years ago for the decent stuff. Now I paid $18.00 / foot for this new material and frankly I don't care. Ig I can burn 6 or 8 cords, it'll be better than 20.  That really takes the pleasure out of using wood. This is the right stuff for my application.  If people can foam their own, then more power to ya.  The new pipe I laid in the ground will lose 0.5 degrees @ GPM running 100 foot.

http://www.urecon.com/documents/pdfs/brochures/Urecon_PEX-Flex.pdf


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## CORVAIRWILD

MHVFD, So what makes 1 underground pipe better than the other? More insulation? Any black corrugated can have a pinhole, or many!

juddspaintballs, what size are these foam can? like spray paint? or propane bottles?


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## juddspaintballs

The 600 board foot kits are the size of propane tanks.  The 200 board foot kits are about the size of a large bottle of bleach.


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## CORVAIRWILD

and where do we buy these? I don't need a faom contractor breathing down my back. I like to be independent


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## AOTO

The key word here is "infiltration". Like your house, it doesn't matter how much you insulate it, if cold air can find it's way in you won't be pleased with the loss of heat. Water infiltration on your pipe is the worst. The water will fill the drainage pipe and then soak the little wrapped cellulose/reflective material.  Now the hot water has to pass by all of this and the old saying of heat goes to cold is true. The water wants to become warm so it sucks the BTU right out of the pipe.  As I wrote earlier, I ran my line 150 feet from the boiler to the house and lost 40 degrees going in and another 40 going back, not even accounting for the load from the house or the hot water usage (Potable/Domestic).  The "Wrapped" pipe leaves plenty of air space around it, inside the drainage pipe. The micro cell foam looks like a spongy insulation and I don't know that much about it although I would say if water got in there, it might seep down to the pex lines.  The stuff I'm using (See below) is hard foam.  Even if I got a pinhole in the black outside piping, there is no where for the water to go. It would stay on the outside of the hot water lines.  
I don't know where you are located but you could contact the mfg to see if you can get some in you r neck of the woods. 

Urecon (Florida)
4185 South  U.S. Highway 1
Suite 102
Rockledge, Florida  32955

T: 321.638.2364
F: 321.638.2371
E: sales.usa@urecon.com


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## CORVAIRWILD

I'm on the Canadian border, so it's COLD! 20f yest... The pipe pictured is from Florida??? What do they know from heat? they do have a hi water table tho...

So it would seem that this's what you're using? where's you get it? a local supplier? Shipped especially for you? What's the heat loss? Price p ft?


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## AOTO

Canada      
Urecon (Quebec)*
1800 Ave. Bedard
St. Lazare-de-Vaudreuil, Quebec
J7T 2G4

T: 450.455.0961
F: 450.455.0350
E: urecon@urecon.com     Urecon (Alberta)*
5010 - 43rd. Avenue,
P.O. Box 210
Calmar, Alberta
T0C 0V0

T: 780.985.3636
F: 780.985.2466
E: sales.west@urecon.com
* manufacturing facility     * manufacturing facility
Urecon (Ontario)
115 George Street, Suite 625
Oakville, Ontario
L6J 0A2

T: 905.257.3797
F: 450.455.0350
E: sales.ont@urecon.com     Urecon (Quebec)*
48 rue Séguin
Rigaud, Quebec
J0P 1P0

T450) 451-6781
F450) 451-0132
E: fabrication@urecon.com
      * manufacturing facility (field applied insulation fabrication)
Urecon (Newfoundland)
3 Bluebell Bend
Portugal Cove / St. Philips, Newfoundland
A1M 2G5

T: 709.895.8100
F: 709.895-8101
E: sales.nfld@urecon.com


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## CORVAIRWILD

Kewl I'm in New York, the American side! But not far from above addys


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## AOTO

It's 19f here right now.  I'll get my heat exchanger hooked up Monday so I should be off oil(again) very soon.  Good luck with the project.


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## CORVAIRWILD

Maybe the best piping?

http://urecon.com/about/company_info.html


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## AOTO

I'm thinking this is the Cadillac of pipe.   You'll pay for it.  I bought mine in Hoosick NY.  I bought 1 1/4" ID for $18 / Foot.   The connectors are special order and will run you ~$62 / per connector.  Canada was going to ship them for $311 ( for 4), but I instead rammed an 5" x 1" black nipple pipe down it about 4 inches. I will know Monday how that works. Stay tuned.


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## CORVAIRWILD

I'm in Canada very often, was there twice this week, I have an apartment and business there. Canuks cross to the USA all the time fer the cheaper prices

Why not take videos of your job, I'll vid mine. Mrs is on the phone with the contractor rite now. He hunts on our land, and does good excavating for us

http://www.youtube.com/watch?v=xiyB7_fVTzs


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## rkusek

mhvfd said:
			
		

> The key word here is "infiltration". Like your house, it doesn't matter how much you insulate it, if cold air can find it's way in you won't be pleased with the loss of heat. Water infiltration on your pipe is the worst. The water will fill the drainage pipe and then soak the little wrapped cellulose/reflective material.  Now the hot water has to pass by all of this and the old saying of heat goes to cold is true. The water wants to become warm so it sucks the BTU right out of the pipe.  As I wrote earlier, I ran my line 150 feet from the boiler to the house and lost 40 degrees going in and another 40 going back, not even accounting for the load from the house or the hot water usage (Potable/Domestic).  The "Wrapped" pipe leaves plenty of air space around it, inside the drainage pipe. The micro cell foam looks like a spongy insulation and I don't know that much about it although I would say if water got in there, it might seep down to the pex lines.  The stuff I'm using (See below) is hard foam.  Even if I got a pinhole in the black outside piping, there is no where for the water to go. It would stay on the outside of the hot water lines.
> I don't know where you are located but you could contact the mfg to see if you can get some in you r neck of the woods.
> 
> Urecon (Florida)
> 4185 South  U.S. Highway 1
> Suite 102
> Rockledge, Florida  32955
> 
> T: 321.638.2364
> F: 321.638.2371
> E: sales.usa@urecon.com



This looks like good stuff kind of like Thermopex.  Much better than any of that wrapped tin foil stuff.  Probably $15 a foot but if you don't want to foam in trench this would be the way to go.


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## CORVAIRWILD

I wonder if they'd custom manufacture the 1 1/4" in a 6" corrugated? EXTRA FOAM


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## juddspaintballs

By the time you get it done, it'll be cheaper to foam in place.


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## shawntitan

Be careful with the "foil insulation wrapped pex in black corrugated pipe" like they sell on ebay, a buddy of mine just had to dig up his yard as his was leaking water in his basement a month after he installed it, probably some kind of manufacturing defect in the pipe is my guess... like the title of this thread says, not the place to skimp.


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## skfire

http://na.rehau.com/files/INSULPEX_Tech._Manual_10.03.pdf

I am looking into this stuff.(see link above)....heard some good things from local plumbers that dealt with it...any feedback?

Scott K


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## CORVAIRWILD

I hate PDF files Can they be transferred into anything more easily read???


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## skfire

Sorry, I  see no other format available.
Any one with experience on this product?
SK


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## AOTO

I just finished w/my install on Monday, using the Urecon "Logstor" pipe.  I'm running 90 feet of 1 1/4" ID from my Sequoyah E3400 to a 24" x 24" water to air exchanger.  I believe it's a 240,000 or 250,000 BTU exchanger.  
The temp on my boiler is set for 190f with a 5 degree low point for reactivation of the fan.  I'm using a Wilostar 30 which I think is running at ~9-10 GPM and it's pumping heated water 24/7 thru the exchanger. I have temp gauges on the exchanger and it appears I'm losing zero degrees on the supply side. When the Furnace fan kicks in, it looks like the delta is ~10-12 degrees, but it's hard to say since the gauges have a dial on them and I have no clue how accurate they are. I do know that with the other pipe (double wrapped) I used, the loss was incredible and I had a radiant path all winter to my wood shed.  Snow is expected today and for the next week so I should get a better feel for how the system is working.
I will tell you this, the wife isn't bitching about the house being cold as I've set the thermostat at 69f in the hall way downstairs. By the time it gets to the office upstairs, it quite a few degrees higher than 69f and she's very happy.  I'll update as the winter draws thru and bases on the wood I've used so far, I'm looking at burning 8-10 cords versus the 20 cords I had to cut and store.  Sounds like a better Xmas already.


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## AOTO

I added the rest of the pics....let me know if anybody has any questions, suggestions, etc.


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## SnowTraveler

When I relocated my gassifier from the house to the new boiler room in 2008, I used Insul-Seal pipe.  One of the super-posters here, a contractor I believe, stated he uses only this method and I followed his lead with no regrets.  I am flowing 400 feet round trip and have only 1 degree of heat loss, and that is a stretch, as I am using calibrated instrumentation and actually show less than a degree.  Very expensive up front cost, but well worth it for the long run.

http://www.insulseal.com/


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## stefan66

CORVAIRWILD said:
			
		

> I was thinking to do the same thing with my future Waste Oil Boiler. It would run under a large driveway and truck turnaround, so it'll be placed in 8 or 10" corrugated sewer pipe. I wonder if plastic would still be needed?



Just to let you know. I'm using 1'' pex with 1/2'' slip-cover insulation
wrapped with duct tape pushed through 3'' pvc plastic pipe.
Seems to lose about 2 deg. on a 90' run.


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## pwschiller

This foaming in place method seems like a great way to go, especially if you are planning on having multiple pairs of PEX lines. I have a couple questions about it though. I assume that you aren't relying on the polyethylene plastic sheeting to keep water out, but more to keep most of the dirt away from the foam and so that the foam can be wrapped up in a neater, more circular package as the foam is curing? My backhoe has a 24" bucket which is far too wide for doing the foam in place method without first narrowing the trench where the foam will go. Since I will also be installing multiple electrical conduits in the same trench, does it seem like a good idea to make a smaller trough to one side of my trench using 2" of XPS foam sheathing on the bottom and on two sides? XPS foam sheathing (R-5 per inch) costs about $0.44 per board foot, making it a slightly better value than the spray foam (R-7 and about $1.00 per board foot). I'm thinking that the XPS will butt up against one wall of the trench and then I will backfill over my electrical conduits with enough sand to hold the other XPS wall in place, maybe putting an occasional spreader between the two XPS walls to keep the sand from pushing the wall in prior to adding spray foam. I can still put the polyethylene sheeting under my XPS trough and wrap it over the top of the expanding spray foam. Does that all sound like a good plan in my case? If you were to do it this way, would you cap off the trough with 2" of XPS on top (with some temporary weights on top of the XPS) after spraying in the foam, or would you just let the spray foam expand out the top of the trough and wrap the plastic over it?


----------



## juddspaintballs

What I did was dig my trench about 4' deep with an excavater and then I ran my electrical conduit on the bottom of the trench.  On top of that, I draped my 8' wide plastic sheet in the trench like a deep 'U', securing the ends to the top of the trench temporarily.  That created a nice sized trough for the pex and foam.  I laid the pex in, then spray framed in place while lifting the foam as I went.  Once the foam was hard, I tucked the plastic around the foam and I backfired the next day.


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## rowerwet

I bought thermopex 12.50/ft for 2 1" pipes inside, I have 85' and can't find any heat loss for the run, manufacturer claims 1 degree loss for each 100'. I spent over 1 grand but that was money well spent.


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## Tennman

Pete, Yes, I used the plastic sheeting just to keep the process clean. After the foam is blown it serves no purpose. I just laid it up on the sides of the trench as shown in the pics and put rocks on it every 8-10'. Ok.... can't spend a lot of time on this but a quick look shows XPS thermal conductivity at .027-.03. Urethane foam at .021. Do some quick research on line like I just did and compare Heat Transfer Coefficient. Bottom line using the spray polyurethane is a better insulator so using the sheet stuff is a waste of time and money. No need for multiple trenches, since the electrical conduit doesn't care about temperature, you can do what I did, just lay on top of the cured foam and cover with dirt. So in summary, if you compare the material properties of what you intend to use, you'll most likely find the XPS is a poorer insulator (or a better heat transfer material) than the spray, closed cell, polyurethane. 

BTW, my water round trip distance is about 440'. I am routinely seeing a 2*F delta from my AZEL temp sensor in the boiler room where my water enters my 1 1/4" Pex. After prolonged idle... yeah bad but.... I frequently see the deltaT close to less than 1*F (an unbelievely sometime less than 1*F). That is an amazing .22*F/100' of run. In review, my contractor that dug up my first "go cheap" attempt using those insulation sleeves had a 12" wide bucket. So my pex is in a block about 12"W x 10"deep. Far more than most need but it was a byproduct of carefully digging up my first attempt so I could reuse my pex (mission accomplished). If I knew how I'd post pics of my AZEL digital display to so the temps to document what I'm asserting. There ain't no way the off the shelf stuff can match my 12"x10" foam brick that I had sprayed. My underground is about 180' and I paid $700 or $800 to do the trench. All insulation done in about 30-40 minutes then recovered with dirt. I would guess the cost/performance crossover point for spraying in place vs the Thermopex type stuff is maybe when the underground gets in the 30'-40' range. At shorter underground distances the losses using a Thermopex type product probably wouldn't justify the expense of a foam contractor's minimum charge.


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## pwschiller

Thanks Tennman. I didn't say that XPS was a better insulator than the spray foam, but that it was a better value from an insulating standpoint. 2" of XPS is R-10 and costs about $0.95 per square foot. To achieve an R-10 value with the spray foam you would need a layer about 1-7/16" thick, which would cost about $1.43 per square foot if you are using Tigerfoam. Maybe by hiring a spray foam contractor you can have it done for less than it would cost with Tigerfoam. In terms of labor, you are absolutely right that slinging plastic sheeting into a trench, secured on the sides with rocks (which I have plenty of here in NH) is much easier than creating an XPS trough. Also the foam blown into the plastic sling would result in a more a cylindrical block of foam, which would provide more constant insulating value from all directions than the squared off block with the XPS. One thing that I like about the XPS trough filled with spray foam though is that it is easier to judge how much spray foam you are going through. If you have a trough made out of 2" XPS that has an 8" x 8" open trough, you can figure out how much spray foam you will need. I would hate to buy the $600 Tigerfoam setup to do my 100' run, only to find that I was spraying too much foam and came up 10' short in my trench. I guess if you go with a spray foam contractor you don't have that potential problem.

I wasn't planning on digging multiple trenches. A 24" wide trench is more than adequate for everything that will be going underground.


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## Gooserider

The big thing to remember is that water in the ground is the enemy...  If your insulation soaks up water, it turns into a thermal conductor and becomes WORTHLESS!  There are two basic types of foam, open cell and closed cell.  Open cell is like a sponge, it absorbs water readily, and has minimal insulation value when wet.  Closed cell is essentially waterproof - it doesn't absorb water to any significant degree.

Open cell foam is good insulation, but ONLY in places where it is essentially kept dry, or where it is important to have a moisture permeable material - it is great in INTERIOR house walls, but it is not going to work properly underground!  Don't attempt any sort of "waterproofing layer" on the outside of an open cell block, as any leak will eventually compromise the entire installation.

Closed cell foam is what you want for underground "foam in place" type installs, as it is inherently waterproof, and thus both keeps the PEX from losing heat, and keeps the ground water out.

I am not an expert on their products, but my recollection is that the Tiger Foam stuff is open cell, or not suitable for underground applications (If I'm wrong, feel free to correct me :coolhmm:  )

I would suggest going with the foam contractor, and be sure to specify a CLOSED CELL foam!  That will solve the volume problem as he just sprays as needed, (and charges accordingly)  Rather than spending a lot of money on foam board, I'd consider just partially filling the trench (Maybe after dropping in your data and power conduits in the part you'd fill (Remember, you can't put power and control wiring in the same conduit, and you should keep the two types of conduit as far apart as you comfortably can...  The other option might be to see if anyone has a narrower bucket for your digger that you could borrow or possibly rent....

Gooserider


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## pwschiller

Thanks Gooserider. I just checked the technical data for Tigerfoam and all three of their products products (Quick Cure, Slow Rise, and Fire Resistant) are closed cell. They claim closed cell content of 90% or better. I have no idea what is typical in other products. I hadn't even heard of Tigerfoam until I read a posting on here where someone mentioned it. XPS sheathing (think blue or pink Dow foam) is also a closed cell foam. I believe that the foil-faced polyisocyanurate sheathing typically is an open cell foam. I will check with spray foaming contractors though when I get to the point of doing this though.


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## Batman6777

Trenching & Foaming : Great idea but you all need to take into consideration the ELEMENTS. The black plastic does deteriorate over time, the foam will crack from the expansion and contraction of the EARTH. The tree roots will weave it's way through the plastic and foam alowing water in. The Blue plastic pipe is good idea if it only had one PEX running through it ( less heat transfer from hot water out to cool water return ) but even then it should be buried four to five feet in order to get below FROST LINE. Also there needs to be a sand bottom in the trench and then sand all around to help with the Earth movement factor. FROM the school of HARD KNOCKS, commonly known as BUBBLE BURSTER.


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## Tennman

Pete, I purchased a $600 kit of Tigerfoam with the intent of injecting it into the corregated pipe along with the sleeves I used in my first abysmal underground system. I was impressed with the Tigerfoam, but it came in two tanks about the size of a standard outdoor grill propane tank. When the foamer showed up to do the second time around he came with a 55 gal drum of the stuff. I did about 170'-180' underground for about $800. I'm pretty certain I would have had to buy a bunch of those $600 kits to do my trench. I was impressed with the product, but pricey for large jobs. Regardless, even if the foam contractor was hundreds of dollars more I'd go with that 55 gal approach again just to resist the temptation of going light on the foam.

Pete, I must have misunderstood the multiple trench stuff. I can't speak to Batman's comments regarding sand etc. At our latitude the frost line is much less. I just blew foam on the dirt. We'll see. So far it's amazing this season.


----------



## plumbers crack

How is the spray foam install going to put up with ground heaving due to frost or settling? I'm only going to be able to put my lines 2' or so in the ground because of the water table in a 50' area. I'd like to save a little and do it my self but I don't want to have to do it twice, I might be better using the store bought lines.


----------



## Tennman

PC, One of the main purposes of using closed cell foam is that it is imprevious to water. If I was worried about heaving I'd go deeper to avoid soil movement and maybe blow a little bigger block of foam. The cross section dimensions of my lines are in a foam block about 12" wide by about 10-11" deep. Maybe even more depth in some locations since the process is not precise. BUT, given the heat transfer properties of the foam I'd be worried less about energy loss by going deeper (into the water table) than of foam cracking by staying above the water table. Look at the thickness of foam around the commercial products. It's probably in the neighborhood of 1" thick surrounding the PEX. Because I did it in the trench I have at least 3" all around and between my two lines. I'm not making a recommendations to you just stating that the "energy retention" capability is a function of two factors: 1) the coefficient of thermal conductivity of the insulation material and 2) the thickness of the insulation. As best I can tell, most of the commercial piping uses the same polyurethane closed cell stuff as we used in the trench. So that leaves insulation thickness as the driving factor as to which process retains the most energy. Bottomline, from what I read here the folks that purchase the GOOD commercial piping stuff do not see much loss and since your run is only 50' using the commercial stuff probably makes sense for you. But my real point is, if done right, I don't see why water table should be a factor. This is where I add my usual disclaimer asking Heaterman to chime in to correct me if I'm missing something since I've done all of ONE install, he's done many.


----------



## plumbers crack

I have to run 170' in total, 50' of it is the problem area. The line set will cost a little over $3000 for my total run if I did it in store bought line set and being a plumber I can get 500' rolls of pex way cheaper than that. I guess that I should talk with the insulation guy to find out how much deflection the foam will take before it splits, I'm just thinking of that wonderful guy Murphy and his law.


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## Gooserider

I would point out that the PEX isn't going to be overly happy about flexing and ground movement either.  While it would probably take more than the foam would, I don't really think it's a good idea to be installing any kind of line in an environment where ground movement is a concern.  

ex-Gooserider


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## HeatFarmer

Thanks of this thread I am re-assessing my Pex Runs. I WAS going to throw 2 1-1/4" lines & a 3/4" in a 4" PVC conduit which runs under the length of my house, and then spray foam it--or try--along the length..... The house will keep it dry, but it still gets damn cold under that run. NOW....however I am thinking differently. There is no room under the house to dig a trench. Barely even room to crawl.  I can really do the tench, plastic & foam because of the potential of rodents burrowing into it..... But....I am thinking of a wooden box, running the 80'ft I need to insulate. I can put wooden keepers every so often to keep the pipes up 3" and then be able to spray foam it easily. Once the foam is on I can screw on a lid. This would be a 6 x 6" ID box. The wood is "free" from my mill, so no worries there..... Crawling and feeding the pipe under the house is the biggest nightmare as 1) there is no room & 2) I've fought with claustrophobia my whole life..... used to drive me crazy when I was working construction under houses.......especially remodels. UGH!  Guess it's time to Cowboy Up and "get er done!"


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## Tennman

HF, If it is a long run in a very confined space, you could purchase a commercial foamed product like Logstor for that tough to work space. Then use a pex connector to do foamed in trench once outside. Your idea of building a wood form to "cast" the foam around the pex certainly could work... IF you can get all the spray equipment under there, hold the pex to assure spacing, and see what you're doing. Under our house in the tightest crawl space it would be nearly impossible to make all that happen. You can see from the pics we took doing our place the gear my contractor put on just to blow foam outdoors. He probably would have declined to work in my space that is very restrictive. If you plan on foaming in the trench, ask your foam contractor what he thinks. If he can do it in your form, I'd just let the foam grow out of the top like baking a muffin and not worry about a top. Best wishes and if it's that tight, I'd probably use short sections of the pre-foamed product then transition to foam in trench outside.


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## HeatFarmer

Tennman, thanks for the advice. I was wondering if I could get it all to work..... After spending around 5hrs crawling around under my house I have abandoned all plans for using that as an access route. Outdoors isn't an option either.... Check out this thread: https://www.hearth.com/econtent/index.php/forums/viewthread/86076/


----------



## Tennman

Larry, a question about your underground install:  From the pictures it looks like the pex unrolled nicelyâ€”Iâ€™ve heard it has a lot of memory and is very difficult to work with, particularly the larger sizes.

Iâ€™m going back and forth between foam in ditch using 1 1/2 inch pex and using preinsulated thermapex.  Iâ€™d prefer the larger pipe, but the cost to foam in my area is $12.50/ftâ€”that is the same price as the thermapex.  Of course, the thermapex is slightly less than 1 inch ID, so that is a tradeoff.  Plus, I can use a trencher for he thermapex; Iâ€™d have to use a backhoe for any other option so that is going to add about another $350 to the job.  I can live with the additional expense, but right now I donâ€™t have much of a window for foam because of the temp, so the other option is to insulate the pex and run it through conduitâ€”thus my question about how stubborn the pipe is.

thans for any thoughts you have

steve

Steve, The spray polyurethane firms up literally in seconds (not cured, but firmed). Yes the pex has a lot of memory but your typically dealing with very long lengths if you plan on foaming in the trench. Iâ€™ve told other folks that Iâ€™d guess the logical trade-off point of foam-in-trench vs thermopex would be 30-50â€™. That would be a relatively short run and the energy benefits of foam in trench would be marginal to just buying thermopex. So itâ€™s a cost and energy trade problem. For my relatively long run of approaching a 400â€™ round trip (170' under ground), when my house is not calling for the fan I routinely see 1.5-2 deg F loss of temp round trip from boiler and back. Thatâ€™s amazing evidence of thermal efficiency (loss of energy), which ultimately translates into less wood and time in the woods. For a much shorter run a 1-2 deg loss is still great so thermopex could make sense. The energy loss/ft length is linear so you do the math on our application. On my system Iâ€™m losing .005 degF/ft length including going thru my HX and manifold in my root cellar. I'd bet I'm losing half of that energy in my root cellar, but that loss is warming the living space above. But for a short run to get a foamer to come out and if he has minimum charges, thermopex could be the right choice for you. But from an energy efficiency standpoint it can never match my lines in a block of foam 10â€ x 12â€ cross section. I wouldnâ€™t worry about the pex memory. The foam sets so fast itâ€™s not hard to work with as itâ€™s held by the foam block as you move down the trench. 

I will add that for me, Lord willing, this is the last house I will ever own. So 5-10 years from now if I want to go to a Froling or other latest wiz bang nuclear boiler, it will be plug and play with my underground. What I got underground just can't get any better.

Best wishes.


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## AOTO

I have the Logstor pipe running 90 feet each way and have a 1-1.5 degree loss, round trip. Even when we put the pipe in the ground with the "bend", it straightens out after a bit.  I've used other piping systems in the past and the pipe you use will make or break your system's savings over oil. I went from 21 cord to 14 cord, and I expecr to do even better next year with real seasoned wood.


----------



## Tennman

If I was to use a pre-foamed product, Logstor would be at the top of my candidates. I think I priced it and for my application (170' trench) foaming in trench was about 50% less expensive when you include the pex cost. What we're learning from this sticky is that foaming in trench bids vary dramatically depending local contractor rates and competition. If foam-in-trench wasn't viable from cost or availability, this looks like the next best thing. I'm going to guess your system is similar to mine with about 15-20' of pex between the foundation and the HX. That puts your round trip at roughly 240-260' round trip for a total system energy loss of about .006 degF/ft. What I really need to do is move my in-house AZEL sensor from the HX fittings to where the pex enters my root cellar. That would allow me to measure the underground transit loss. Then we can start comparing purely the underground performance of various methods. But the physics doesn't change. If the insulating material is the same between the products compared, then the only other variable in retaining energy is insulation thickness. Thanks for the input MH. Your B&B is older than our place by about 20 years. When your place was being built settlers were just entering our area building log cabins. Love history.


----------



## cjdave

Just thought I would add some hopefully useful information to this thread, as it was very useful when i was planning my lines.  
I did 2 runs from a central location to heat 2 houses on my property. The first run was up to a 3400 sq ft log house at 200' from the boiler/storage. I did not get any pictures of that install as we were trying to beat the weather, but we did the foam in trench by laying plastic in the trench and foaming the tubes right in on top of the plastic, 2 guys 1 holding up the tubes and the other foaming, we used the Foam it green kits and it took 2 602 kits to do the 200 foot run. I felt this worked out good and would say if you have 200 ft to go 2 of those diy kits work really well, its easy to do and pretty user friendly. 
The second run was 100 ft down to a 1500 sq ft house, this time we did something different, still using the Diy foam it green kits, but Instead of the plastic in the trench, (that can be kinda a pain) we took 1" thick XPS foam board and made troughs out of it, you can see it in the pictures below, This worked really good, it was easy to make using a table saw and some 3M super 77 spray adhesive. Took 1 guy about 3 hrs to make all the troughs needed (if you cut your sheet into 6 equal strips it gives you 16' of trough per sheet) The spray foam bonds to this stuff great so no need to worry about connecting the end joints, just put it in the trench end to end. 
It took 1 602 Foam kit to do this 100' trough and worked perfect. So if you are thinking of doing this yourself that should give you a good estimate of materials needed. The foam troughs helped control foam usage to a pretty exact amount even witth some extra use at the ends to seal up to the house and shop it worked out perfect.


----------



## cjdave

more install pictures


----------



## cjdave

more installation pictures.


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## Tennman

Your approach used considerably less foam than what I did just filling the trench. Your trench looked to be about 12" so you saved a bunch of foam. I have no regrets just using lots of foam since I had a contractor show up with a 55 gal drum and foam thickness is one of the factors in energy retention. But if I was to go the DIY route this looks good. I'm not a blue foam guy for any underground, but using it to make a trough makes sense. The only thing you didn't mention was whether the 602 foam kit is closed cell polyurethane. I presuming and hoping it is. Once you get up and running be great to get some loss/ft numbers. My measurements are during conditions when the house demand is not high (maybe high 30's to mid-40's) so the circulation temps are fairly stabilized.


----------



## cjdave

Yes the foam kits are closed cell foam. the trench is actually 24", the trough is 8" wide and about 7" tall so the tubes are surrounded by quite a bit of foam. I tried to get a contractor to come do it, and they all would come, some for more than others, all quoted more than the diy kits cost me, but the big problem was scheduling, They are so busy around here they were scheduling 1 month out and if you missed your day due to weather you needed to re schedule and wait  another month. I just could not afford to have weather play that big of a role in getting this done.


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## maple1

Any worries about things shifting a bit, leading to cracking of insulation & water getting in?


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## cjdave

maple1 said:
			
		

> Any worries about things shifting a bit, leading to cracking of insulation & water getting in?


Not at all, that foam is pretty tuff after it cures, I walked on it and it didn't even make a sound. We back filled by hand some around the foam and the rest with the back hoe.


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## Mark Holden

Ok, you guys have sold me on using closed cell foam; I was planning on a 150mm rigid PVC outer tube with single component squirt foam sprayed in through strategic holes.
I'll have to get the foam kits from England; Here in southern Portugal they don't use that sort of thing. They don't insulate or heat warehouses or barns.
The locals don't even heat their houses; the old folks think central heat is bad for the health! We get down to about the frost point in winter.

I like CJ Dave's system with the rigid foam plates. They're much cheaper than the foam kits, and can be a large part of the insulation. A froth-pak kit will cost me $950 out here, double what you would pay in the US.
Foam has some flex in it in my experience; I really don't think you have to worry about ground movements unless you live on a fault line.
Tree roots will break concrete, so all bets are off if you have trees around.

Mark Holden
Odeceixe, Portugal


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## thehaas

AOTO said:


> I included a picture of the stuff I used last time. I actually used the double wrap. I will tell you this, regardless of the "wrap", if there is a pin hole in that black drainage pipe, water will get in and you will be done. You will hate the day you put that crap in the ground. The black pipe I used had holes in it when we put it in the ground and I thought nothing of it. Pipe was on a 4 week back-order and I had to get it in the ground that day. I will never use that stuff again, ever. You get what you pay for. I bought three hundred feet of the double wrap @ $9.00 foot, when I could have paid $12.00 a foot 4 years ago for the decent stuff. Now I paid $18.00 / foot for this new material and frankly I don't care. Ig I can burn 6 or 8 cords, it'll be better than 20. That really takes the pleasure out of using wood. This is the right stuff for my application. If people can foam their own, then more power to ya. The new pipe I laid in the ground will lose 0.5 degrees @ GPM running 100 foot.
> 
> http://www.urecon.com/documents/pdfs/brochures/Urecon_PEX-Flex.pdf


 i am currently building shed to house my d.s. machine boiler .had boiler in basement for 3 yrs worked great just want wood out next to unit plus feel safer and never any smoke smell in home.i had guy buy that pipe in black corrugated pipe ,then it has pex with insulation around it.very poor product black pipe brittle and damages easy his was full of water steam was coming out of pipe in his shed.i had person tell my about guy selling pipe 6 $ft what a great deal .i went looked at pipe same black pipe that fills with water looks like footing drain pipe from home depo,when i really looked close holes every 15ft ,he said i can get new must be defect no thanks.i ended up buying central boiler under ground pipe 17$ft but totally filled with dense insulation plus outer skin smooth rubber .if i did not see thats guys pipe filled with water i prbaly would of bought cheap junk from listening to people that are cheap or have no clue of quality.i am posting my project on you tube to help others like they helped me in past.you tube go type in bodyshop18336


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## shawnr

I've been planning my wood boiler installation for next season and have been paying attention to this thread for awhile.  I did some measuring yesterday and found that I can really save some underground distance depending on where I enter my basement to connect to the existing system and again where I enter the shed for the IWB.  So I guess the question is...if I can save substantial length of buried pipe by entering a building at the closest point and then run the less expensive pex along the wall or ceiling to the boilers, is it a better option.  I can always insulate the indoor pipe to reduce heat loss, and it will be in a heated space anyway.  The difference in underground pipe length ( and cost) is significant. 115 feet vs. 170 feet. give or take a few feet either way.
Thanks for your thoughts on this.
Shawn


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## scott4025

I'm  going to buy a boiler this spring and its 120 ft from where I want my boiler to my point where I will enter my basement, Has anyone heard of Zsupply pex pipe. The guy I'm buying my boiler from said its good stuff. I talked to one other guy thats been using it for 2 years and its doing great for him. Jus.t was wondering if anyone used it Its made in Michigan


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## Vizsla

I know its an old post, but the zpipe is good for snowmelt applications in your yard/lawn. Ask owners not the salesman. There are several Michigan customers that did the foam trench with. The pipe, or replaced it after a season of seeing how it performed. 127' run to HX, boiler supply 176-188, never could get higher than 168 to the HE, at 6-7 GPM. Wet, low ground, bad conditions during winter didn't help. Driving the tractor or skid steer over it was a no go.


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## Procyrus

Hello I am new to the forum and have been doing lots of research on how to do my underground lines. I almost made the mistake months ago and bought that crap wrap that ebay sells. A few of my friends have used the closed cell foam spray; one using a contractor and one using a kit. I really like cjdave's method and was wondering if he has any problems with the installation since he has done it. I dont have to worry about tree roots or anything but it will be going under a driveway that accommodates lighter vehicles. I reside in northeast ohio and I have nothing but clay to dig into. I plan on renting a backhoe and dig about 3 to 4 feet deep, line it with 6 mil plastic, then 2"  xps foam board, and filling it up with touch 'n seal U2-600, pretty much how cjdave has done.

Any thoughts, suggestions? Thank you.


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## Tennman

Please, no offense to Dave, but I fail to see the benefit of the blue foam. Lining the trench with plastic or not using the plastic allows the dirt to serve as your mold. Coefficient of Thermal Conductivity for XPS ~.035-.045; for Polyurethane blown foam ~.01-.013 per the manufacturers data. The lower the number the better the insulator or XPS is about 1/3 as good as polyurethane. My experience is XPS in the weather it absorbs water, but maybe not true for all types. So if it's easier and a better insulator I don't see why you wouldn't just blow all closed cell polyurethane. Maybe I'm missing something, but the thicker the polyurethane the better the thermal efficiency. If you go the Tiger foam route, depending on the length of your run, you'll need a bunch of those small $600 kits. If U2-600 is a closed cell polyurethane it should work. I just don't see the advantage of messing with the boards particularly if they absorb water.


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## Procyrus

They do make the foam boards closed cell. I can get 3" thick 4x8 sheets for $15 a piece from a local guy. After I cut up those sheets and make a trough out of them, no more than 12" in width, all I do is lay the pipe and spray the 80' length. Giving that those 600 kits cover 600 board feet, and I have an 80' length to fill, I will only use 240' of that spray to fill 3"over the pipe. I think 3 inches covering all sides of the pipes will be ample, almost a 6" diameter. The foam pieces will be fused/sealed together with the spray foam. As cheap as those boards are, much cheaper than the spray foam, I could figure out a way to router the sheets to sandwich in the pex, and eliminate the spray, but I need the spray to fuse the foam boards together. And with the almost half of the 600 kit left over, I need that to seal in some areas around the boiler and parts of the house/shop. I will be doing this project in a week and will take pictures as I go. 

If I didnt use the foam boards as a trough, I would need an extra 600 spray kit. They sell them on ebay for $636, the foam boards will run me about $75. Thats the difference in savings. 

Doing it this way is still costing me about $1,000. But its better than the crap I almost bought, the 3 and 5 layer junk.

Dave has also let me know that he hasnt had any issues since his install.


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## shawntitan

Procyrus said:


> They do make the foam boards closed cell. I can get 3" thick 4x8 sheets for $15 a piece from a local guy. After I cut up those sheets and make a trough out of them, no more than 12" in width, all I do is lay the pipe and spray the 80' length. Giving that those 600 kits cover 600 board feet, and I have an 80' length to fill, I will only use 240' of that spray to fill 3"over the pipe. I think 3 inches covering all sides of the pipes will be ample, almost a 6" diameter. The foam pieces will be fused/sealed together with the spray foam. As cheap as those boards are, much cheaper than the spray foam, I could figure out a way to router the sheets to sandwich in the pex, and eliminate the spray, but I need the spray to fuse the foam boards together. And with the almost half of the 600 kit left over, I need that to seal in some areas around the boiler and parts of the house/shop. I will be doing this project in a week and will take pictures as I go.
> 
> If I didnt use the foam boards as a trough, I would need an extra 600 spray kit. They sell them on ebay for $636, the foam boards will run me about $75. Thats the difference in savings.
> 
> Doing it this way is still costing me about $1,000. But its better than the crap I almost bought, the 3 and 5 layer junk.
> 
> Dave has also let me know that he hasnt had any issues since his install.


I used a 600 board foot Tiger Foam kit and came out short...
https://www.hearth.com/talk/threads/tiger-foam-let-me-down.21395/
No problems with temp loss, or the application, just a heads up that it didn't give me as much as I expected.


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## The Weimar

Hi Guys,  the higher quality the insulation and the more air space that you can create underground will greatly increase the insulative abilties of your installation. I used the german made insulated pex that has the pex nicely spaced and insulated with a very dense foam, and I pulled it through a 6 inch PVC conduit that will help if I ever have to work on it, and adds another layer of protection and Insulation. The stuff that is wrapped with insulation works, but there is better stuff available. Not cheap by any stretch....

The Weimar'


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## Procyrus

I finally completed my project, did it just like Dave but changed a couple things around.

1. I used 1 1/2" XPS foam boards and made troughs out of them, in 4 foot lengths and 4 inches in height,  I used the small cans of spray foam to assemble them. The foam acts as a sealant and an adhesive.
2. The 1" O2 barrier pex lines are a pain to deal with, even letting them warm up in the sun on a 70 degree day did nothing, so I tied a weight to then end of each one and stretched them out as far as a could to help straighten them. After a week of this they still had "memory" and coiled back up some. To separate the 2 lines i cut XPS foam into 2" strips and zip tied them together, that helped out a lot.
3. I used 10" spikes and nailed through the 2" strips, between the 2 main lines, through the troughs into the ground to center everything and to hold them in place.
4. I then zip tied the water supply line to the return line. You will see 3 lines in the photo, the supply (blue), the return and main (red). The main line is not touching anything to ensure minimal temperature loss.
5. It was 55 degrees and sunny yesterday. The touch n seal u2-600 needs to operate between 70 and 90 degrees. I stored the 2 tanks in a room with an electric heater for 3 days at 85 degrees. It is critical to keep the tanks warm before operating them. As soon as I was ready I took the tanks out, hopped in the trench and started spraying. My neighbor moved the tanks as I was spraying. I took 3 passes on everything. Its an 80 foot trench and the troughs are 4" deep. You have a 30 second window before the nozzle starts drying, but they give you plenty of nozzles. You can not spray 4 inches at once, they advise you to make passes. They were correct because I noticed if I tried to spray a second layer on right away it blew the first layer off. This stuff dries in 30 seconds.
6. The troughs did save me on a few things, to make sure the lines were centered, to hold everything down, and to minimize on the spray foam. The sections of trough should be close together as possible but the ends don't need to be glued, I had a couple turns and pitches to make. The foam kit sealed everything together. 

I had to do it this way because I could not get a spray foam contractor to come out, nobody would return my calls or emails. The pex lines, the xps boards, the foam kit, and other misc items came out to about $1,100. I was able to insulate the lines, parts of the boiler, and I have about 1/4 left in the tanks to do some areas in the basement. Doing it this way I was able to run a new water supply line to the shop that will be used for the boiler as well. The boiler has a float in the top that will automatically turn the water on and off as needed, just like a toilet tank. Down the road a may get a sealed system, which is why I bought the oxygen barrier lines. 

I am very happy how everything turned out. I would highly recommend this kit, covers 600 linear feet and is easy to work with. Much thanks to Dave and to my neighbor who sold me the boiler and helped me as well.


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## shawntitan

Procyrus said:


> I had to do it this way because I could not get a spray foam contractor to come out, nobody would return my calls or emails.


I had the same problem, LOL... Those guys must be busy... Maybe I should l look into starting a spray foam business...


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## varadhammo

I have some 5-wrap z-supply line in the trench already, luckily it's not all backfilled yet, the part that is is easy enough to dig up. I decided to spray foam it, and I had a guy come out and do an estimate for foaming around the 6" corrugated in the trench (~90' each way)

I had him do a bid for spraying just the sides and top (2") and also a separate number for doing 2" underneath the corrugated, which added another ~70% to the cost.

My thinking is that foaming underneath is not as important as sides & top, since it's already waterproof and has some insulation and air space in the pipe. Is it worth the added price to foam underneath it as well, or am I getting into diminishing returns?


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## Wood-row Wilson

Although not completely finished, I thought I would report on my foam-in-trench project coming to completion.  I ordered the Green Foam it 602 board feet closed cell spray foam and was very happy with the instructions, supplies and the product itself.  I took advantage of a rare 70 degree late October day here in Michigan to start the process.  I won't spend a lot of time repeating much of what has been said already in this thread, but much of what I learned and how I deployed my plan is a result of the learning I've found through this and other threads.  Here's a highlight of my day:

Was working with Pex B oxygen barrier tubing and with the combination of not having a straight run, it was tough to keep things separated.  Back-hoe dug trench 24" wide, so I constructed the foam board trench as described a few times above.  I was able to score 2.5" foam board which helped to beef up the total amount of insulation around the pipes.  I drilled a 2" hole through the concrete slab in both my laundry room (water heater) for the first two lines and pole barn for the other end of the four lines.  The 2 to the furnace go under the foundation and into the crawl space before the rest of the 50 run to the furnace.  In total, 4 lines through the trough.  Had the help of two others to keep the pex straight, move the foam canisters, and lay plastic over before quite quickly covering back up with dirt before the next day's rain.  All in all, it went well but ended up 10 ft short for the <100 run.  I may have been a bit liberal, but was happy with what I buried!  Here are my biggest take-aways:


Should have done more shopping on the foam.  I was referred by a contractor that I contacted to go with the DIY kits and was referred to a local retailer that had the foam, but ended up ordering the Green Foam it Brand.  I plan to purchase more foam through http://www.distributioninternational.com/.  I called recently to get some pricing and found it was very competitive.  Come to find, they have multiple locations.  Don't hold me to these numbers, but here is what I received recently.  Competitive to Foam it Green and Tiger foam, but in hindsight I should have called and purchased the 1000 board ft kit.  Less than $100 for 400 more board ft!  200 board ft –$282.43, 300 board ft– $334.42, 400 -- $???, 600 board ft– $623.12, &1000 board ft– *$717.90*
Should have taken more time to set the lines!  It was tough to wrestle four lines to stay separated, get a good amount of insulation around each, while foaming.  Many times I had to spray a bit and let it sit just to keep things straight.  I wish I gave myself more time set the lines and go back to spray around them to keep things consistent.
I plan to purchase more foam to finish the insulation of the 10' of pex that's currently exposed at the end of the first run along with what is exposed in the crawl space to the furnace.  





Thanks to all of those that contribute to this forum that helped make my install a (so far) reasonable success!


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## runnerxc

Any update on the foam underground applications?  Have you experienced any more heat loss now that it has been a few years and everything has settled?


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## Tennman

Nope. No change in performance in 5 seasons. Make the foam as thick as you can afford. Assuming closed cell polyurethane foam the only way to improve R value is additional thickness. I'd guess past 3-4" all around (including between the tubes) the ROI starts to drop off rapidly. I have +3" on my storage tanks and they feel like the ambient.


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## Greenfield Dave

Ok, I have a question for the experts. Is there ANY way to insulate my underground piping without digging it up?  I skimped on the install, mostly out of ignorance many years ago, (hadn't found this forum yet) and now I am losing waaaay to much heat.  I buried the 3 wrap PEX in corrugated drain pipe about 30" down. 

If I have to dig, I may just abandon the old piping and install new. And I WILL foam it in this time.  

Any input is much appreciated..


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## Tennman

Nope.


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## Pat32rf

Tennman said:


> Nope.


While you have to dig, I would think that a small (compact tractor size) backhoe would let you reuse the pipe after you go to closed cell foam.


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## adamant

anyone have bad results with the insulated pex you see on e bay?


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## Pat32rf

adamant said:


> anyone have bad results with the insulated pex you see on e bay?


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## Pat32rf

Never seen a poster claiming to have GOOD results. The opposite seems to be VERY common.  Maybe if you are inb  desert conditions or running overhead...


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## maple1

adamant said:


> anyone have bad results with the insulated pex you see on e bay?


 
Post 76, up the page.

Don't know if it came from Ebay but likely the same type.


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## Antman

Tennman said:


> Pete, Yes, I used the plastic sheeting just to keep the process clean. After the foam is blown it serves no purpose. I just laid it up on the sides of the trench as shown in the pics and put rocks on it every 8-10'. Ok.... can't spend a lot of time on this but a quick look shows XPS thermal conductivity at .027-.03. Urethane foam at .021. Do some quick research on line like I just did and compare Heat Transfer Coefficient. Bottom line using the spray polyurethane is a better insulator so using the sheet stuff is a waste of time and money. No need for multiple trenches, since the electrical conduit doesn't care about temperature, you can do what I did, just lay on top of the cured foam and cover with dirt. So in summary, if you compare the material properties of what you intend to use, you'll most likely find the XPS is a poorer insulator (or a better heat transfer material) than the spray, closed cell, polyurethane.
> 
> BTW, my water round trip distance is about 440'. I am routinely seeing a 2*F delta from my AZEL temp sensor in the boiler room where my water enters my 1 1/4" Pex. After prolonged idle... yeah bad but.... I frequently see the deltaT close to less than 1*F (an unbelievely sometime less than 1*F). That is an amazing .22*F/100' of run. In review, my contractor that dug up my first "go cheap" attempt using those insulation sleeves had a 12" wide bucket. So my pex is in a block about 12"W x 10"deep. Far more than most need but it was a byproduct of carefully digging up my first attempt so I could reuse my pex (mission accomplished). If I knew how I'd post pics of my AZEL digital display to so the temps to document what I'm asserting. There ain't no way the off the shelf stuff can match my 12"x10" foam brick that I had sprayed. My underground is about 180' and I paid $700 or $800 to do the trench. All insulation done in about 30-40 minutes then recovered with dirt. I would guess the cost/performance crossover point for spraying in place vs the Thermopex type stuff is maybe when the underground gets in the 30'-40' range. At shorter underground distances the losses using a Thermopex type product probably wouldn't justify the expense of a foam contractor's minimum charge.


Thanks for your sticky on underground lines. I noticed you are in Southern Tennessee. I am installing a Garn in the Memphis area and have two long runs: a 250' run (500' primary loop) and a 300' run (600' primary loop). Do you know anyone who would help me out with closed-cell PUF in trench? If you are close by maybe I could get you to stop by some time or show me you setup?


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## Tennman

Antman said:


> Thanks for your sticky on underground lines. I noticed you are in Southern Tennessee. I am installing a Garn in the Memphis area and have two long runs: a 250' run (500' primary loop) and a 300' run (600' primary loop). Do you know anyone who would help me out with closed-cell PUF in trench? If you are close by maybe I could get you to stop by some time or show me you setup?



Hey Antman, My SIL's name is Anthony and he goes by Ant. Can't help with local foam insulation contractors, but there has to be some in a city of Memphis' size. It appears your heating two buildings with one boiler. With runs that long I'd strongly consider 1 1/2" pex. Our underground is about 170' or a 340-380' round trip and I wish I'd have bit the bullet for 1 1/2" pex. I probably would have recovered the pex cost within several years in electricity savings resulting from a slower flow rate. Our home is a btu hog so we needed a pretty big pump due to the flow velocity to get to the gpm we needed. High velocity flow results in increased head due to wall resistance. You're welcome to visit to see our system, but need to schedule to make sure I'm not out of town. I added a thread about the "First Windhager in Tennessee". You'll see quite a few pictures of our system in that thread. I love using pellets, but the BioMass is still plumbed into our 1000 gal of storage so we can burn either wood or pellets. You can PM me if you have any questions. I'd be glad to run a quick calc of your gpm and head in my spreadsheet built from the Taco TD10 datasheet. Given those run lengths you'll save a ton of money doing foam in trench. Based on the foam on our storage tanks, it seems after 3.5-4" thick is diminishing return on thickness. But for underground I'd shoot for at least that much with at least 2-3" separation between the supply and return lines. PM if you have other questions, but with a system of your size I assume you're plugged in with an experienced installer.


----------



## Pat32rf

Well now I am wondering.....
Last November we did a quick and nasty install of a used P&M  ML36 at our tenants house next door. Used an old chunk of either LogStar or Thermopex for the 15' run to the house, then connected a water/air radiator in the cold air furnace line and also a sidearm heater for water. They have been keeping the temp about 24C all winter, every few days I drop off about half face cord of wood in a skid. They keep the firebox of that P&M full, but most of it looks like charcoal as the fan only starts now and then..
This has worked so good that this summer I want to relocate the OWB over to our house and run pipe back to the tenant's, about 100' The boiler would be about forty feet from our place and I had planned on foaming these runs of PEX.
Most of the run however would be along our driveway which is built on native gravel. Each fall this gravel fills with water and then freezes and heaves about 6-8". 
I expect that I would have to dig about 4' to get completely below the frost, even though the snow covered lawn only freezes 6" or so. 
How deep do you normally plant this pipe? I have a feeling that the frost will not hurt Thermopex or similar pipe, but I worry about a DIY foam trench...
Our geothermal pipe to the lake is only about 2-3 feet down....


----------



## jfriesner

Here is my experience. I got this style pipe, not sure the brand, used from a friend, it was dug out of the ground from a previous install, and I reused it on my install. I have it running 65' from my boiler to the house. It is roughly 30" deep but surfaces by the house to enter into my furnace room through the exterior wall. As you can see snow sits on it and doesn't melt. The snow fell this morning, about 8 hours ago, and it still hasn't melted off of it. Yes I have boiler going and set at 180F. I also have a 15' section of the same stuff running directly on the ground to my hot tub. When nothing is calling for heat I have a 4 degree difference between supply/return at the boiler. My loop is about 300' round trip. The stuff is amazing and definitely worth what you pay.

Also wanted to add I live in north central MN where we've already been below zero this winter.


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## Potsdam




----------



## Potsdam

Cheap and easy without over thinking much. 75 ft run from garage boiler room to an old 1880's house. dug 2-1/2 ft deep with (1) 2" blue board on the bottom and the rest as seen. All 1-1/4 heat pex insulated with standard pipe insulation inserted in water / sewer PVC glued. Ran the low voltage and 120v lines in between and electrical conduit for future needs above blue board to connect house and boiler controls. Had to make room for pex expansion in house and garage before copper runs. Solid build with no heat losses to ground. Boiler makes 180F and house receives 180F. I don't grow grass in the winter . Only regret is not heating the Water/Sewer PVC and bend verses using 45's. this is the spot I worry about year after year with the expansion/contraction. To reduce effects, the loop from the garage to house circ pump runs 100% of the time as long as the boiler is above 140F.
The reason I did this approach was witness to the failure of the highly marketed insulated supply and return pex on the market that costs runs of about $15 foot. Poor customer lost so much heat to the ground and return flows , he grew grass and burned more wood than heat his home.


----------



## warno

This question relates more to surrounding obstacles than actual lines, but it's about underground lines nonetheless. So a new tree, silver maple,  was planted this year in what was going to be my straight run to the house for underground lines. I can cross the yard at an angle but how far from that tree should I be to avoid root problems in the future? I plan on either doing "foam in trench" lines or thermopex and they will be 4 feet deep when the time comes.


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## maple1

That's a tough one. Maple roots can go far. Not sure about damage potential though. Can you move the tree lol?


----------



## warno

maple1 said:


> That's a tough one. Maple roots can go far. Not sure about damage potential though. Can you move the tree lol?



The tree was a gift to my wife and it was planted while I was at work. I already asked her that question and now I'm here asking this question. Lol


----------



## rowerwet

With thermopex it really won't matter, foamed in, it might, the other bonus with thermopex, you only need to run about 12 inches in the ground, which will avoid the worst of the future roots


----------



## maple1

Agreed on using Thermopex over foam in trench if roots are a potential issue.


----------



## warno

rowerwet said:


> With thermopex it really won't matter, foamed in, it might, the other bonus with thermopex, you only need to run about 12 inches in the ground, which will avoid the worst of the future roots



I thought it was always a good idea to get below the frost line? I live in central Illinois so the frost line does get kind of low. If I can get away from going so deep that would be a plus.


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## rowerwet

warno said:


> I thought it was always a good idea to get below the frost line? I live in central Illinois so the frost line does get kind of low. If I can get away from going so deep that would be a plus.


I lived in Maine and heated my house with an outdoor pellet boiler  with 85 feet of thermopex.
The manufacturer says 12" deep, so I ran mine there and never had an issue. 
The snow never melted over my pipe run.
It did melt over the septic tank. 
My dealer told me the 12" was just to protect it from driving vehicles over it.

Thermopex is rated to loose one degree F over each 100 feet, and my own experience agrees.


----------



## warno

rowerwet said:


> I lived in Maine and heated my house with an outdoor pellet boiler  with 85 feet of thermopex.
> The manufacturer says 12" deep, so I ran mine there and never had an issue.
> The snow never melted over my pipe run.
> It did melt over the septic tank.
> My dealer told me the 12" was just to protect it from driving vehicles over it.
> 
> Thermopex is rated to loose one degree F over each 100 feet, and my own experience agrees.




I purchased thermopex to run from my garage to my boiler. It's a very nice product. I just alittle worried about the frost line but if you're in Maine and you only buried a foot deep I think I'll be ok.

 But my main concern was the tree roots with my above post. Thermopex has a pretty tough outer shell but I also know how trees are.


----------



## cumminstinkerer

@warno from my experience installing and maintaining field tile, basically the same as the outer jacket on thermopex, the tree roots never bother the non perferated stuff, anytime we were within 50-100 feet of trees we ran non perf and taped the connections, the roots will go about that far looking for the water in the tile. we have dug some up to tap in that was within a few feet, the only issue was the roots would be balled around the tile but it never hurt it. I would consider going at least a couple feet just to stay out of the frost, I would be leery of the frost crushing the lines.  Again tiling experience shows that when we had to be that shallow the pip didn't last to long and it would get smashed just from the expansion of the dirt as it froze. Too bad its so far down there or bring the backhoe and trench it in for you for a case of beer to share when it was done lol. I have seen frost crush sch 40 PCV outlet pipes around here that were two foot deep even.


----------



## maple1

I can't see frost or roots damaging Thermopex, actually - it is actually very solid, with the covering plus foam filled.

My sister did have to have her front yard dug up in Ottawa a couple years ago from root damage though. The sewer connector pipe got broken & blocked by roots. It was a big old maple, and I think clay pipe.


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## cumminstinkerer

probably clay bell joint or possibly some stuff known as orangeburg, kind of a like really thick tar paper and still a bell joint, them roots will go in search of water and they can get through the tiniest opening. I've seen roots in field tiles where the closest tree was 150 feet away in the fence line. Mulberry is by far the worst as far as root reach, they get massive. The worst stump to push out is a toss up between elm or hackberry, they hang on amazingly well. I wonder @maple1 if maybe our soil shifts more than yours does do to the higher clay content and therfore it holds more moisture.


----------



## warno

cumminstinkerer said:


> @warno from my experience installing and maintaining field tile, basically the same as the outer jacket on thermopex, the tree roots never bother the non perferated stuff, anytime we were within 50-100 feet of trees we ran non perf and taped the connections, the roots will go about that far looking for the water in the tile. we have dug some up to tap in that was within a few feet, the only issue was the roots would be balled around the tile but it never hurt it. I would consider going at least a couple feet just to stay out of the frost, I would be leery of the frost crushing the lines.  Again tiling experience shows that when we had to be that shallow the pip didn't last to long and it would get smashed just from the expansion of the dirt as it froze. Too bad its so far down there or bring the backhoe and trench it in for you for a case of beer to share when it was done lol. I have seen frost crush sch 40 PCV outlet pipes around here that were two foot deep even.




I just wasn't sure how crazy tree roots will get trying to find water. I know many sewage lines in my area with root problems. And I didn't want that stupid tree trying to mess up my lines.


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## rowerwet

Since thermopex is a incredibly tough outer shell, packed full of dry, closed cell foam, if a root ever found a unheard of hole or crack, it couldn't penetrate any farther inside because of the foam, and wouldn't anyway because the foam is completely dry and has no nutrients or moisture for the root to seek.

There is no better product on the market for moving heat from a boiler to your home, and it is the most tree resistant product I've seen.

After 6 years or so, I sold the house in Maine and the buyer didn't buy the boiler. I dug up the pipe and brought it with me.

Then sold it and the boiler two years later.
 The thermopex was as tough as the first day I buried it.

No cracks, dents or flattening after enduring Maine winters,  and two Massachusetts winters sitting in the backyard above ground.
Currently it is buried again in Barre, VT,  bringing heat into an apartment building from the pellet boiler outside.

You can't go wrong with thermopex


----------



## warno

rowerwet said:


> Since thermopex is a incredibly tough outer shell, packed full of dry, closed cell foam, if a root ever found a unheard of hole or crack, it couldn't penetrate any farther inside because of the foam, and wouldn't anyway because the foam is completely dry and has no nutrients or moisture for the root to seek.
> 
> There is no better product on the market for moving heat from a boiler to your home, and it is the most tree resistant product I've seen.
> 
> After 6 years or so, I sold the house in Maine and the buyer didn't buy the boiler. I dug up the pipe and brought it with me.
> 
> Then sold it and the boiler two years later.
> The thermopex was as tough as the first day I buried it.
> 
> No cracks, dents or flattening after enduring Maine winters,  and two Massachusetts winters sitting in the backyard above ground.
> Currently it is buried again in Barre, VT,  bringing heat into an apartment building from the pellet boiler outside.
> 
> You can't go wrong with thermopex



Now that's a review on a product. I do have a short run of thermopex, only about 22 feet,  from boiler to garage. It is very nice stuff. I'll just steer clear of that tree and hit the other side of our yard. It'll be a better shot to the final destination of the plumbing anyway. Just takes a few more feet to get it over there. Thanks guys.


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## CRSTOVES

I'm curious if anyone has ever used Terre-Pex Insulated underground pipe?


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## PNWguy

Does anybody have a good source for Thermopex online? My local guy is not really somebody I want to deal with, and the next dealer is in the next state.


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## HitzerHillbilly

PNWguy said:


> Does anybody have a good source for Thermopex online? My local guy is not really somebody I want to deal with, and the next dealer is in the next state.



I couldn’t bring myself to pay the shipping! So I drove to the next state to get dual pex flex (Logstor). 7 hour round trip.


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## Sekhwek

Great Information.Thanks for sharing


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## Sekhwek

Great Information.Thanks for sharing.   
breakup shayari


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