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underground piping.

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by smangold, Mar 1, 2008.

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  1. smangold

    smangold Member

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    HI, still contemplating the location on my boiler. Thinking a bit about putting it in my barn. Whats the deal with the encased pex stuff. How deep do you bury it... 48" ,or 24" with some xps insulation closer to grade for frost protection. What about a wet area? Where is the best place to get it? Thanks Scott

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  2. EForest

    EForest Member

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    Scott,
    save your cash and make it yourself with black drainage pipe and pex.
    you should bury it below the frost line (42" in our area).
    When the ground thaws you can check out my install.
    I spoke with Gary again. He's got great ideas.
    but thats a story for another thread.
  3. Eric Johnson

    Eric Johnson Mod Emeritus

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  4. ebbci05

    ebbci05 New Member

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    I would be careful to use the insulated pex stuff that comes in sections and you put if together. Up by me I know of three or four people who have had water problems. Even though they sealed the joints water still got in and cooled the water. Also, I know of one guy that had the water follow the tube inside his house and made quite a mess. I guess as long as you don't have a high water table and good ground to absorb rain water you might not have a problem. But I would make sure that the pipe going into your house is higher than the rest. On mine we had a company come in and spray foam (like greatstuff) and seal the whole thing without any joints. Gotta go hope this helps
  5. Tony H

    Tony H New Member

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    A couple of points on buried pipe do not use any joint connections under ground and you then do not need to get below the frost line. The common depth rule is 22 to 24 inches deep except at egress points with continuous pipe. It's fine to go deeper if your equipment can handle it most medium sized walk behind trenchers can go 36' or deeper, just make sure to figure your intended depth when you order the pipe.
    Standard pex pipe in not prone to cracking under ground however you do need to protect and insulate it also if the area is wet make sure you provide plenty of drainage so the pipe does not sit in water. If possible provide a drip loop where you enter the basement by going down an extra 12 inches a few feet out from the wall and then back up to the entrance hole and fill around the pipe with hydraulic cement.
  6. adamant

    adamant New Member

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    i just trenched today @24'' as per my contractors instruction.
  7. JustWood

    JustWood Minister of Fire

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    Buy the best and bury it deep with extra insulation and sand for extra protection. Do it RIGHT the first time. My dad is paying the price for not listening to me last fall.
  8. trehugr

    trehugr New Member

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    What did he do? So all of us know what not to do !
  9. JustWood

    JustWood Minister of Fire

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    He didn't listen! Do it right the first time !
  10. PAPROUD

    PAPROUD New Member

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    My installer suggested the same idea of buying the pex pipe, enclosing it in insulating foam and putting it into a black pipe, instead of buying the thermopex. Anyone else doing this? I believe the cost would be a quarter of the thermopex price. Looking at a 100 foot run and going to bury it at least 2-3 feet.
  11. begreen

    begreen Mooderator Staff Member

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    Local hydronics contractor says drop the tubing into the trench on a bed of 2" foam board, then mix up and pour (or spray) foam over it. He hasn't had a reported failure yet.
  12. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    Maybe not a "failure" (as in, leak), but how does the insulation hold up over the years? I'm not thinking that the spray foam will survive indefinitely under those conditions...

    Joe
  13. heaterman

    heaterman Minister of Fire

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    I just talked with a guy last Thursday who used the corrugated tube type insulation along with 1 1/2" foam on top for a 1" line set going to his house. He has a 4 foot wide swath of bare ground from the OWB to his house. I calc'd his heat loss based on estimted GPM and actual temp drop in the supply and it's about 135,000 BTU's. That's more than he needs to actually heat his house!!! The product I'm referring to is the generic 4" tube with a few wraps of foil/foam insulation on the pex. They are all the same, don't let anyone kid you. He ran a rag through the tube to check for water infiltration and it's bone dry, no issues there. As far as I can see you might as well put bare pex in the ground as waste money on that stuff.

    The insulated tube that comes in 10' sections works very well, IF you install it correctly. Most failures that I have seen are directly attributable to poor installation practices like improper priming and gluing, the wrong glue, gluing wet or dirty joints, not supporting the tube in the trench and leaving voids underneath it when back filling, back filling with boulders of clay and then running over it to compact, etc. etc. There's a ton of ways you can screw up whatever job you're trying to do.

    We lay bare pex of whatever size in the trench and hire a local insulating company to come to the jobsite and spray it with urethane. Virtually no heat loss, waterproof, 5 minutes and the foam is so hard you can walk on it. If you can find someone to do it, that's the best way and not all that expensive compared to other good products like preinsulated pex. It's the only method that I will guarantee.
  14. 88rxn/a

    88rxn/a Member

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    great ideas here. i ALMOST got some of that thermoPEX of and Ebay company. i will prob. make it myself also. what about using wood chips to HELP insulate in the ground?? not saying to just use the chips alone but as a added insulation suggestion.

    i may go to LOWES to see what kind of insulation i can get to do the job right the first time.

    and you were talking about priming and gluing? could you explain that better?


    **edit**
    i also may run the electric heat tape through mine for that "JUST IN CASE" factor.
  15. Chris S

    Chris S New Member

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    wood chips, or as some call them "lightweight aggregate" will hold a lot of moisture, eventually rot, and settle- wouldn't be my choice
    I've had good luck with the uponor preinsulated product- very low heat loss, about 10/ft though for 1"
    Spraying the trench sounds interesting, but how much did that cost?
    Chris
  16. smangold

    smangold Member

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    I spoke with a boiler guy yesterday about the piping. His thoughts were to dig a 4' deep trench with 6" of crushed stone at the bottom and then two layers of 2" blueboard followed by 4" pvc pipe .Surround the pipe on the three other sides with 4" of XPS also, back-fill, vacuum a rope through it and pull 2 pcs. of 1" pex through. This would allow you two change out the pex if necessary. The stone should be drained to daylight. 4" pvc is pricey though. maybe two runs of 2" would be just as good. Or is there other pipe that would work?
  17. heaterman

    heaterman Minister of Fire

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    RE: Cost for spraying the trench

    You'd have to check locally with an insulating company near you. The company I use, Alper's Insulating out of Traverse City Michigan charges a $75 trip and setup fee which is waived if they're spraying more than 50 or so feet. From there the charges are based solely on the amount of product they use. When quoting a job, I use a figure of $7 per foot for normal 1" or 1/14" pex as my cost and that usually comes out pretty close. For larger sizees of pex it runs a little more. I'm VERY pleased with the way it works. We did one this fall that was 283' long using 2" pex. We wound up with a foam thickness of a good 4-5" on all sides of the pex. The tube is a bit over 2' down and goes under a drive with heavy farm equipment running over it all day. There is no sign of any heat loss even under the drive. Using my Fluke digital thermometer/thermocouple, I can read a temp drop of only .7 to1 degree in the 283' depending on the water supply temp. The 1 degree reading was at 185* water temp. That's a far cry from the 30*+ I measured at the other poor guy's place last week using the corrugated stuff with foil/bubble/foam/whatever as lining.

    Insulating the tube is the absolute last place to try a save some $$ by going with a cheaper product. It will cost you more labor, more wood, more wear and tear for the life of the system.

    Do it once. Do it right.
  18. mtfallsmikey

    mtfallsmikey New Member

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    Getting ready to do mine...1" PEX, Armacell insulation, going to try to pull both lines thru 4" ADS, if unsuccessful, do separate runs. The 1" PEX is STIFF! Any ideas on how to unroll on the ground first to get it to take a "set"?
  19. Chris S

    Chris S New Member

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    Armacel has very low value!!
  20. Tony H

    Tony H New Member

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    If it's a sunny day lay the pipe out in the sun for a few hours first and then wrap one coil around a tree or other large round fixed object and secure then unroll against the coiled direction and stretch to another fixed object and let it sit for a while.

    This is how I uncoiled the Logstor dual pex insulated pipe that I buried it is about 4.5 inches diameter and quite stiff so I used my ATV and a logging chain to help it along, you can use quite a bit of force just make sure you don't kink the pipe.

    When pulling thru the other pipe you might want to use some pulling lube and a helper to make sure it slides thru ok if it's a long run.
  21. smangold

    smangold Member

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    Heaterman, Are you talking about the closed cell foam contractors spray in wall cavities. Also do you suspend the pipe in the trench or do you use rigid underneath( to allow foam under the pex.) Thanks for all the good info.
  22. Chris S

    Chris S New Member

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    Heaterman-
    That seems like a lot of time , trouble etc.
    I have used Ecoflex ( from uponor) & found it to be easy & fast to install but expensive. I'm not sure if what you're suggesting is any less expensive though, or any better. Did you use one of the prepackaged products & find it unacceptable, or do you believe your installation is better for all of the reasons stated above. Not even sure of the availability of ecoflex larger than 11/4"

    Chris
  23. heaterman

    heaterman Minister of Fire

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    The product usually sprayed in a house is not urethane based. It's a much different animal. The urethane these guys use "blows" like Great Stuff x 3 and I'm not even sure you can use it in a structure unless it's in a sealed space. When dried (just a few minutes) the foam is closed cell in structure so it's totally waterproof. As I said before, I can put all my 228# weight on a pile of it in maybe 2 minutes. It's very rigid when cured. The installing crew told me they have jobs that are right in the water table with no issues whatsoever and from the performance of their product, I see no reason to doubt them.
  24. heaterman

    heaterman Minister of Fire

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    I've found that this method gives us a little more flexibility in the installation. It may take a bit more time but it would be minuscule. The bare pex is much easier to handle than the Ecoflex. Doing it this way, we nearly always wind up with 4" minimum all the way around the tubes which is much better than anything else I've found. Most times it's more like 5-6".

    The guy running the gun in the trench will lift the tubes with his foot and apply a swath under them. The foam blows and begins to harden in about 5-10 seconds at which point he drops the tube on the foam and covers the sides and top. He works his way down the trench in 3-4 foot increments.

    Again, when insulating your underground piping, the term "good enough" should not even be in your vocabulary. So what if it's $.50 or $2.00 more a foot, which I have not found to be the case, it's the best money you can spend.
  25. DKerley

    DKerley New Member

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    Hello,

    My installation required 100" of buried 1"Kitec pipe for the shop heat. The product that I used is made by Urecon (http://www.urecon.com/english/english.html). I buried it 3' deep (within the frost zone as our frost line is far too deep to practically get below). The Urecon pipe is basically 4" PVC pipe with a layer of foam insulation then, a waterproof barrier wrapped around it. The outside diameter then becomes 7". It comes in 10' lengths which you can glue together and then seal the joints. On my installation, there is no measurable heat loss over the total of 160' of pipe length between the boiler and the shop heater.

    The product was fairly expensive (about $12.0 ft. plus shipping). The nice thing about it is that I was able to run a potable water line inside the pipe as well after the heating installation was completed.

    Cheers
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