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Author Topic: More water line discussion  (Read 10875 times)

juddspaintballs

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More water line discussion
« on: February 11, 2010, 05:15:10 PM »

Been reading lots of posts on pipe and such.  Seems the general consensus seems to be Thermopex or Logstor.  At $14/ft, I feel like it could be assembled as well for less $$.  From what I've been reading, the 4" drain pipe with 3 layers of foil insulation wrapped around two lines seems inadequate at best. 

So I've been thinking of using 4" or 6" drain pipe with my pex lines run inside of it.  I would encase the pex lines with Thermacel insulation (http://www.pexsupply.com/Nomaco-K-Flex-118C-6-Thermacel-Insulation-for-1-Pipe-1-1-8-x-1-2-5652000-p).  Alternatively, I could use two runs of 2.5" PVC with the pex insulated with that same product inside of it.  Seems to me that with this type of insulation, it would block water from touching the pex (if I sealed the joints with glue) preventing heat loss if the drian pipe got punctured.  Your thoughts? 

Also, for pex, does it need the oxygen barrier or not?
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willieG

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Re: More water line discussion
« Reply #1 on: February 11, 2010, 05:33:03 PM »

Been reading lots of posts on pipe and such.  Seems the general consensus seems to be Thermopex or Logstor.  At $14/ft, I feel like it could be assembled as well for less $$.  From what I've been reading, the 4" drain pipe with 3 layers of foil insulation wrapped around two lines seems inadequate at best. 

So I've been thinking of using 4" or 6" drain pipe with my pex lines run inside of it.  I would encase the pex lines with Thermacel insulation (http://www.pexsupply.com/Nomaco-K-Flex-118C-6-Thermacel-Insulation-for-1-Pipe-1-1-8-x-1-2-5652000-p).  Alternatively, I could use two runs of 2.5" PVC with the pex insulated with that same product inside of it.  Seems to me that with this type of insulation, it would block water from touching the pex (if I sealed the joints with glue) preventing heat loss if the drian pipe got punctured.  Your thoughts? 

Also, for pex, does it need the oxygen barrier or not?

i believe you need the oxygen barrier and i think it is possable to make your own underground pipe, i would suggest if you do  make your own and are saving bundles of money, put your home made pipe inside another non perferated tile so you have the option of pulling it  out if ever needed and also i believe that heat loss from your home made pipe to the air in the bigger tile is less than from the ground surrounding the pipes
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willieG

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Re: More water line discussion
« Reply #2 on: February 11, 2010, 05:38:47 PM »

also i forgot to mention i used pex-al-pex it costs more but i liked it for infloor heating it expands less and keeps it's shape much better i think it is 30 or 40 percent more money than regular pex it may not be your choice for undergorund but you might consider it if you do in floor radiant
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rosewood

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Re: More water line discussion
« Reply #3 on: February 13, 2010, 08:46:35 AM »

i have had good performance from homeade  pex piping , i started with 2 rolls of 100' pex ,slide foam insulation on,taping each joint, then wrapping both insulated lines with sill seal foam. finally feeding threw 6'' corragated flex pipe. some say this is not as good ,but i have only few deg loss over 100' . for the cost of less than  $ 200  [ already had 6'' pipe from left over  job]  even if pipe was purchased still only another $100.  that breaks down to $3.30 a ft ,better than the 12-14 dollar a ft.  thats a lot of $ . dont know what type of stove you have ,but alot of factory models dont insulate very well and have more heat loss there than the loss in pipe
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juddspaintballs

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Re: More water line discussion
« Reply #4 on: February 13, 2010, 09:58:46 PM »

I don't have a owb yet, but I'm most likely going to be purchasing a Heatmor 200css with shaker grates.  I know a few people with that owb and they all perform quite well and haven't had any problems yet.  One person I know with that owb is a farmer that really does no maintenance on his machinery and everything around his farm is falling apart, but his Heatmor is still running very well.  I figure if he can use and abuse it like he does with everything else and not take care of it and it's still working, it should hold up quite well with a little TLC.

Priced out my water line idea last night for 4" and 6" drain pipe together and I came up with about $6/ft.  I took a look at my father's water lines today: two 1" lines and two 3/4" lines (for DHW) going to/from the owb all wrapped together inside one layer of foam foil insulation without anything separating them.  The cold water from the well is running to the owb's in one of those 3/4" lines.  I think I can do better than that :)
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rosewood

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Re: More water line discussion
« Reply #5 on: February 14, 2010, 09:55:54 AM »

 i think you can do better too. i dont see the need run anything other than 2 1'' lines to service needs not sure what type of  heating system you have currently. i installed boiler drain spikot in return line in basement to fill owb , i shut off pump turn ball valve on incoming water, connect water hose from inside spikot  to spikot on return line and fill .  that way will eliminate third line,leaving more room for insulation in pipe. most will agree to insulate lines seperate than wrap together . that way your not cooling incoming water with return water.
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MarkP

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Re: More water line discussion
« Reply #6 on: February 21, 2010, 01:26:17 PM »

I'm on my second winter with my homemade OWB and I insulated and installed my lines myself.  I was really happy with it until about a week ago. 

On installation, I used two lines of 1" oxygen barrier pex tubing, and slid lengths of unsplit, closed cell foam sleeves over each.  I taped each joint in the foam, and taped the two lengths of pex together.  Next, I put three wraps minimum of HVAC bubble wrap insulation over that.  None of this will absorb water.  Next I burried a 6 inch corrigated culvert from the stove to my house, with sand all around the pipe, and covered it with 2" high density foamboard insulation before I filled the ditch in with dirt.  The ditch was 38" at the stove, and to get under my house, I brought it up to 28" as I passed under the foundation.  I slid all my lines inside this pipe.  I really thougth I had this one whipped.

About a week ago, I noticed in all the cold and snow, that the line from the house to the woodburner had less snow on it.  As the days progressed, that part of the yard melted first.  I'm not sure what could have caused this.  I thought maybe one of my heater lines was leaking, but there is no obvious leak, and I HAVE ADDED NO WATER since I fired this thing up in October. (Thanks to everyone that helped out last year with my "steaming" issues.)  I checked the water today, and it isn't down even a quarter inch.  It is performing the best that is ever has.  I will never be without a OWB.

Any ideas on the snow melt??  I will be pulling the lines out this summer to take a look.  My guess is that maybe the corrigated drain pipe I ran my lines in has a leak, and the water has filled the pipe, and it will transfer heat, when the air space would not. 

Ideas anyone??
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juddspaintballs

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Re: More water line discussion
« Reply #7 on: February 21, 2010, 01:56:29 PM »

Even the best insulation still allows a little heat transfer.  If the ground around your lines only warms up 2 degrees, the snow on that ground will melt before the rest of the ground.  If you have no performance issues inside, I wouldn't worry. 
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m21221

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Re: More water line discussion
« Reply #8 on: February 21, 2010, 02:00:56 PM »

I believe you would see a substantial drop in water temps at the house if you had water infiltration.
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MarkP

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Re: More water line discussion
« Reply #9 on: February 21, 2010, 03:37:39 PM »

I haven't checked temps to see if there is a drastic drop, but I am heating a 1680 sq. ft. house, and 1000 sq. ft. of my garage, and have seen no difference in performance.  I just don't remember seeing the snow melt over the lines last year as it has in the past week or so.  Everything still seems to be working great.  Snow is still laying on the roof of the woodburner just fine. 
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mikenc

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Re: More water line discussion
« Reply #10 on: February 24, 2010, 08:08:57 AM »

If you have a water leak even a small one it will show up by water level dropping in your system over time. Someone has already said the best insulation will allow some heat transfere. If water level dosen't drop I would not worry about it either.
Are your lines solid or are there fittings under ground?

You could always dig down to your line in spring and cut window in casing and check if that would give you peace of mind. But you would have to make a patch on caseing.

If it is heating good you are not loosing water I would say ok.
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juddspaintballs

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Re: More water line discussion
« Reply #11 on: February 24, 2010, 10:42:52 AM »

I think he means that he thinks he has water intrusion into his water barrier around his lines.  Water directly touching the heated water lines will transfer heat away from the water lines quickly into the ground and it should present as noticeable temperature drop by the time the water enters the house. 
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rosewood

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Re: More water line discussion
« Reply #12 on: February 24, 2010, 03:10:15 PM »

whats the diffirence in temp from stove to heat exchanger?  if its less than 5 or 6 deg i wouldnt think theres a problem
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willieG

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Re: More water line discussion
« Reply #13 on: February 24, 2010, 03:28:57 PM »

one good way to tell is yoru wood consumption for the year?

is this winter comparable in terms of winter temps to last year? If so then wood consumption should be close as well.
if wood consumption goes up by 15 or 20 % then i would say your insulation has been breached

and fellas, i don't care what you put in the ground, if it isn't a factory seal from end to end or welded and tested and laid in with protection (like clean sand) it will eventually leak. plastic sewer pipes will crack..glued joints will leak ,eventually chances are even the logstor or other pipes that are simalr will leak if not surrounded by good clean sand. I have seen the old steel in ground floor hoist leak in less that 25 years due to a stone in the clay rubbing on the outer casing of the hoist. the underground part of your OWB is about the most important part of your system
i am considering on my next adventure, to buy pipe at the scrap yard and weld the joints and pressure test them then run the logstor (or similar) pipe down this pipe. There should be no breach of this system for my lifetime (what is left anyway)

DO NOT cheap out on your underground lines
« Last Edit: February 24, 2010, 03:53:02 PM by willieG »
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willieG

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Re: More water line discussion
« Reply #14 on: February 24, 2010, 03:47:10 PM »

here is another thought? when you installed your underground lines what did you fill the ditch back in with?

in my trench i put a drain tile below the heat lines and after my layer of sand i filled the trench with round 3/4 inch stone to make draining better, my lines also show when the temps get to or just above the freezing mark. I am not sure but i like to think that is because as the sun starts to melt the snow and the water trickles down there is a lot of air space around the round stone and so it thaws quicker than the dirt beside the trench. This makes it look like there is a terrible leak of heat from the lines. where my trench crosses my laneway i burried it  5 feet deep and every where else it is about 3 feet  but the trench always shows like it is leaking the whole way at the same time. i would have thought that the shallow spots would show first if the pipes were leaking?

just a few thoughts on the matter. i know that my pipes do lose some heat but to keep the ground thawed for 250 feet would require a lot of BTU. I had a dealer one time (trying to sell me logster piping) that my 250 foot trench that was showing as the temps raised to just freezing or above was actually costing me upwards of 4 cords of wood a year. Well, i burn usually between 8 and 10 so if i took 4 off the 8 that would mean i should be able to heat my  century old farm home on 4 cords of wood. i found that hard to beleive so i have not dug up and replaced my pipes. even if i took 4 off of 10 that would leave 6 cords and i still find that hard to beleive as folks with these new fangled "high efficiency OWB" have a hard time getting by on 6 cords for a newer home.

and if my pipes are costing me 2 cords a year, compared to digging up the lines and replacing them with the newer expensive pipes, i'll just keep cutting those 2 extra cords. but if i was starting brand new, i would use the best underground i could find
« Last Edit: February 24, 2010, 03:51:23 PM by willieG »
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