Outdoor Wood Furnace Info
All-Purpose OWF Discussions => Plumbing => Topic started by: juddspaintballs 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 $$. From what I've been reading, the 4" drain pipe with 3 layers of foil insulation wrapped around two lines seems inadequate at best.
So I've been thinking of using 4" or 6" drain pipe with my pex lines run inside of it. I would encase the pex lines with Thermacel insulation (http://www.pexsupply.com/Nomaco-K-Flex-118C-6-Thermacel-Insulation-for-1-Pipe-1-1-8-x-1-2-5652000-p). Alternatively, I could use two runs of 2.5" PVC with the pex insulated with that same product inside of it. Seems to me that with this type of insulation, it would block water from touching the pex (if I sealed the joints with glue) preventing heat loss if the drian pipe got punctured. Your thoughts?
Also, for pex, does it need the oxygen barrier or not?
-
Been reading lots of posts on pipe and such. Seems the general consensus seems to be Thermopex or Logstor. At $14/ft, I feel like it could be assembled as well for less $$. 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
-
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
-
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
-
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 :)
-
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.
-
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??
-
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.
-
I believe you would see a substantial drop in water temps at the house if you had water infiltration.
-
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.
-
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.
-
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.
-
whats the diffirence in temp from stove to heat exchanger? if its less than 5 or 6 deg i wouldnt think theres a problem
-
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
-
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
-
Sorry if people have read my thoughts on other pages but i want people to spend as little as possible. I buried my pex lines 30-36" deep. Each 1&1/4 pex line is in its own 4" sched 35 pvc pipe. The pex is covered in closed cell insulation with one layer of bubble wrap(type) insulation and feed into the 4" pvc. This is covered with an 18" wide sheet of rigid insualtion and covered with the soil taken out to dig the ditch. I live in maine and snow is on the ground here from december to march or april and i have not noticed any snow that has melted where my pipe is. I also have 6 temperature sensors and i only loose 1 degree on my system when the house is not using any heat. In fact one problem i have had(not a real problem) is that when my house does not need heat the OWB slowly get warmer even with no draft and because i have no heat loss my dump zone will come on every once in awhile under certain situations. I am convinced that this is a very effective and economical way of installing pipe. My system is 1&1/4 pex and it was much cheaper than anything I could buy. 1" pipe would be really cheap. I bought my insulation at "grainger" www.grainger.com a large company that sells all sorts of things, i found the insulation very cheap, stay away from the box stores. I also found insulation with a much thicker wall than the box store stuff. when buying insulation just measure the actual outside diameter of the pex and order accordingly, 1/16 bigger if anything. Buy the unsplit type rather than the split type. Tape all butt joints. With 1" pex you could wrap 2 layers of the bubble wrap around the insulation and fit it in 4" pvc. Schedule 35 is a bell end type pvc not glued, but i glued mine. This system will perform very well for you.
-
i never intended for my point of "do not ceap out" as meaning cost. i meant that remark to mean "don't think that any old insulation will do"
maine, it sounds as though you did some research and did your lines "cheaper" (in cost) but no cheaper (in quality) good luck with your home made lines. I too just want people to realize that the underground lines you use could (likely) have a great impact on your OWB's overall performance
-
Hey Guys,,, good input from everyone. Kinda' gets me thinking.
As for what is filled around my drain pipe, I filled it with sand, then 2" of high density foamboard on top, then dirt. No rocks to eat through the casing. My wood consumption has been about the same this year, if not better than last year, and we have had more snow and colder weather DAILY here in WV. Rough winter so far. (My cousin just moved here from Alaska,,, she said she is ready to move back to Alaska, where the weather is nice,,,,lol.) I have had consistent 12-14 hour burns all year. I think last year, I was loading the stove too heavy each time. Now, once the wood is gone, it can go another 2 - 4 hours before it needs wood, just heating on the 12" pile of coals. I have noticed no difference in the performance of my stove, and if anything,, it is doing better this year than last. Maybe a learning curve on my part.
One thing I did think about as far as difference from last year to this year. I had a low spot along the ditch in my yard, and I decided to fill it in with loose dirt and let it settle before I seeded it. It seems that afew other spots that I filled seem to melt off first as well. Not sure the reason, unless like Willie's ditch filled with rock for drainage, maybe the air passage through the porosity of the "new" dirt might be causing some of the melt. It only does it when the weather is right at freezing or above. Maybe I'm worrying over nothing.
I'm already making plans for a new stove for next season, just to make some changes that I think would make a better stove. I will keep ya posted as it progresses. Lots of information on here. Need to take advantage of it.
LOVE MY OWB!
-
i agree on useing sand around piping ,but i wouldnt recommend putting stone around it . stone provides the path of least resistence for water and thats the last thing you want your pipe in. if someone has a high water table i would say to bite the bullet and buy the best or the most waterproof.
-
i agree on useing sand around piping ,but i wouldnt recommend putting stone around it . stone provides the path of least resistence for water and thats the last thing you want your pipe in. if someone has a high water table i would say to bite the bullet and buy the best or the most waterproof.
my pipes run right down my lane so i put a drain tile in beside my OWB pipes. there is not much water lays in the lane for long so i presume it is working. But are the OWB pipes wet? i don't know really, but my wood consumption is always about the same, so i think my "wasted wood" what ever that is, has been the same since year 1
what i have in the ground is not near as good as what is available today. but my stove is 250 feet away from the house so for the expense of replacing it, i will just keep cutting the extra wood (that i believe is not more than 2 cords)
-
willie ,i quess the only way to know if the homeade piping we all made is effiecent or not is to install the big $$$ stuff...let me know how you make out..ha ha
-
if my lines were under 100 feet...maybe. but for 250 plus the mess of my lane again....i'll make a couple more trips to the bush!
hell i would have more in the underground pipe than i got in the stove!! :bash: