Energy transfer line problems

[tigermaple]

Hi, I’ve got a question for the boiler crew. I have a Greenwood 100 located 150’ from my house running a baseboard system in a 180 year old farmhouse with basically no insulation. My energy transfer lines are inside 4” corrugated plastic tubing and buried 4.5’ underground. The system had no problem heating my house to 75º when 15º outside. A few weeks back the 4” tube got hopelessly filled with water when one of the pex couplers let loose right at floor level. Repairs left the tube severed 1’ below the floor, exposed to ground water. Well now I’m burning near twice the wood and the house takes forever to heat up.
I feel i need to bite the bullet and replace the lines. What is the best stuff to get? I cheaped out and got the tube from ebay for 4 bucks a foot so I need the good stuff.. What about MaxxR? Seems tricky.
I greatly appreciate any suggestions
Thanks,
Pat

 

[Eric Johnson]

Welcome to the Boiler Room, tigermaple. I love the Finger Lakes.

You just made the case for keeping your insulation dry.

There are a couple of other threads here on the topic of underground lines, but it's not something I know much about. One of our members, barnarist, recently replaced his el cheapo underground lines with some stuff from Central Boiler, so that's the only recommendation I can make. Maybe somebody can explain a good DIY approach as well.

 

[Bartman]

Tigermaple,
What type/brand coupling was it that let go, and how did it do it? Since the costs of copper are so high everyone is using PEX, I have had my preferences and theories, but they could be wrong.

 

[deerhuntrer]

Central Boiler makes a thermopex. Its an pre insulated line that is prefab and it works awesome. I do not know if you can retrofit it to your furnace, but my brother in law bought it for his aquatherm. Its about 10.50$ a foot.

 

[tigermaple]

Thanks for the suggestions.
Eric,
Thanks, Clinton area is very nice also, lots of woods. Yeah, wet pipes are no good. I knew right away I was screwed, but the heat loss was even more than I thought. 5º below last night and 6" snow and many spots along the line melted through.

Bartman, The joint was crimp on 1" fosta pex to regular 1' pex. The ground settling is what the installer said.
Darren,
I checked out CB's themopex and it looks much improved over mine. 2 grand more in stings though.

 

[ericjeeper]

why bury the lines so deep? This has me puzzled? My lineset is in a 5 inch non perforated corrugated pipe. I wrapped each 1" in armorflex.Then wrapped the two together in foil faced bubble wrap. Then shrink wrapped it all.. Then pulled it though the 5 inch , and then spray foamed the crap out of each end. especially the end going into my storage tank.
Ok now my house is on a slab.. so I had to be above it on the house end.The entrance to the tank is only 9 inches from the surface on the tank end.. so I buried it all about a foot deep. The ground freezes right around my pipes. snow stays on the trench. Obviously I am not losing any heat to the soil.
If I was going to enter a basement I would bury with a fall from the boiler to the basement cutout if possible.So if groundwater ever got in it could just run into the basement.

 

[Bartman]

Is the fosta pex a different size than regular pex? I know some brands are supposedly not compatible, I know when I crimp PEX with my Zurn crimper on Zurn fittings with Zurn tubing there is no way it's coming apart, unless I cut it.

 

[tigermaple]

The idea behind burying the lines was to get below the frost line and I was running water pipes to the barn. Its level all across so the pipe is an underground "u" filled with water. Is it better to be in ground water or frozen in dirt? Maybe I should go shallower for the next line?
Fosta pex is pex covered with aluminum. It don't sag and flexes like copper.

 

[Eric Johnson]

I use Mr. Pex pex-al-pex and it's an odd size. I have to order fittings from Cozy Heat because nothing else works on that stuff. It has an aluminum tube sandwiched between two layers of plastic.

 

[mikeyny]

My lines run above ground. 2 inch black iron bought from the local scrap yard for next to nothing on 2 layers of 2 inch foam covered in 9 inches of fiberglass and some heavy duty old discarded lumber wrapping. It works great but looks pretty funky. It stays covered with snow all winter. It is all in the back along the fence line so not too noticeable. I run straight water, never froze yet,(knock on wood). When I first set it up I had it wrapped in white plastic left over from something and my kids made me change it because they said it looked like the worlds biggest tampon in the back yard. I would love to put in a nice pex line underground but cant come up with the dough. And anyway, since this works (4 yrs and counting) why change it.

 

[Bartman]

It seems as though prefab pex lines can be made relatively easy. There is so much material available these days compared to when I built my system years ago. On eBay I saw the foil faced bubble wrap insulation pretty cheap, foam pipe insulation is cheaper today than it was 20 years ago, corregated pipe is available in most home stores as is PEX. I really think you can make your own underground lines as good, if not better for less money, you just have to put in the time.

 

[Eric Johnson]

I agree with Bartman on the DIY. The most important thing is to keep it all dry. With long lengths of underground pvc readily available, I don't see why you couldn't put together a couple hundred feet of supply and return pex insulated within a continuous run of drain pipe that you can pick up at any ag supply outlet. I bet you could do the whole thing for around $5 a foot, not counting your time, of course.

 

[wdc1160]

You already got the 4" pipe. You already got the pex-- I assume.

get this and your set -- for less than a dollar a foot marginally.

link

about 150 and your back in business. Good luck

 

[rsnider]

i made my own lines :
1" pex-all-pex mr. pex covered with foam pipe insulation about 1-2 R (?) taped together
made a box of 2" rigid foam board just big enough for the 2 lines R 10.
wrapped box in heavy mill plastic
tapped with duct tape
wrapped in silver 7x10 tarps and tapped again.
in trench bellow frost line.


did this with another project and no signs of failure yet going on 5 years now. heat loss a minimum. i know that water has to be around the pipes but i don't see the harm to its R value since its not fiberglass insulation maybe im wrong on that. so far so good. the lines are actually pretty strong after all put together.

 

[ISeeDeadBTUs]

My GW is about 75' from the house, but almost two stories higher in elevation. In keeping with the rest of the project, I spent as much money as I could by getting CB's Therma-pex. The stuff is great so far. Most of the line is not buried yet, as I have some more earth moving to do. The pex terminations/fittings seems to be the weak spot in this route. Oh! and trying to fish 90' of it through a sonotube in a concrete slab where *someone* made the angle 90 deg :smirk:

 

[henfruit]

do you run any gylcol in your system. i have mine in the basement but i think that will change this summer . i think it it will go in a shed i will build in the yard. i have been using split wood not having round this year, the gw seems to smoke a lot when just load it up. what are you getting for burn time? thanks

 

[tigermaple]

Thanks again for the input. I think I’m gonna bite the bullet and buy the themopex. I can’t salvage my old pex as, after repairs, it is to short, and I don’t want couplers underground. So then homemade is costing 6.50 a foot and an R value half of themopex+ labor. I’m going to bury it above the other stuff 2.5’ down with 1’ foamboard over the top.

Now the question is 1” or 1.25” pex?

I understand spending as much as possible, this whole project is more over budget than the “Big dig” I’m hoping for a break in monetary input at some point.

Even still, I like the greenwood a lot. I burns everything I can pick up and burns fresh cut hickory in a pinch. It does smoke at start up but burns clean(no visible smoke) in less than 30 min
.
HenFruit
Before the lines flooded to much heat was the problem. I would easily get 10-12 hours 3 12” x17” sticks of hickory, beech or maple at 25-30% moisture content. Rounds burn much longer than split. Also, if wood is loaded lengthwise as opposed to rolled in, it will disappear before your eyes. I do use glycol.

 

[heaterman]

Another way.

We use regular pex of the appropriate size in a trench usually only 2' or so deep. I hire an insulating company to come a spray it with urethane foam right in the trench. Usually averages $6-7.00 per foot depending on their travel time to the job site and the diameter of the tube covered. We wind up with a water tight insulation package that averages 3-4" thick around the pex. On all the jobs we have done in this manner there is virtually no detectable heat loss unless the loop is over 350-400' round trip. As an extreme example, we installed a loop of 2" pex that is 564' there and back this fall. When circulating the main loop with no connected load, I can measure a temperature loss of only .8* with 180* water. The loop passes under 2 driveways, one of which gets heavy agricultural traffic. (think equipment weighing 80,000 lbs.+) There is no sign of any thawing of the ground anywhere, even on the drives. The foam they use becomes so hard that you can walk on it within 5 minutes and not leave a footprint.

Another product I like is InsulSeal which is 10' lengths of 4" PVC coated with 2" of urethane, wrapped in PE plastic. It is insulation only allowing you to pull your choice of pex inside it. The drawback to this is that I have seen improperly glued joints fail with settling allowing water to get in the tube and cause the same problem you have. If you use it, make sure the bottom of your trench is smooth, level and compacted to properly support the tube.

You may be able to alleviate your present problem by fishing a piece of pex or stiff hose into the insulation jacket and taping it to a wet-dry vac. You don't have to go in far, just enough to get down to the point where your tubing reaches its average depth. Give it a suck and then let it rest allowing the water to flood back to the point your "hose" is at. I've cured a couple like that and it may allow you to get through the winter without growing tulips in February over top the lines.

Tubing and the insulation thereof is not a place where you want to save money.

 

[tigermaple]

Thanks Heaterman, Foam is a very interesting option. I going to look into to contractors on Monday. I’ve tried to get a tube down the pipe to pump out water but with no luck.
For 150’ underground and 75’ inside (400’ loop all together pumped) by a taco 10 - do you think 1” pex is ok or should I rip it out and start over with 1 1/4” pex?

 

[heaterman]

Ran some number on my design software using the following criteria. 400' of tube with 8 elbows (a guess) and 2 ball valves(also a guess).

Using 1" tube a 0010 will give you 4.37 GPM
Using 1.25" tube it will do 7.21 GPM and..........
with 1.5" you'll get 10.63 out the end.

Two questions should help you make your choice

What do you actually need, in other words what's the heat loss of the structure you're heating and how much of a factor is the electricity required to run your circ . Consider this...... a 007 burns .8A while a 0010 wil draw 1.7A. Assuming your circ runs 24/7 this can add up to a pretty fair $$ difference over a year.

The above mentioned 007 will do

1" = 4.04 GPM
1.25 = 6.51 GPM
1.5" = 9.35 GPM

Pencil out the operating cost using your local cost per Kilowatt hour and I'll bet you'll be surprised. It'll also help you make up your mind as to tube size.

1" pex has become the default standard of the industry mainly because it's what most of the OWB dealers feel the traffic will bear and because larger sizes are not to common. Is it always correct? Seldom.

 

[G-rott]

[quote author="tigermaple" date="1199426404"]. Is it better to be in ground water or frozen in dirt? Maybe I should go shallower for the next line?

Stay well above the water table...ground water keeps absorbing heat and "washing it away".

Garett

 

[tigermaple]

Thanks again to everybody for the many ideas. Heaterman, your thoughts gave me much to ponder. But I'm have problems finding a contractor. So it's back to thermopex or MaxxR 2' foot down (above waterline) buried in sand and maybe 1" foam board, then dirt.
Hope to dig next week.
Pat