Might redo my underground run this year

[b33p3r]

I'm pondering redoing my underground run this year and was wondering if anyone had experience with thermopex? Although I read all the warnings of going cheap on the underground run during initial install, I had no choice but to go homemade knowing I would replace it later.
Thermopex claims you should keep the install around 18"-24" below the surface. That keeps the piping out of the ground water you will see below the frost line. Does that sound right to the experts? My initial install I buried 3-4 ft deep but would love to just dig up 2 ft of ground this time around if the thermopex theory holds true.
I'm thinking of pushing thermopex through 6" pvc and spraying closed cell foam around the pvc. I pretty much have a straight shot 70' long so if it was in pvc I could probably pull the thermopex out and replace if I ever needed to without digging it up again. The foam around the pvc would also eliminate any condensation inside the pvc pipe. Thoughts?
When all is said and done this heating season I'll probably have burned near 10 cords. A friend of mine who used thermopex and the method above said he will use 7 and he heats a bigger house with same insulation values.

 

[flyingcow]

I've had thermopex for about 6 yrs. Seems to be ok. Length is about 60ft. 12 of that is exposed in my garage. The other 48ft is buried starting at 8 inches below soil down to 4 ft. I put 4 inches of 2ft wide blue board down on the section thats just below grade. I've experienced no thawing. Matter of fact the section thats exposed in the garage is cold to the touch when the boiler is shipping 195+f water. Been happy with it. But it was listed as 1 1/4 inch, but its closer to 1 inch or 1 1/8 ID. Didn't effect my set up, but if you need true 1 1/4 might not work.

I don't think it will slide inside 6 inch pvc. The stuff doesn't bend well. I had this section laid out in my truck garage for about a week with all kinds of weight(junk) on it trying to straighten it out. Once we(3 guys) grabbed it and started walking to the house, about 300ft away, the two guys on each end were almost walking together. it basically went back to a big loop. I had, what I thought would be an easy straight run from house to garage. Still a bear to handle.

 

[woodsmaster]

I used Thermopex and am happy with it. Wish it didn't cost so much, but you get what you pay for sometimes. A lot of guys have good luck with the foam in the trench. It would have saved a few bucks but not much and the guy couldn't spray it in my time frame. I also like the idea of the protective casing around it, no chance of water getting in.

 

[goosegunner]

You can also check out Logstor. I think it has a thicker casing than the thermopex. Logstor also has larger ID on the pex. The other forum of OWB users claim that thermopex has failed in some cases but little to no proof was offered. People claim the outer jacket split somehow.

Freeheat4U on ebay has some rehau pipe that is spray foamed in like thermopex and logstor.

I like your plan of making a sleeve for it. If it is not really straight it would be one heck of a pull. My logstor is 6' down with water line to my outbuilding. It is not a straight shot or I might have done the same thing.

gg

 

[BoilerMan]

When you do the pull into the PVC (great idea BTW) you can use electrical pull gel. You can get it in 1/2 gal bottles up to 5gal pails. It will not hurt the PVC or any type of plastic as it's used for wire lube when pulling into conduit. A 5gal pail will make the run that much easier.

TS

 

[goosegunner]

Does anyone know how much the yellow or orange pipe costs that they bury for gas or communication? That stuff would be great for a conduit, no fittings to ever let go and it could be curved if needed like my install. If you spray foamed that and pulled logstor through it you would have about the best waterproof, insulated underground you could ever get.

gg

 

[cityboy172]

Does anyone know how much the yellow or orange pipe costs that they bury for gas or communication? That stuff would be great for a conduit, no fittings to ever let go and it could be curved if needed like my install. If you spray foamed that and pulled logstor through it you would have about the best waterproof, insulated underground you could ever get.

gg

I did something similar when I did my outdoor wood boiler, but I just used some spare pex I had laying around.

 

[b33p3r]

Thanks for the replies. I'll also look at the logstor and rehau. Maybe once the pex gets some 180* water through it it will relax a bit. Might make for an easier pull should it ever need to be replaced. Wire pull soap works real well as mentioned. I'll save that for a repull though. Initial install I can do 10' of PVC at a time. That pull soap is not so slippery after sitting in conduit for years.
All in all the thermapex inside PVC and then spray foamed sounds like it meets everyone's approval. Thanks. I'd love to knock 3 cord off my yearly usage!

 

[hartkem]

I have had thermopex for 3 years now. I have 160' of the bigger 1 1/2 thermopex and 120' of the 1" thermopex. It is expensive but I would not have done it any other way. I buried mine below frost so I don't have to worry about freezing since my pump does not run 24/7. You wont be able to pull even the small thermopex through 6" PVC very easy. I had only one long sweep elbow and had to use a cable winch to get it through. Personally I would direct bury it with a lot of sand around it to protect from damage. With the econburn 150 I would use the larger diameter thermopex.

 

[goosegunner]

Has anyone ever used black iron pipe for there under ground encased in spray foam? Could use large pipe and not have to ever worry about melting the pex.

I think if I had a short, straight run I would consider it.

gg

 

[woodsmaster]

Has anyone ever used black iron pipe for there under ground encased in spray foam? Could use large pipe and not have to ever worry about melting the pex.

I think if I had a short, straight run I would consider it.

gg

You could use 20 ' pipe to minimize joints

 

[maple1]

Has anyone ever used black iron pipe for there under ground encased in spray foam? Could use large pipe and not have to ever worry about melting the pex.

I think if I had a short, straight run I would consider it.

gg

Interesting concept.

 

[cityboy172]

Black pipe in the ground has a lot of ways it can go wrong on you. If any moisture gets in there you'll hate yourself someday. It's gotten to where that's not even commen practice on gas line until you get into big bore mains.

 

[tmudd]

I used Thermopex 3 years ago. No problems. It would really be a bear to pull through a sleeve. could hardly bend it. I used 1 1/4" and it is 1 1/4' i.d. ABS outer casing shield is very tough. More insulation could be had in the trench install.
I never could figure how to get the poly spray in a tube effectively.
T-Boy

 

[harttj]

I've had the 1" thermopex for 6 years. Temperature readout in house is the same as boiler. 40' run. Very tough to bend.

I have about a 15' section left that i will not be using if your interested. I moved the location from my original plan.

 

[arbutus]

1" thermopex here. it does not bend easy, unless it is going back to it's original factory arch.
Doing this again, without a time crunch, I would spray foam whatever size pex I needed.

 

[b33p3r]

Was speaking to a guy I know who ran thermoplex through pvc. I was taking it a step further suggesting spray foaming AROUND all of it, NOT injecting spray foam into the pvc. My thoughts were if I ever needed to replace the thermoplex lines, I could pull them through the PVC and not have to dig it up again. I'll have to ask him what size PVC he used. He made it sound like a breeze. Perhaps he used 8" PVC????

 

[goosegunner]

I understood that you were spraying the outside. I think that would be a great if you are willing to have the extra expense.

gg

 

[BoilerMan]

Why not just spray foam the outside of the PVC and pull regular PEX through it? Use something like 3-4" I'd wonder what the heat transfer would be between the two w/o and separation or insulation. The $$$ saved over the Thermopex could be spent on extra spray foam.

TS