Got Hardy.. Hubby is now trying to successfully plumb it

[jeanw]

House is approx 1200 sq foot plus basement......
Hubby ran a 4 inch schedule 40 white Pvc frm Hardy owb ( H4 model )thru to basement..
since it is a big OWB unit it can supposedly heat a garage etc... well he put in a black retangular sump box with a lid... in the ground at the beginning of the trench...
Because maybe we can heat( or at least keep above freezing) the big 30 by 40 big detached garage or even a future greenhouse ?????
The house is about 25 feet from Hardy concrete poured in place...
.He spent long time wrapping the 3 pipes ..(3/4 inch pex )into that dark green slitted....I BELIEVE .... 1 1/2 inch or so pipe insulation.... HE then taped on the 3/4 pex cold water line TO ALL OF THAT..........
He got it over 1/2 way thru the 4 inch pvc pipe....4 of us pushing and pulling..... thru the 4 inch PVc .. It must have got caught up and that green slitted pipe insulation doesnt "move very well in an enclosed space..... SO he pulled it all back out of the 4 inch hard pvc pipe.... Exhausting job......
exasperated he had us cut off all the tape and removed all foam slitted pipe insulation around the pex...... He will not ask anyone for advise.. but I have did some reading on here etc......
He did take some of that (foiled on one side) foam bd and put on top and sides of the 4 inch PVC pipe....that is still in the trench...thank goodness....
now This morning .He went and bought some 3/4 inch slitted foamed insulation pipe to encase the cold water line. In a hurry now he had a guy(helping us) covered the 4'" pvc back up with the dirt from the trench...... he will attempt to run that now insulated cold wtr. line into the white 4 inch pipe....in a short while here.... It is only in the 40s today and colder temperatures on its way......
what yall Seasoned OWB guys think???? COMMENTS please......
Jean
I am a bit upset that he put most of the dirt back in the ttrench.... but....

 

[maple1]

I'm no seasoned OWB user - but I see red flags all over this. The two big ones are - your heat loss to the ground from the piping will be huge, and 3/4" pex will not move enough heat.

I hope you have a lot of wood ready - and have another source of heat if the OWB doesn't keep your house warm enough.

 

[pbvermont]

Jeanw,
Maple1 is right. MANY red flags on this project. A large one, for this site and maybe a surprise to you is that OWBs are not well-liked, for reasons that many on this site believe are justified. Your descriptions of what is in your trench gives me (and most likely yourselves come winter) shivers. It would be interesting to know where your husband is getting his guidance from. Trust your instincts--things that go in the ground are critical and hard to fix once they're in. This kind of research you are doing should have been done before the project began.

 

[Z33]

Man that sounds like a mess. I cant imagine what your heat loss to the ground will be. Combine that with the normal inefficiency of an OWB and I hope you guys have a ton of wood stacked and ready to burn.

Please have your husband read this link on the proper way to run underground lines.:

https://www.hearth.com/talk/threads/underground-lines-not-the-place-to-skimp.50506/


I dont know about the rest of these guys but I would like to see pictures of this ummmm.... Set up?

 

[brenndatomu]

Please have your husband read this link on the proper way to run underground lines.: (broken link removed)

Hey Z33, the link doesn't work...

 

[Tennman]

I deleted my first reply. Please get him to read about my disastrous first year experience detailed in the Underground Sticky. For the sake of your marriage that's all I'm going to say.

 

[heaterman]

Well things are as they are and you're pretty much committed at this point so............
First this; if there are any normal 90* elbows in that run of 4" PVC you might as well dig it up. It ain't going to happen with insulation wrapped around the tube.
You could maaaaaybe get the tube through there if it's bare but no way if you wrap it.

Getting your tube in the PVC conduit:
1. Pull out the lines in the tube.
2.Get a fish tape (used for pulling wires in conduit) and run it through the PVC.
3.Tie a stout rope to the fish tape and pull it back through the PVC so you have rope hanging out each end. Use something like a 3/8" nylon or polypro rope. You don't want it too big.
4. Cut a 1 liter plastic pop bottle in half
5. Throw away the bottom half of the bottle and thread the rope through the top part.
6. Drill a 1/4" hole through the ends of your pex tubing about 2" back from the end
7. Run a 1/4" x 2-1/2 or 3" bolt through the holes you drilled in the pex.
8. Tighten a nut down on the bolt. compressing the pex a bit is OK
9. Now take the rope you threaded through the top of the pop bottle, loop it around the bolt, then tie it off
10. Slide the open end of the pop bottle down over the ends of the pex tubes.

In sequence you should now be looking at:
the rope going through the pop bottle,
the pop bottle over top of the ends of the pex lines
the rope knotted around the bolt inside the open end of the bottle,
the pex lines inserted into the open end of the bottle with the bottle acting like a sleeve to keep things from catching on the edges of the PVC.

You are now ready to pull. Usually 1 person feeding the lines into the PVC and a couple people on the other end of the rope pulling it through.
A little pulling lube from an electrical supply house will not hurt things a bit. Slather it on the pop bottle top

As far as insulation goes......it is what it is.
Wrapping the pex with regular foam insulation isn't the best but it's twice as good as nothing at all.
Being in PVC will help some. You're probably going to stay with that unless you go all the way back and start from zero, IE: an empty trench with nothing in it and no supplies purchased.

Sizing........oh boy..... the 3/4 lines could be a major derailment of the BTU train carrying heat into the house........

Two positive factors going for you are the short distance to the house and the comparatively small size of the house itself. If you were talking 150-200' round trip and a 2,000 sq ft house.....no way in the world will sufficient heat be available.
But.............
Assuming a total length out and back of 100' or less for your 3/4 pex lines you'll be able to get about 4-4.5GPM of flow.
If....... and that is a BIG IF......the heat loss is fairly low for your house, (decent insulation, newer windows, not drafty) that flow rate might just be enough to carry the heat you'll need.

Seeing as you already have the 3/4 I'd probably say try it at this point of the game.
The worst that can happen is suffering through a winter with a house which is below desired temp and you wind up digging it up and going to round 2. Which frankly I see a lot of.
Seems a good share of the types who sell outdoor stoves know very little about pumping and piping............

That should get you in the house. Now! seeing that flow rate could be marginal, by all means oversize the heat exchanger going in the plenum of your furnace.
Forget about what size your plenum actually is and hack in the largest one that you can make fit. Example; if the plenum is 16x20, see if you can cut out the plenum enough to graft in a 22x20 or 25x20

Good luck to ya

 

[brenndatomu]

Sizing........oh boy..... the 3/4 lines could be a major derailment of the BTU train

Yup, most people are surprised to find out that 1" will carry almost double the volume of 3/4"

 

[woodsmaster]

Well on the bright side, it's close to the house. If the snow is all melted over the trench this winter you'll know that your losing a ton of heat to the ground. It wouldn't cost a lot to do it right on such a short run. Should consider buying some good pipe like Thermopex or Logstor, or doing the foam in trench method with larger pex.

 

[arbutus]

Buy a 30 or 35' piece of Logstor or Thermopex. To save a few bucks maybe ask the dealer to save the end of a roll for you.

 

[harttj]

I wish you were closer. I have a 15' section of thermopex that I would sell cheap. That would get you half way.

Tim