Insulated buried pex.

I looked through all the threads in this forum and did not see a thread related.

Im getting ready to dig for the buried pex from owb to the house and shop. Ive looked at some pex options and spoke with several people.

There are two types Im interested in. First is this. 5 wrap 1" o2 barrier. States .6* loss over 100'.

Up side, I can get it shipped to my door for $6 a foot. I will need roughly 150'. I can pull wiring in along side insulation for thermostat.

Down side if the outer piping tears/breaks there is a good chance of water entering and loosing btu's. I would put down a layer of chips around this to help avoid and rocks coming in contact.

This type is closed cell, 1" o2 barrier also but there really is no chance of water entering. $9.5 a foot and I would need to lay another conduit along side for thermostat wiring.

Any experienced help would be greatly appreciated. Thank you.

 

1/2 or 3/4 conduit is pretty cheap. and gives you the ability to replace the wires later if needed. You can also run power for circulators and lights to the boiler house through the conduit.

 

I think the bubble wrap would degrade over time. The closed cell ISO with the heavy outer shell, I believe, would last forever.

 

john my buddys owb has 5 or 6 water lines in it he got it from georgia or north carolina

 

Im pulling power from the shop panel. Im leaning toward the closed cell. That way I wont have to mess with layer of sand. I did have a long chat with the manufacturer. Only down side to closed cell is its very stiff and hard to work with.

 

Yeah, I saw some of that Dall. I only saw the layered wrap in that though.

 

First and foremost, remember that underground is not the place for skimpimg or saving money. Unless you like doing it more than once....

With the wrapped pipping, notice that there is only a single layer of insulation between the supply and return pipes. Leads you to believe that there has to be a lot of heat transfer between the two pipes especially since you're talking 150' distance, no?

The closed cell is a bear to work with and more expensive, but worth it IMO.

Back in the early 90's, I built my own insulation box for the lines, It worked fairly well, but then, only because I lived in a all sand area. Digging by hand was a breeze and there was never an issue with ground water. Under certain circumstances, it can be done.

Where I am now, I used the closed cell piping and am satisfied with it. Looking back though, I would have added a 2" thick sheet of blueboard (by probably the width of the trench 16" or so) above the piping for added insulation.....as I do see a depression in the snow cover throughout the winter months. It usually takes about a week of no snowfall before you will notice the level where he lines are buried to begin settling more than any where else.

I also laid the underground rated elec in the same trench.....but did not have to run a T-stat wire as there is an aqua-stat on the OWB.

Good luck and post some pics!

 

Going to have to make the same decision next year (I hope).

 

yooperdave, By bluebird do you mean the DOW styrofoam insulation like what goes on houses? I'm installing an OWB soon and would appreciate more detail on any install tips. Thanks!

 

Yeah, that is what we call the sheet styrofoam around here...."blueboard" pink and yellow too. I think one of them is designed specifically for ground contact.

The box I made was not sealed tight like the premade stuff you can buy; further, it was just wrapped with duct tape to hold it together. but the only reason it worked for where I was in a previous life was because of the all sand conditions. The dealer of the OWB suggested it and it worked out well for that application.

If I was there now-a-days, I would not do it again; rather, I would use the stuff in the second pic above. That was about 25 years ago and my physical condition was still hiding the defects that are apparent now!

 

We use the 2” blueboard to keep water lines from freezing in the places we can’t get deep enough. It makes a big difference - places in the barnyard that get snow plowed off all winter and the line is only 3 to 4 feet deep have not frozen.

We had a wide trench because we were looking for a seam to get deeper with. I think we put in the 2’ wide sheets above the pipe.

 

That's well below the frost line here.

 

but since it is plowed, the frost drives deeper, so the extra protection is needed.

But I bet you knew that.

 

I generally shoot for at least 5’, especially on bare ground. We have one hydrant at 3.5’ that catches some winters.

The blueboard won’t keep the heat in the pex, but should help cut the temperature differential a bunch. I’m thinking the idea above of a drain tile below the pex would be smart for where I hope to eventually run a line. Till then I’m mostly just lurking on this page, soaking up whatever experience I can.

 

For the point of it being tougher to work with, you only put it in once. The previous owners of my place cheaped out when they put in our line, first 2-3 snowfalls you can tell where the line goes, as there's no snow the whole length 4' wide, every time I see it I'd like to kick the guy that made that decision where it hurts. IMO if your going to cheap out, just leave your windows open all winter long as well.

 

Now ask me how I really feel

 

I've done a few installs of OWB's with my dad over the years. Don't skimp on the insulated PEX, get the stuff in picture two.

Yes, it's a pita, but you only do it once.

 

Thanks for all the advice. I am going to purchase the closed cell. I have two runs to go in. 100' from owb to house and then another 50' to the shop. These lines will be buried at minimum if 40". Frost line for my area is 36".

Ill be feeding the power to the boiler from the panel in my shop. I spoke with the hvac guy that is going to be assisting me install. He is fairly confident he will be able to get a better price on the pex.

 

I had 85 feet of thermopex connecting my OPB (pellet boiler) to my house in Maine.
We only buried it about a foot deep and just laid the wire in the trench.
The ground over my pipe stayed frozen and the snow never melted.
Best investment in heating possible