I plan to embark on a bit of DIY this summer by putting in a GSHP.  I would like to put in a horizontal field using 1 1/2" or 2" mains with several 3/4" slinky loops in parallel.  I am finding that the equipment needed to weld HDPE pipe is a minimum of $350 to purchase, and I would be using it for only this one project.  So, my question is, does anyone on these boards have a unit they are willing to sell or rent to me for the duration of my project (start 3-4 weeks from now, need welder for about a week)?

Please let me know if you have an unused unit you'd like to recoup some investment on by buying or renting it to me.

Thanks,
J

There was a geo installer who evidently always used PEX (ie, no fusing). The slightly thicker wall required a little more pipe, but I suspect that if there were problems with PEX in the ground, snow melting setups (and water service lines) wouldn't be using it.

Geothermal Supply Company will rent you the tools

good luck

Posted By jonr on 20 May 2011 06:02 PM
There was a geo installer who evidently always used PEX (ie, no fusing). The slightly thicker wall required a little more pipe, but I suspect that if there were problems with PEX in the ground, snow melting setups wouldn't be using it.

I am not sure if if the snowmelt pex and it's fittings is pressurized to 45-60 psi, and withstands a flow of a reynolds number of above 2500 for 50+ years. My bet would be on the HDPE.

Geo.....it's great they rent that stuff but man it is expensive! $100/day!!

Posted By robinnc on 21 May 2011 10:25 PM
Geo.....it's great they rent that stuff but man it is expensive! $100/day!!

I forgot to add that you might to ck craigslist. You never know.

Where are you buying your pipe? I would ask them for leads on rental/loaner fusion equipment. Also call some local installers. I have done fusion only for a fair amount of diy people, as well as purging. I like meeting new people and it matters not who did what as long as i get paid for my time.
Eric

You think you are going to fuse 2" HDPE with a $350 tool? Holy blistered hands Batman.
Start over with your design, then look at "geostab" fittings from Continental Industries.
J

While IGSHPA approves PEX, Geostab sounds better.

Over in the ecorenovator forum, there is a blog about DIY Geothermal. AC_Hacker made a fusion jig that meets his needs from an old waffle Iron. It might not be suitable for a professional with a very big job to do, but if it passes pressure testing,it must be OK. And cheap!

I had never heard of that forum before. Kinda kool what that guy put together.


http://ecorenovator.org/diy-ground-source-heat-pump-part-5-welding-plastic/

While interesting, I don't know of any sane person that would want to buy a house where a DIYer has jury-rigged major household systems. On the plus side of this setup, there may have been a nice residual sandwich smell before the unit first came in contact with the HDPE.

Jeks, If you are in the NY/NJ area, I would be happy to lend you mine. Have you considered manifolding inside the building? 95% of our horizontal fields do not contain any buried connections.

Thank you folks. I thank you for the help. I will definitely check out Geostab.

If I end up buying the tools instead of renting them, I'll possibly throw them on here afterwards for sale. Recoup some of my costs and others can then do the same. Buy, use, pass along. - John

John,
You need to think twice about design. Again fusing 2" is no picnic. Nor is that tool set $350.

Maybe someday some company will use the superior strength of PEX to create and approve a thin wall, high performance geo thermal loop tubing. Or someone will get approval for using flame treatment + flexible epoxy with HDPE.

Thank you all for the advice, I very much appreciate it. I've decided to purchase a welding kit. I will only use only 1-1/4 and 3/4 based on the socket dies included. I will be implementing a 'slinky' loop design in a 3 foot wide trench. So that the further trenches do not have too high a pressure drop, I am thinking I'll run 1-1/4 out to each loop, 3/4 to the loop and I'll return again with 1-1/4.

Does anyone have advice on loop design for a single long trench (based on my preferred trench location) vs. several shorter ones?

JEKS, another possible option is for you to do the pipe work, and hire a local pro to do the heat fusion. This way, you will have someone experienced and someone with the right tools to do the fusion.

JEKS,

your header needs to a step down step up reverse return header. Otherwise you will never purge all of the air from the system

you can read all about that here

Take a look at the software "Ground Loop Design" or "GeoAnalyst" if you want to explore different loop layouts.