DIY Digging trenches for Geothermal

[edgarrian]

I dug the trenches for my gramps geo thermal and the guys where there to do it as i dug. As i have already mentioned with your trench depth being 6 foot deep you will need to fold the sides back especially if the trench is taking in water. Make **** sure you don't let the trench cave in on one of those guys.

 

[ovrszd]

Huge difference between a 4' trench and a 6' trench!!!

 

[edgarrian]

I have heard of guys getting killed in a 4 ft trench. Guy is by himself, digs the trench. Gets out to lay his pipe. Bends over and trench caves in. It really doesn't take much. 6 ft trench is generally going to be over a guys a head. As i said a few times in this thread you need to be mindful of the trench taking in water. If trench starts falling in then you need to bail that section even more. What type of soil do you have. Is it sandy, sandy with clay, or clay.

Huge difference between a 4' trench and a 6' trench!!!

 

[Hickorypond]

I dug 6' for the lines to my pond with my 1720. Most installers put a manifold in the ground this is where you will have leaks and can have a cave in, don't get in the trench. Run complete loops inside near your pump and valve them. it's way easier to fix if you have a leak later. I put 2 spare loops in just in case. Check out B&D flow centers for self purging pumps.I put a 2 stage unit in and don't have backup heat, I'm good to 0 degrees and cooling is sized right. Do a manual J for your demand load,you can find an online calculator. I have about $6000 in mine for everything. On another note I baled some late hay with my 1720 this week using a small round baler.

 

[Gofast]

We have red clay here it is not real wet. The clay is very hard and it makes nice stable sides in the trench.
I will run all loops under or through the footers and the manifold will be in the crawl space.
I did not know 1720 had enough power to run a round hay bailer what king of bailer was it?

 

[LD1]

I was wondering if others did this. If a loop did not hold pressure and you had it covered up it would be a huge deal.
I don’t have great luck I think I will do this as well.

We have red clay here it is not real wet. The clay is very hard and it makes nice stable sides in the trench.
I will run all loops under or through the footers and the manifold will be in the crawl space.
I did not know 1720 had enough power to run a round hay bailer what king of bailer was it?

Pressure testing prior to backfill is great....BUT....the greatest risk of developing a leak is from damage during backfill. Dropping a 20# rock with a sharp edge down on the pipe that you didnt see in the spoil pile.

So testing AFTER is also a must.

I have ZERO connections or welds in the ground. For my 600' loops (I actually used 800') continuous lengths of pipe, all stubbed into the house to a manifold. ALL connections are in the house....thus greatly reducing the odds of ever developing a leak outside and having to dig it up again.

 

[Diggin It]

Mine says it will dig 77 inches or so, but I doubt I'd ever try to dig trenches that deep, that wide and that long. Geo might be nice, but I also doubt I'd ever see the return on investment since I'm sure it's rather expensive.

Thinking another couple of seconds tells me I don't even have room to do it given the layout and terrain of my property and the presence of the utility water line in my front yard.

 

[Hickorypond]

I imported a Runshine 850 mini baler from Alibaba and a rotary rake also.There are a couple of US sites selling them for $7000, I paid $1800 plus import fees. I bought my property to keep busy, it would never pencil out. I would borrow a backhoe for your ground loops.Clay is good ,dry is going to need more loop length. I used 800' loops also. Like LD1 said the problem is watching out for rocks when backfilling.

 

[LD1]

Mine says it will dig 77 inches or so, but I doubt I'd ever try to dig trenches that deep, that wide and that long. Geo might be nice, but I also doubt I'd ever see the return on investment since I'm sure it's rather expensive.

Thinking another couple of seconds tells me I don't even have room to do it given the layout and terrain of my property and the presence of the utility water line in my front yard.

Geo isnt for everyone. But if you are capable of doing some of the work yourself....ROI is no different (or even better) than a conventional Air to air system.

So if you are building a new house and comparing air-to-air vs geo......the numbers make more sense.

If you have a perfectly working conventional HVAC system.....it dont make much sense to spend thousands of dollars to switch to geo for only a few hundred a year savings.

Now if your conventional system fails, and you are staring at a $5k or a $10k replacement of the system or components....its time to re-evaluate.

And for not having the land....not a deal breaker. They can do "vertical" loops. So instead of a 300' trench to do an out-and-back run of 600' of pipe....they just drill a well 300' down into the ground. Expensive....yes. But so is digging the trenches if you arent capable of doing it yourself either. But it does give the option of GEO to people who's lot size is measured in Sqft rather than acres

 

[Gofast]

Geothermal fed tax credit is 30% and our state SC is 25% that is 55% off the cost so at least this year it can compete with a heat pump install.
About 5 years ago I did a DIY solar install 12.5 KW covers our home and driving our Chevy Volt 19K electric miles a year.
In the last 5 years we have driven 90K electric miles on solar power.

@Hickorypond that hay baler is very cool.
I am going to put in 2400 pipe for a 3 ton system that works out to 800' a ton.