DIY Digging trenches for Geothermal

[Tompet]

I bought my BH92 for that very reason. I dug 5 trenches 70'x3' wide for slinkies. 18" bucket. Do not remove soil first, it will make it worse. Did not take too long. Doing the geo install myself instead of "farming it out" paid for the tractor and backhoe.
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I had the predecessor of the op's 1710 (gc2310) and your bh92 is different level machine that would be successful for the project.

Best idea as op and another poster said is dig a test trench/hole 6' deep. You will experience the difference of task from digging a 2 or 3 feet deep trench with your machine.

Reread Digginit's post...take that advice in consideration too. Post what you think after test hole. If you're still confident...I guess go for it! If not, rent an excavator.

On last thing, can you dig and add coil(s) with these systems piece meal as you go along or does whole 600' need opened up with pipe installed at one time? Might be safer that way with extended time to open 600' of trench.

 

[millsan1]

I have a geo system. Are you sure 300' is going to be enough? Seems kind of light to me. Everything I have read and seen is more int he thousands of feet.

 

[Gofast]

Another option is to dig four 300’ 10” trenches. The advantage to that is you never have to get in the trench.
The pipe goes out 300’ you put two foot dirt back in the trench then the return pipe goes in the trench. Then you fill the trench back in.
Better system performance. My neighbor has a Mini excavator he would probably rent me. I would then use my tractor to fill the trenches back in.
I will do a test dig and decide.

We have Mini splits for heating and air right now. The digging can be spread over some time.

 

[buckeyefarmer]

Looks great how many ton unit did you put in? what MFG did you go with on the Geo unit?
How deep did you dig?

Comfort Aire units by heatcontrollers., same as climatemaster unit, same control boards.

I put in a 3ton and a 2 ton. One 70' trench per ton. Mine are 5' - 6' deep. Did one at a time, in parallel. Digging the next trench, piled top soil between trenches, then filled the other trench as i went.

 

[Gofast]

Is your system pressured how long have you had the system do you like it?

 

[ovrszd]

A trench 300' x 6' x 16" contains 2,400 cubic feet of dirt. That equals 89 cubic yards of dirt. An average tem wheeler dump truck will hold 11 cubic yards. That equals 8 dump truck loads.

So,,, do the math on your bucket and you can determine how many buckets it will take you. Estimate how long it takes to fill, swing, dump, return to the trench and you can get a ballpark idea. Add at least 10% because you will under estimate the time.

I think this will be multiple days. Many, many, many hours.

P.S. comparing a shallow trench is very deceiving.

 

[Gofast]

I like how you think.
If I used my 10” bucket 300’ * 6’ * 10” = 1500 cubic feet of dirt. 4 trenches 6,000 cubic feet of dirt.
222 cubic yards of dirt 20 dump trucks of dirt.

To be continued I need to see how much dirt the bucket holds.

I wounder if buying a Trencher Bucket would speed things up the pipe it only 3/4 inch.

 

[buckeyefarmer]

Another option is to dig four 300’ 10” trenches. The advantage to that is you never have to get in the trench.
The pipe goes out 300’ you put two foot dirt back in the trench then the return pipe goes in the trench. Then you fill the trench back in.
Better system performance. My neighbor has a Mini excavator he would probably rent me. I would then use my tractor to fill the trenches back in.
I will do a test dig and decide.

We have Mini splits for heating and air right now. The digging can be spread over some time.

300' straight pipe is way too little.

 

[ovrszd]

I like how you think.
If I used my 10” bucket 300’ * 6’ * 10” = 1500 cubic feet of dirt. 4 trenches 6,000 cubic feet of dirt.
222 cubic yards of dirt 20 dump trucks of dirt.

To be continued I need to see how much dirt the bucket holds.

I wounder if buying a Trencher Bucket would speed things up the pipe it only 3/4 inch.

Soil types vary soooo much. Here a 12" bucket is worthless unless we are in serious drought. Normal soil moisture conditions and it will be 75% packed with dirt after half a dozen dips. Then productivity really sails..... Away......

 

[Gofast]

I did a test dig and this is not going to happen with my 1710.
I can use it to dig close to the house and to the fence that is about 25’.

It will do great to fill the trench back in and level it out but there is no way it is going to do the whole dig.

It is 600’ per ton but I am going to put in 4 600’ loops. That is 600 foot more loop than is required.

Now I will either have to talk to my neighbor about renting his mini excavator.
or maybe have a track hoe with a 3’ bucket dig the two trenches instead of 4.
I will cover it all back up with my 1710.