Having a 5T, two speed, closed loop (vertical), DSH WF-Envision being installed(loop wells are in). Installer has grouted the wells (3x at 250', 5" bore, 16' spacing, reverse return) with 100% Bentonite vs. mix. Issue is per manufacturer specs (found after the grouting was done) that they suggest at least a 4:1 silica sand mix to bring the 100% Bentonite Grout from 0.4 BTU-ft/F* to 1.0 or so.

Earth in bore is nearly continuous limestone (Average rock... 1.4 BTU-ft/F*).

So I have a situation where my first energy transfer is wounded by the installation, and this seems a big deal...

I don't have a functional Ground Loop Design or similar software, but from the demo, this is NOT a good solution.. (dry sandy soil is ~ 0.4 BTU-ft/F*)...

Can anyone let me know if I'm wounded or this is not a factor.. I'd like to know prior to confronting the contractor..


Evaluation Details:
Ground Temp ~ 57*F (nearly solid limestone in cuttings)
Heat Load: 49KBTU/HR
Cooling Load: 80KBTU/HR
Loop piping 1", bore 5", depth 250ft, 3 wells, spaced 16ft, reverse return, closed loop
Flow pump: FC-2, should provide 18gpm (including both loop and unit)
Heat Pump: WF Envision 5T, ECM, DSH, 15kW strip