I did the maintenance on the equipment here. I replaced the air filters with ones provided by the customer for #3 and #4. I checked the electrical wiring and electrical systems, all are within specification except for the voltage absorption system for #4, which was subsequently replaced. I calculated heat of extraction for all geos and thoroughly checked #1 and #2 because the customer had concerns about multiple times the units stop heating with no fault codes displayed. After several phone calls with WF it was decided that the only cause of this is that the control board stops sending voltage to the compressor contactor. I filled out a parts order form and the customer paid $250 & $250 as a deposit. The boards will be ordered from WF. I pressurized the ground loops. Temperature rise for #3 and #4 is very good but auxiliary heat also works. Units are operating normal.