I have recently gained a customer with an existing TETCO AC50 Geothermal open loop with a C36 Cooling Coil. She recently had to have her well re-drilled and the aquifer the well company tapped into has an insane amount of iron in the water. The company that serviced her equipment before me, installed a spun cotton water filter to help with the iron problem. She is having to change this every 2 weeks to keep the unit running. It has also been very unreliable in the winter for her as well. She recently decided she wants to go with a closed loop system and eliminate the open loop setup all together. The IOM manual on this unit only show an open loop type setup. Has anybody had any luck converting this unit to a closed loop? It seems the same water flow and Delta T would apply with the closed loop if properly sized. Any ideas or suggestions? Thanks!