My 28-year-old bard unit compressor is locked up. I know it’s time to do a geothermal change out. In my research I am leaning towards water furnace. Deciding if I should go with a 4 ton series 7 or a series 5. I have a 1-1/4” horizontal ground loop 2000’ long buried 6’ deep. My supply duct is 12 x 20 running through the crawlspace. Of course it gets smaller as it goes. My home is a 2550 square-foot ranch style home(single level). It is a well insulated home built in 1992. The bard geothermal unit was original to the house. I would love to hear your advice. Which water furnace unit do I go with? Or is there another brand you would recommend.