Should there be some type of fitting on the bottom of the drop pipe in a discharge well to create a small amount of back pressure? Or something else? Thanks!
Yes. A foot valve to keep a column of water in the interior plumbing and to prevent possible syphoning.
All of the foot valves I see are for wells, so they are one way in order to allow water to be pumped out of the well. Is there a type for geothermal where the water goes out of the foot valve?
O.K. I need to step back. Are you discharging below a waterline? If so, you just need an interior valve on the discharge side of the heat pump (taco, belimo). When discharging into a sump or site drainage, we use a pressure release foot valve to hold a column of water in the discharge piping to prevent air/growth.
