I recently had a Bosch 3-ton Open Loop (Pump and Dump) 2-stage Geothermal Heat Pump installed. My HVAC installer did not initially set up the water lines correctly (see attached photo). He did not put any valves at all on the discharge line, even though a Taco Zone Control valve came with the unit. Obviously I then had a problem with water hammer. I contacted my well driller who has extensive experience in geo water line configuration and together we (believe) configured the lines correctly (see attached photo). The original configuration had a Honeywell DS06-101-LF pressure regulating valve and an adjustable flow regulator on the inlet line. Within a few days the unit froze up and my HVAC guy thought the flow control valve was malfunctioning and replaced it with a manual ball valve. Still had the same problem. When my well driller and I got together we removed the Honeywell valve and found that it was clogged up with sand. We then proceeded to re-configure the lines. Inlet: spin down filter > ball control valve Discharge: Taco slow opening zone control valve > flow regulator. (The Honeywell valve was removed.) We then experienced water hammer on the inlet line and installed a bladder tank as you can see in the photo. This helped but still experience a softer hammer. The Taco valve seems to be working properly, but there is now an issue with the discharge line being very noisy with the gurgling sound of water rushing though (but no more loud hammer). The 1" discharge line goes up then across the basement ceiling and connects with an elbow at a sidewall to a 1-1/4" line that drops down 6 feet and goes out underground to my pond. (Could the difference in line sizes cause the problem?) I think the issue with the inlet line still slightly hammering can be solved with tweeking the bladder tank. The more pressing issue is to try and solve the discharge line noise. Of note the unit requires 6 gpm minimum, but we have the all the valves wide open because this seems to give the best heat/fan performance (probably running 15 gpm). When we throttle back the gpm flow that seems to increase the discharge line flow noise. Both water line's entrance/exit points are located directly under my bedroom....so my sleep gets interrupted.