Hi, I have a Grundfos recirculating pump that I installed this weekend. I installed brass unions on each side in the event that I have to remove the assembly for repair in the future. Everything works fine, but one of the two brass unions (brand new) that I installed is leaking. I tried tightening it down further, but with no luck. I noticed that the angle of one of the pipes approaching is at a slightly different angle that the pump side. How much tolerance is there for keeping the two sides (flare to other side) perfectly straight? I'm assuming that the connection has to fit exactly for the fit to work properly.
Was the proper installation method to assemble the two unions to the pump, tighten the unions and then solder the sweat ends of the union into my piping system? I soldered the sweat ends first with the unions 'loose' and then tightened them down.