Why is it recommended to install some residential water meters horizontally.
For Multi-jet dry type meter: The measuring impeller and register are magnetically coupled not directly connected, it is designed to be installed horizontally to insure the actual meter accuracy stays within the published accuracy curves. If the meter is installed vertically the distance between the two magnets will change therefore the connecting force of the two magnets will change and can possibly even intermittently lose total connection at higher velocities therefore causing a decrease in accuracy.
Meters that should be installed Horizontally: WM-PC, WM-NLC, WM2, WM2-H
Meters that can be installed Horizontally or Vertically: WM, WM-FAM, WM-H, T-10